Lessons learned from WebAPI and MVC Implementations

My Notes on a painful journey to learn, make and publish a Azure hosted MVC, Sinlge-Page application, Android client app and a WebAPI working with-one another. Software technology can be real pain in the ass!!!

JSON and Self referencing loop

If you get the following error:

Self referencing loop detected for property ‘your model’ with type ‘System.Data.Entity.DynamicProxies


Loop Reference handling in Web API

My Solution:

I used [JsonIgnore] attribute to tell the proper inheritance to JSON serialization.

using Newtonsoft.Json;

public partial class Set
public Set()
this.Exercises = new HashSet<Exercise>();

public long Id { get; set; }
public string Name { get; set; }
public string UserId { get; set; }

public virtual ICollection<Exercise> Exercises { get; set; }

public partial class ExerciseRecord
public long Id { get; set; }
public double Record { get; set; }
public System.DateTime Date { get; set; }
public System.DateTime StartDate { get; set; }
public System.DateTime EndDate { get; set; }
public long ExerciseId { get; set; }

public virtual Exercise Exercise { get; set; }

public partial class Exercise
public Exercise()
this.ExerciseAttributes = new HashSet<ExerciseAttribute>();
this.ExerciseRecords = new HashSet<ExerciseRecord>();

public long Id { get; set; }
public string Name { get; set; }
public double Target { get; set; }
public long SetId { get; set; }
public virtual Set Set { get; set; }
public virtual ICollection<ExerciseAttribute> ExerciseAttributes { get; set; }
public virtual ICollection<ExerciseRecord> ExerciseRecords { get; set; }


MVC loads older script files

This is due to browser script caching. The easiest solution for this is to set the browser which you are using to debug to retrieve the newest versions of web page content on each time you visit a webpage.

Missing Key definition from Model when creating a controller

You might get an error like this: EntityType ‘your type’ has no key defined. Define the key for this EntityType.

To fix such problems simply add this namespace definitions:

using System.ComponentModel.DataAnnotations;

And then define in your data model a key like this:

public class ColumnDataHighChart
public int ID { get; set; }
public String Title { get; set; }
public String SubTitle { get; set; }
public IList<String> xAxisCategories { get; set; }
public String yAxisTitle { get; set; }
public IList<SeriesDataHighChart> Series { get; set; }



Intercepting web requests


I have two ways of doing this:

  1. A delegation handler
  2. Or an action filter for a controller.

Delegation handler

DelegatingHandler Class

Sample code:

public class AuthHandler : DelegatingHandler
protected async override Task<HttpResponseMessage> SendAsync(
HttpRequestMessage request, CancellationToken cancellationToken)
// Call the inner handler.
var response = await base.SendAsync(request, cancellationToken);
return response;

Action filter for a controlle

Notice that for MVC and Web API there are two different sets of action filter definitions:



MVC Sample:

public class AuthenticationActionFilterHelper : ActionFilterAttribute
public override void OnActionExecuting(ActionExecutingContext filterContext)
if (HttpContext.Current != null && HttpContext.Current.User != null && HttpContext.Current.User.Identity.IsAuthenticated)
if (SessionHelper.LoggedInUser<AspNetUser>(HttpContext.Current.User.Identity.Name) == null)
//SessionHelper.UserSessionID = user.Id;
AspNetUsersController aspUserCon = new AspNetUsersController();
var sessionUser = aspUserCon.GetUser(HttpContext.Current.User.Identity.Name);
//SessionHelper.UserSessionID = user.UserName;
SessionHelper.LoggedInUser<AspNetUser>(sessionUser, sessionUser.UserName);


WebAPI Sample:

public class AuthenticationActionFilterHelper : ActionFilterAttribute
public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)

public override System.Threading.Tasks.Task OnActionExecutedAsync(HttpActionExecutedContext actionExecutedContext, System.Threading.CancellationToken cancellationToken)
return base.OnActionExecutedAsync(actionExecutedContext, cancellationToken);

public override void OnActionExecuting(HttpActionContext actionContext)
if (HttpContext.Current != null && HttpContext.Current.User != null && HttpContext.Current.User.Identity.IsAuthenticated)
if (SessionHelper.LoggedInUser<AspNetUser>(HttpContext.Current.User.Identity.Name) == null)
//SessionHelper.UserSessionID = user.Id;
AspNetUsersController aspUserCon = new AspNetUsersController();
var sessionUser = aspUserCon.GetUser(HttpContext.Current.User.Identity.Name);
//SessionHelper.UserSessionID = user.UserName;
SessionHelper.LoggedInUser<AspNetUser>(sessionUser, sessionUser.UserName);

public override System.Threading.Tasks.Task OnActionExecutingAsync(HttpActionContext actionContext, System.Threading.CancellationToken cancellationToken)
return base.OnActionExecutingAsync(actionContext, cancellationToken);


Lambda Expression “Magic” 🙂

Retrieve distinct parent from child elements

As the title suggests I needed to retrieve the parent from a multilevel data set:


First I needed to get the child elements and in this exmaple it is assumed that you have the child elements retrieved.

Once you have the child elements it is time to get the distinct parent elements. for this I needed a way to group the distinct parent from the child elements. Here are my steps:

  • Get child elements:

ExerciseRecordsController exerciseRecordsController = new ExerciseRecordsController();
var exerciseRecordsData = exerciseRecordsController.GetExerciseRecords().Where(er => er.Date > startDate && er.Date < endDate && er.Exercise.Set.UserId.ToLower().CompareTo(this.user.Id.ToLower()) == 0);

  • Define a custom extension named “DistinctBy”

public static class LambdaExtensions
public static IEnumerable<t> DistinctBy<t>(this IEnumerable<t> list, Func<t, object> propertySelector)
return list.GroupBy(propertySelector).Select(x => x.First());
} Original code from: http://www.elevenwinds.com/linq-distinctby-with-lambda-expression-parameter

  • Apply the new extension on the data set

var setsData = exerciseRecordsData.DistinctBy(o => o.Exercise.SetId).Select( o => o.Exercise.Set);

How to create/populate a collection with data with an unknown data type

You may ask yourself why would anyone needs this? Well I do not why would others needs this but I came into a situation where I needed this.

I had a solution where I needed to be able to create data from a back-end server WebAPI to a JS HighCharts JS library without knowing what kind of data I would be processing, also I wanted to have the possibility to extend the back-end code so that it can return any kind of data to the client and let the client figure out what to do with the data.

So how to do this?

In a human language it goes something like this: Use LINQ in your code to go through the data set, select your data and return it as and array of objects, then create a new collection by passing to the constructor your processed data as an array of objects. Ofcourse your collection must store objects as well. The data type information is going to be stored because every class in C# is a descendant of the Object class.

public class SeriesDataHighChart
public long ID { get; set; }
public String Name { get; set; }
public IList<object> Data { get; set; }


// One series corresponds to one set and data for each month
SeriesDataHighChart seriesData = new SeriesDataHighChart();

seriesData.ID = chartSet.Id;
seriesData.Name = chartSet.Name;
var seriesMonthsActivityCountData = (from monthActivityCount in chartSet.ChartSetMonthsData
select new object[] { monthActivityCount.ActivityCount as object });
seriesData.Data = new List<object>(seriesMonthsActivityCountData.ToArray());



You could also return an array of more complex object such as a key value pairs:

var sd = from d in unparsedData
select new object[] { d.Key as object, d.Value as object };

newSeries.Data = new Data(sd.ToArray());

Avoiding “Sequence contains no elements” exception in object initializers

If you have something like this in your code:

chartExercise.ChatMonthsData.Add(new ChartExerciseMonthData
ActivityCount = exercise.ExerciseRecords.Where(m => m.Date.Month == month && m.Date >= startDate && m.Date <= endDate).Count(),
StartDate = DateTime.Now.StartOfMonth(month),
EndDate = DateTime.Now.EndOfMonth(month),
MonthRecordAverage = exercise.ExerciseRecords.Where(m => m.Date.Month == month && m.Date >= startDate && m.Date <= endDate).Average(a => a.Record)



The Average lambda expression will throw the above exception error message because the Where clause may return Zero elements back(Notice that for example the Count expression will not throw a similar exception).

To fix(go around the problem, yes there might be other solutions but this was mine at the moment 🙂 ) I created an anonymous function that checks if there are elements returned by the clause and only then perform the Average operation on the elements. The solution is highlighted with the green color.

chartExercise.ChatMonthsData.Add(new ChartExerciseMonthData
ActivityCount = exercise.ExerciseRecords.Where(m => m.Date.Month == month && m.Date >= startDate && m.Date <= endDate).Count(),
StartDate = DateTime.Now.StartOfMonth(month),
EndDate = DateTime.Now.EndOfMonth(month),
MonthRecordAverage = new Func<double>(() => {
double averageRecord = 0;
var exerciseRecordByDateRange = exercise.ExerciseRecords.Where(m => m.Date.Month == month && m.Date >= startDate && m.Date <= endDate);
if (exerciseRecordByDateRange.Count() > 0)
averageRecord = exerciseRecordByDateRange.Average(a => a.Record);

return (averageRecord);

 Get the count for a complex data structure/hierarchy, tree like

A rather simple implementation, choose to retrieve any records inside your main records set with a where:

set.Exercises.Where(o => o.ExerciseRecords.Any(m => m.Date.Month == month)).Count()

Update Azure SQL Database via SQL Server management studio and Generated scripts

  1. Mouse second button on database > Taskas > Generate Scripts > Choose your objects (Chose objects view) > Select “Advanced” button, then in the “Script for the database engine type” select option Windows Azure SQL Database
  2. Next open the database connection with management studio to your Azure SQL Database.
  3. Create a new empty database
  4. Open a new query windows and simply add the generated script to this window and run the script against the new empty database. This will create the structure and data if you selected so.

After deploying your WebAPI you get a following error when accessing your database data “There is already an open DataReader associated with this Command which must be closed first.”

To fix this error simply add the following to your connection strings used in your web api in Azure MultipleActiveResultSets=true.

Enable WebAPI Cross-Origin Resource Sharing (CORS)

You might run into problems after deploying your WebAPI to Azure and trying to access your api from different origins. Here is a solution:


Summary of the article above: Install the following nuget package in your WebAPI project: Microsoft.AspNet.WebApi.Cors

In your webapiconfig add the following(in green):

public static class WebApiConfig
public static void Register(HttpConfiguration config)
// Web API configuration and services
// Configure Web API to use only bearer token authentication.
config.Filters.Add(new HostAuthenticationFilter(OAuthDefaults.AuthenticationType));

var cors = new EnableCorsAttribute(“*”, “*”, “*”);

// Web API routes

name: “DefaultApi”,
routeTemplate: “api/{controller}/{id}”,
defaults: new { id = RouteParameter.Optional }

config.MessageHandlers.Add(new Handler.AuthHandler());

Next add the following to your ApplicationOAuthProvider.GrantResourceOwnerCredentials function:

public override async Task GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context)
context.OwinContext.Response.Headers.Add(“Access-Control-Allow-Origin”, new[] { “*” });
var userManager = context.OwinContext.GetUserManager<ApplicationUserManager>();

ApplicationUser user = await userManager.FindAsync(context.UserName, context.Password);
//SessionHelper.UserSessionID = user.Id;
AspNetUsersController aspUserCon = new AspNetUsersController();
var sessionUser = aspUserCon.GetUser(user.Id);
//SessionHelper.UserSessionID = user.UserName;
SessionHelper.LoggedInUser<AspNetUser>(sessionUser, user.UserName);
if (user == null)
context.SetError(“invalid_grant”, “The user name or password is incorrect.”);

ClaimsIdentity oAuthIdentity = await user.GenerateUserIdentityAsync(userManager,
ClaimsIdentity cookiesIdentity = await user.GenerateUserIdentityAsync(userManager,

AuthenticationProperties properties = CreateProperties(user.UserName);
AuthenticationTicket ticket = new AuthenticationTicket(oAuthIdentity, properties);


Notice that these changes may have undesired effects. Find out if these are suitable to your needs.

Using Lamba expression to process SharePoint objects (or any data you need to process)

This is just a trick to make your life easier. You can use this against any data in SharePoint as long as you do not need performance critical functionality. Remember that doing lambda expressions against big objects such as get an SPWeb or going through a list of SPWeb is still going to cost you the memory allocation and CPU utilization.

Sample how to remove an event receiver from a list:

using System.Linq;

var eventReceiver = list.EventReceivers.Cast<SPEventReceiverDefinition>().SingleOrDefault(o => o.Class.ToLower().Contains(receiverClass.ToLower()));
if (eventReceiver != null)
var allowUnsafeUpdates = web.AllowUnsafeUpdates;
web.AllowUnsafeUpdates = true;

web.AllowUnsafeUpdates = allowUnsafeUpdates;

Remember the concepts Late binding, Delayed Execution and Captured Variables.

Check you this Explanation from StackOverflow http://stackoverflow.com/questions/8930024/linq-late-binding-confusion =>

Late-binding: This is where the meaning of code is determined after it was compiled. For example, x.DoStuff() is early-bound if the compiler checks that objects of x‘s type have a DoStuff() method (considering extension methods and default arguments too) and then produces the call to it in the code it outputs, or fails with a compiler error otherwise. It is late-bound if the search for the DoStuff() method is done at run-time and throws a run-time exception if there was no DoStuff() method. There are pros and cons to each, and C# is normally early-bound but has support for late-binding (most simply through dynamic but the more convoluted approaches involving reflection also count).

Delayed execution: Strictly speaking, all Linq methods immediately produce a result. However, that result is an object which stores a reference to an enumerable object (often the result of the previous Linq method) which it will process in an appropriate manner when it is itself enumerated. For example, we can write our own Take method as:

private static IEnumerable<T> TakeHelper<T>(IEnumerable<T> source, int number)
  foreach(T item in source)
    yield return item;
    if(--number == 0)
      yield break;
public static IEnumerable<T> Take<T>(this IEnumerable<T> source, int number)
  if(source == null)
    throw new ArgumentNullException();
  if(number < 0)
    throw new ArgumentOutOfRangeException();
  if(number == 0)
    return Enumerable.Empty<T>();
  return TakeHelper(source, number);

Now, when we use it:

var taken4 = someEnumerable.Take(4);//taken4 has a value, so we've already done
                                    //something. If it was going to throw
                                    //an argument exception it would have done so
                                    //by now.

var firstTaken = taken4.First();//only now does the object in taken4
                                        //do the further processing that iterates
                                        //through someEnumerable.

Captured variables: Normally when we make use of a variable, we make use of how its current state:

int i = 2;
string s = "abc";
i = 3;
s = "xyz";

It’s pretty intuitive that this prints 2 and abc and not 3 and xyz. In anonymous functions and lambda expressions though, when we make use of a variable we are “capturing” it as a variable, and so we will end up using the value it has when the delegate is invoked:

int i = 2;
string s = "abc";
Action λ = () =>
i = 3;
s = "xyz";

Creating the λ doesn’t use the values of i and s, but creates a set of instructions as to what to do with i and s when λ is invoked. Only when that happens are the values of i and s used.

Putting it all together: In none of your cases do you have any late-binding. That is irrelevant to your question.

In both you have delayed execution. Both the call to Take and the call to Where return enumerable objects which will act upon arr when they are enumerated.

In only one do you have a captured variable. The call to Take passes an integer directly to Take and Take makes use of that value. The call to Where passes a Func<int, bool> created from a lambda expression, and that lambda expression captures an int variable. Where knows nothing of this capture, but the Func does.

That’s the reason the two behave so differently in how they treat cutoff. ” http://stackoverflow.com/questions/8930024/linq-late-binding-confusion


Microsoft sources of info:

Lambda Expressions (C# Programming Guide)

Getting Started with LINQ in C#

101 LINQ Samples

Good to know!?: .NET – Accessing, Querying and Manipulating data with Entity Framework


I gathered some links and resources on data manipulation with the .NET Framework. Hope this helps and works as a reference card what is available:

ADO.NET http://msdn.microsoft.com/en-us/library/e80y5yhx(v=vs.110).aspx
Entity Framework http://msdn.microsoft.com/en-US/data/ef
Configuring Parameters and Parameter Data Types http://msdn.microsoft.com/en-us/library/yy6y35y8(v=vs.110).aspx
.NET Framework Data Providers http://msdn.microsoft.com/en-us/library/a6cd7c08(v=vs.110).aspx
DataSet Class http://msdn.microsoft.com/en-us/library/system.data.dataset.aspx
Retrieving Data Using a DataReader http://msdn.microsoft.com/en-us/library/haa3afyz(v=vs.110).aspx
Entity Framework – Database First http://msdn.microsoft.com/en-us/data/jj206878.aspx
Entity Framework- Code First to a New Database http://msdn.microsoft.com/en-us/data/jj193542.aspx
ADO.NET Entity Data Model Designer http://msdn.microsoft.com/en-us/library/vstudio/cc716685(v=vs.100).aspx
Entity Data Model Wizard http://msdn.microsoft.com/en-us/library/vstudio/bb399247(v=vs.100).aspx
Create Database Wizard (Master Data Services Configuration Manager) http://technet.microsoft.com/en-us/library/ee633799.aspx
Update Model Wizard (Entity Data Model Tools) http://msdn.microsoft.com/en-us/library/vstudio/cc716705(v=vs.100).aspx
Using the DbContext API http://msdn.microsoft.com/en-us/data/gg192989.aspx
Table-per-Type vs Table-per-Hierarchy Inheritance http://blog.devart.com/table-per-type-vs-table-per-hierarchy-inheritance.html
Relational database management system http://en.wikipedia.org/wiki/Relational_database_management_system
ObjectContext Class http://msdn.microsoft.com/en-us/library/system.data.objects.objectcontext(v=vs.110).aspx
DBContext vs ObjectContexts http://www.entityframeworktutorial.net/EntityFramework4.3/dbcontext-vs-objectcontext.aspx
DbContext Class http://msdn.microsoft.com/en-us/library/system.data.entity.dbcontext(v=vs.113).aspx
ObjectContext management http://msdn.microsoft.com/en-us/library/system.data.objects.objectcontext.contextoptions(v=vs.110).aspx
How to: Use Lazy Loading to Load Related Objects http://msdn.microsoft.com/en-us/library/vstudio/dd456846(v=vs.100).aspx
EntityObject Class http://msdn.microsoft.com/en-us/library/system.data.objects.dataclasses.entityobject(v=vs.110).aspx
EdmEntityTypeAttribute Class http://msdn.microsoft.com/en-us/library/system.data.objects.dataclasses.edmentitytypeattribute(v=vs.110).aspx
SerializableAttribute Class http://msdn.microsoft.com/en-us/library/system.serializableattribute.aspx
DataContractAttribute Class http://msdn.microsoft.com/en-us/library/system.runtime.serialization.datacontractattribute.aspx
Entity Framework (EF) Documentation http://msdn.microsoft.com/en-us/data/ee712907.aspx
OData protocol http://www.odata.org/
Open Data Protocol by Example http://msdn.microsoft.com/en-us/library/ff478141.aspx
WCF Data Services Overview http://msdn.microsoft.com/en-us/library/cc668794(v=vs.110).aspx
Using the REST Interface http://msdn.microsoft.com/en-us/library/ff798339.aspx
Understanding Service-Oriented Architecture http://msdn.microsoft.com/en-us/library/aa480021.aspx
WCF Data Services 4.5 http://msdn.microsoft.com/en-us/library/cc668792(v=vs.110).aspx
Advanced using OData in .NET: WCF Data Services http://www.codeproject.com/Articles/135490/Advanced-using-OData-in-NET-WCF-Data-Services
ObjectCache Class http://msdn.microsoft.com/en-us/library/vstudio/system.runtime.caching.objectcache
HttpContext.Cache Property http://msdn.microsoft.com/en-us/library/system.web.httpcontext.cache(v=vs.110).aspx
ASP.NET Application State Overview http://msdn.microsoft.com/en-us/library/ms178594.aspx
ASP.NET Session State Overview http://msdn.microsoft.com/en-us/library/ms178581.aspx
Understanding ASP.NET View State http://msdn.microsoft.com/en-us/library/ms972976.aspx
CacheItemPolicy Class http://msdn.microsoft.com/en-us/library/system.runtime.caching.cacheitempolicy(v=vs.110).aspx
CacheItemPriority Enumeration http://msdn.microsoft.com/en-us/library/system.web.caching.cacheitempriority.aspx
ChangeMonitor Class http://msdn.microsoft.com/en-us/library/system.runtime.caching.changemonitor(v=vs.110).aspx
CacheDependency Class http://msdn.microsoft.com/en-us/library/system.web.caching.cachedependency.aspx
System.Transactions Namespace http://msdn.microsoft.com/en-us/library/system.transactions.aspx
EntityTransaction Class http://msdn.microsoft.com/en-us/library/system.data.entityclient.entitytransaction.aspx
EntityCommand Class http://msdn.microsoft.com/en-us/library/system.data.entityclient.entitycommand.aspx
EntityConnection Class http://msdn.microsoft.com/en-us/library/system.data.entityclient.entityconnection(v=vs.110).aspx
SqlTransaction Class http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqltransaction.aspx
System.Data.EntityClient Namespace http://msdn.microsoft.com/en-us/library/system.data.entityclient(v=vs.110).aspx
IsolationLevel Enumeration http://msdn.microsoft.com/en-us/library/system.data.isolationlevel.aspx
TransactionScope Class http://msdn.microsoft.com/en-us/library/system.transactions.transactionscope.aspx
System.Xml Namespaces http://msdn.microsoft.com/en-us/library/gg145036(v=vs.110).aspx
XmlWriter Class http://msdn.microsoft.com/en-us/library/system.xml.xmlwriter.aspx
XML Documents and Data http://msdn.microsoft.com/en-us/library/2bcctyt8(v=vs.110).aspx
XmlDocument Class http://msdn.microsoft.com/en-us/library/system.xml.xmldocument.aspx
XmlReader Class http://msdn.microsoft.com/en-us/library/vstudio/system.xml.xmlreader
XPath Examples http://msdn.microsoft.com/en-us/library/ms256086(v=vs.110).aspx
LINQ to XML [from BPUEDev11] http://msdn.microsoft.com/en-us/library/bb387098.aspx
LINQ to XML Overview http://msdn.microsoft.com/en-us/library/bb387061.aspx
XElement Class http://msdn.microsoft.com/en-us/library/system.xml.linq.xelement.aspx
LINQ (Language-Integrated Query) http://msdn.microsoft.com/en-us/library/bb397926.aspx
DbContext.SaveChanges Method http://msdn.microsoft.com/en-us/library/system.data.entity.dbcontext.savechanges(v=vs.113).aspx
DbContext.Set<TEntity> Method http://msdn.microsoft.com/en-us/library/gg696521(v=vs.113).aspx
Object-relational impedance mismatch http://en.wikipedia.org/wiki/Object-Relational_impedance_mismatch
Loading Related Entities (Eager Loading,  Lazy Loading, Explicitly Loading) http://msdn.microsoft.com/en-us/data/jj574232.aspx
Demystifying Entity Framework Strategies: Loading Related Data (Eager Loading,  Lazy Loading, Explicitly Loading) http://msdn.microsoft.com/en-us/magazine/hh205756.aspx
Precompiling LINQ Queries http://msdn.microsoft.com/en-us/magazine/ee336024.aspx
Entity Framework 5: Controlling automatic query compilation http://blogs.msdn.com/b/stuartleeks/archive/2012/06/12/entity-framework-5-controlling-automatic-query-compilation.aspx
Improve Performance with Entity Framework 5 http://devproconnections.com/entity-framework/improve-performance-entity-framework-5
Queries in LINQ to Entities http://msdn.microsoft.com/en-us/library/vstudio/bb399367(v=vs.100).aspx
LINQ to Entities: Basic Concepts and Features http://www.codeproject.com/Articles/246861/LINQ-to-Entities-Basic-Concepts-and-Features
LINQ to Objects http://msdn.microsoft.com/en-us/library/bb397919.aspx
SqlConnectionStringBuilder Class http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlconnectionstringbuilder.aspx
ObjectQuery<T> Class http://msdn.microsoft.com/en-us/library/bb345303(v=vs.110).aspx
ObjectQuery Class http://msdn.microsoft.com/en-us/library/system.data.objects.objectquery(v=vs.110).aspx
ObjectQuery.ToTraceString Method http://msdn.microsoft.com/en-us/library/system.data.objects.objectquery.totracestring(v=vs.110).aspx
System.Data.SqlClient Namespace http://msdn.microsoft.com/en-us/library/System.Data.SqlClient(v=vs.110).aspx
SqlConnection Class http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlconnection.aspx
SQL Server Connection Pooling (ADO.NET) http://msdn.microsoft.com/en-us/library/vstudio/8xx3tyca%28v%3Dvs.100%29
DataTable Class http://msdn.microsoft.com/en-us/library/system.data.datatable.aspx
DataSet Class http://msdn.microsoft.com/en-us/library/system.data.dataset.aspx
DataAdapter Class http://msdn.microsoft.com/en-us/library/system.data.common.dataadapter.aspx
SqlCommand Class http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.aspx
SqlCommand.CommandText Property http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.commandtext(v=vs.110).aspx
CommandType Enumeration http://msdn.microsoft.com/en-us/library/system.data.commandtype(v=vs.110).aspx
SqlDataAdapter Class http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqldataadapter.aspx
SqlCommand.ExecuteScalar Method http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.executescalar(v=vs.110).aspx
SqlCommand.ExecuteReader Method http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.executereader(v=vs.110).aspx
SqlDataReader Class http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqldatareader.aspx
SqlDataReader.Read Method http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqldatareader.read.aspx
DbDataAdapter.Fill Method (DataSet) http://msdn.microsoft.com/en-us/library/zxkb3c3d(v=vs.110).aspx
DbDataAdapter.Update Method (DataSet) http://msdn.microsoft.com/en-us/library/at8a576f(v=vs.110).aspx
DataAdapter.AcceptChangesDuringFill Property http://msdn.microsoft.com/en-us/library/system.data.common.dataadapter.acceptchangesduringfill(v=vs.110).aspx
Working with Datasets in Visual Studio http://msdn.microsoft.com/en-us/library/8bw9ksd6%28v%3Dvs.110%29.aspx
SqlParameter Class http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlparameter.aspx
EF Designer TPT Inheritance http://msdn.microsoft.com/en-us/data/jj618293.aspx
Walkthrough: Mapping Table-per-Hierarchy Inheritance in Dynamic Data http://msdn.microsoft.com/en-us/library/dd793152.ASPX
Code First to an Existing Database http://msdn.microsoft.com/en-us/data/jj200620.aspx
Model-First in the Entity Framework 4 http://msdn.microsoft.com/en-us/data/ff830362.aspx
ADO.NET Entity Data Model Designer http://msdn.microsoft.com/en-us/library/vstudio/cc716685(v=vs.100).aspx
The ADO.NET Entity Framework Overview http://msdn.microsoft.com/en-us/library/aa697427(v=vs.80).aspx
ADO.NET Entity Data Model Tools http://msdn.microsoft.com/en-us/library/vstudio/bb399249(v=vs.100).aspx
Plain Old CLR Object(POCO) http://en.wikipedia.org/wiki/Plain_Old_CLR_Object
Working with POCO Entities http://msdn.microsoft.com/en-us/library/vstudio/dd456853(v=vs.100).aspx

Good to know!? C# 5.0 Key Features Reference – Part 2


This are copy notes from the main key-points found in the MS 70-483 prep book. This might be useful to someone. A checklist of things in C#.

Also check out the exam link and the actual book:


Exam Ref 70-483: Programming in C#

Implement multithreading and asynchronous processing
Using multiple threads can improve responsiveness and enables you to make use of multiple processors.
The Thread class can be used if you want to create your own threads explicitly. Otherwise, you can use the ThreadPool to queue work and let the runtime handle things.
A Task object encapsulates a job that needs to be executed. Tasks are the recommended way to create multithreaded code.
The Parallel class can be used to run code in parallel.
PLINQ is an extension to LINQ to run queries in parallel.
The new async and await operators can be used to write asynchronous code more easily.
Concurrent collections can be used to safely work with data in a multithreaded (concurrent access) environment.
Manage multithreading
When accessing shared data in a multithreaded environment, you need to synchronize
access to avoid errors or corrupted data.
 Use the lock statement on a private object to synchronize access to a piece of code.
 You can use the Interlocked class to execute simple atomic operations.
 You can cancel tasks by using the CancellationTokenSource class with a
Implement program flow
 Boolean expressions can use several operators: ==, !=, <, >, <=, >=, !. Those operators
can be combined together by using AND (&&), OR (||) and XOR (^).
 You can use the if-else statement to execute code depending on a specific condition.
 The switch statement can be used when matching a value against a couple of options.
56 Chapter 1 Manage program flow
The for loop can be used when iterating over a collection where you know the number of iterations in advance.
A while loop can be used to execute some code while a condition is true; do-while should be used when the code should be executed at least once.
foreach can be used to iterate over collections.
Jump statements such as break, goto, and continue can be used to transfer control to another line of the program.
Create and implement events and callbacks method
 Delegates can be instantiated, passed around, and invoked.
 Lambda expressions, also known as anonymous methods, use the => operator and
form a compact way of creating inline methods.
 Events are a layer of syntactic sugar on top of delegates to easily implement the
publish-subscribe pattern.
 Events can be raised only from the declaring class. Users of events can only remove
and add methods the invocation list.
 You can customize events by adding a custom event accessor and by directly using the
underlying delegate type.
Implement exception handling
 In the .NET Framework, you should use exceptions to report errors instead of error
 Exceptions are objects that contain data about the reason for the exception.
 You can use a try block with one or more catch blocks to handle different types of
 You can use a finally block to specify code that should always run after, whether or not
an exception occurred.
 You can use the throw keyword to raise an exception.
 You can define your own custom exceptions when you are sure that users of your code
will handle it in a different way. Otherwise, you should use the standard .NET Framework
Create types
 Types in C# can be a value or a reference type.
 Generic types use a type parameter to make the code more flexible.
 Constructors, methods, properties, fields, and indexer properties can be used to create
a type.
 Optional and named parameters can be used when creating and calling methods.
 Overloading methods enable a method to accept different parameters.
 Extension methods can be used to add new functionality to an existing type.
 Overriding enables you to redefine functionality from a base class in a derived class.
Consume types
 Boxing occurs when a value type is treated as a reference type.
When converting between types, you can have an implicit or an explicit conversion.
An explicit conversion is called casting and requires special syntax.
You can create your own implicit and explicit user-defined conversions.
The .NET Framework offers several helper methods for converting types.
The dynamic keyword can be used to ease the static typing of C# and to improve
interoperability with other languages.
Enforce encapsulation
Encapsulation is important in object-oriented software. It hides internal details and
improves the usability of a type.
Data can be encapsulated with a property.
Properties can have both a get and a set accessor that can run additional code, commonly
known as getters and setters.
Types and type elements can have access modifiers to restrict accessibility.
The access modifiers are public, internal, protected, protected, internal, and private.
Explicit interface implementation can be used to hide information or to implement
interfaces with duplicate member signatures.
Create and implement a class hierarchy
Inheritance is the process in which a class is derived from another class or from an interface.
An interface specifies the public elements that a type must implement.
A class can implement multiple interfaces.
A base class can mark methods as virtual; a derived class can then override those methods to add or replace behavior.
A class can be marked as abstract so it can’t be instantiated and can function only as a base class.
A class can be marked as sealed so it can’t be inherited.
The .NET Framework offers default interfaces such as IComparable, IEnumerable, IDisposable and IUnknown.
Find, execute, and create types at runtime by using reflection
A C# assembly stores both code and metadata.
Attributes are a type of metadata that can be applied in code and queried at runtime.
Reflection is the process of inspecting the metadata of a C# application.
Through reflection you can create types, call methods, read properties, and so forth.
The CodeDOM can be used to create a compilation unit at runtime. It can be compiled or converted to a source file.
Expression trees describe a piece of code. They can be translated to something else (for example, SQL) or they can be compiled and executed.
Manage the object life cycle
 Memory in C# consists of both the stack and the heap.
 The heap is managed by the garbage collector.
 The garbage collector frees any memory that is not referenced any more.
 A finalizer is a special piece of code that’s run by the garbage collector when it removes
an object.
 IDisposable can be implemented to free any unmanaged resources in a deterministic
 Objects implementing IDisposable can be used with a using statement to make sure
they are always freed.
 A WeakReference can be used to maintain a reference to items that can be garbage
collected when necessary.
Manipulate strings
A string is an immutable reference type.
When doing a lot of string manipulations, you should use a StringBuilder.
The String class offers a lot of methods for dealing with strings like IndexOf, LastIndexOf, StartsWith, EndsWith, and Substring.
Strings can be enumerated as a collection of characters.
Formatting is the process of displaying an object as a string.
You can use format strings to change how an object is converted to a string.
You can implement formatting for your own types.
Validate application input
 Validating application input is important to protect your application against both
mistakes and attacks.
 Data integrity should be managed both by your application and your data store.
 The Parse, TryParse, and Convert functions can be used to convert between types.
 Regular expressions, or regex, can be used to match input against a specified pattern
or replace specified characters with other values.
 When receiving JSON and XML files, it’s important to validate them using the built-in
types, such as with JavaScriptSerializer and XML Schemas.
Perform symmetric and asymmetric
 An asymmetric algorithm uses a public and private key that are mathematically linked.
 Hashing is the process of converting a large amount of data to a smaller hash code.
 Digital certificates can be used to verify the authenticity of an author.
 CAS are used to restrict the resources and operations an application can access and
 System.Security.SecureString can be used to keep sensitive string data in memory.
Manage assemblies
An assembly is a compiled unit of code that contains metadata.
An assembly can be strongly signed to make sure that no one can tamper with the content.
Signed assemblies can be put in the GAC.
An assembly can be versioned, and applications will use the assembly version they were developed with. It’s possible to use configuration files to change these bindings.
A WinMD assembly is a special type of assembly that is used by WinRT to map non-native languages to the native WinRT components.
Debug an application
Visual Studio build configurations can be used to configure the compiler.
 A debug build outputs a nonoptimized version of the code that contains extra instructions
to help debugging.
 A release build outputs optimized code that can be deployed to a production
 Compiler directives can be used to give extra instructions to the compiler. You can use
them, for example, to include code only in certain build configurations or to suppress
certain warnings.
 A program database (PDB) file contains extra information that is required when debugging
an application.
Implement diagnostics in an application
 Logging and tracing are important to monitor an application that is in production and
should be implemented right from the start.
 You can use the Debug and TraceSource classes to log and trace messages. By configuring
different listeners, you can configure your application to know which data to send
 When you are experiencing performance problems, you can profile your application to
find the root cause and fix it.
 Performance counters can be used to constantly monitor the health of your applications.
Perform I/O operations
 You can work with drives by using Drive and DriveInfo.
 For folders, you can use Directory and DirectoryInfo.
 File and FileInfo offer methods to work with files.
 The static Path class can help you in creating and parsing file paths.
 Streams are an abstract way of working with a series of bytes.
 There are many Stream implementations for dealing with files, network operations,
and any other types of I/O.
 Remember that the file system can be accessed and changed by multiple users at the
same time. You need to keep this in mind when creating reliable applications.
 When performing network requests, you can use the WebRequest and WebResponse
classes from the System.Net namespace.
 Asynchronous I/O can help you create a better user experience and a more scalable
Consume data
 ADO.NET uses a provider model that enables you to connect to different types of
 You use a DbConnection object to create a connection to a database.
 You can execute queries that create, update, read, and delete (CRUD) data from a
 When creating queries it’s important to use parameterized queries so you avoid SQL
Objective 4.3: Query and manipulate data and objects by using LINQ CHAPTER 4 291
You can consume a web service from your application by creating a proxy for it.
You can work with XML by using the XmlReader, XmlWriter, XPathNavigator, and XmlDocument classes.
Query and manipulate data and objects by using LINQ
 LINQ, which stands for Language Integrated Query, is a uniform way of writing queries
against multiple data sources.
 Important language features when working with LINQ queries are implicit typing, object
initialization syntax, lambdas, extension methods, and anonymous types.
 You can use LINQ with a method-based syntax and the query syntax.
 LINQ queries are deferred-execution, which means that the query executes when it is
first iterated.
 You can use LINQ to XML to query, create, and update XML.
Serialize and deserialize data
 Serialization is the process of transforming an object to a flat file or a series of bytes.
 Deserialization takes a series of bytes or a flat file and transforms it into an object.
 XML serialization can be done by using the XmlSerializer.
 You can use special attributes to configure the XmlSerializer.
 Binary serialization can be done by using the BinaryFormatter class.
 WCF uses another type of serialization that is performed by the DataContractSerializer.
 JSON is a compact text format that can be created by using the DataContractJsonSerializer.
Store data in and retrieve data from collections
 The .NET Framework offers both generic and nongeneric collections. When possible,
you should use the generic version.
 Array is the most basic type to store a number of items. It has a fixed size.
 List is a collection that can grow when needed. It’s the most-used collection.
 Dictionary stores and accesses items using key/value pairs.
 HashSet stores unique items and offers set operations that can be used on them.
 A Queue is a first-in, first-out (FIFO) collection.
 A Stack is a first-in, last-out (FILO) collection.
 You can create a custom collection by inheriting from a collection class or inheriting
from one of the collection interfaces.

Good to know!? C# 5.0 Key Features Reference – Part 1

Hi here is my reference links to C# 5.0. hope it helps someone!! 🙂

Manage program flow – Multithreading, asynchronous processing, events and callbacks, exception handling

Asynchronous Programming with Async and Await (C# and Visual Basic) http://msdn.microsoft.com/en-us/library/vstudio/hh191443.aspx
C# Operators http://msdn.microsoft.com/en-us/library/6a71f45d.aspx
CancellationTokenSource Class http://msdn.microsoft.com/en-us/library/system.threading.cancellationtokensource.aspx
Covariance and contravariance http://blogs.msdn.com/b/ericlippert/archive/tags/covariance+and+contravariance/
Delegate.GetInvocationList Method http://msdn.microsoft.com/en-us/library/system.delegate.getinvocationlist.aspx
Exceptions and Exception Handling (C# Programming Guide) http://msdn.microsoft.com/en-us/library/ms173160.aspx
Flow Control http://msdn.microsoft.com/en-us/library/hh147286%28v=vs.88%29.aspx
Interlocked Methods http://msdn.microsoft.com/en-us/library/System.Threading.Interlocked_methods.aspx
Jump Statements http://msdn.microsoft.com/en-us/library/d96yfwee.aspx
Lambda Expressions (C# Programming Guide) http://msdn.microsoft.com/en-us/library/vstudio/bb397687.aspx
lock Statement (C# Reference) http://msdn.microsoft.com/en-us/library/c5kehkcz.aspx
Parallel LINQ (PLINQ) http://msdn.microsoft.com/en-us/library/dd460688.aspx
System.Collections.Concurrent Namespace http://msdn.microsoft.com/en-us/library/system.collections.concurrent.aspx
System.Threading.Tasks Namespace http://msdn.microsoft.com/en-us/library/system.threading.tasks.aspx
Thread Class http://msdn.microsoft.com/en-us/library/system.threading.thread.aspx
ThreadLocal<T> Class http://msdn.microsoft.com/en-us/library/dd642243.aspx
ThreadPool Class http://msdn.microsoft.com/en-us/library/system.threading.threadpool.aspx
Using Delegates (C# Programming Guide) http://msdn.microsoft.com/en-us/library/ms173171%28v=vs.90%29.aspx
Volatile Class http://msdn.microsoft.com/en-us/library/system.threading.volatile.aspx

Types – Create types, Consume types, encapsulation, class hierarchy, reflection, string/text manipulation

Abstract and Sealed Classes and Class Members (C# Programming Guide) http://msdn.microsoft.com/en-us/library/ms173150.aspx
Access Modifiers (C# Reference) http://msdn.microsoft.com/en-us/library/wxh6fsc7.aspx
Anonymous Methods (C# Programming Guide) http://msdn.microsoft.com/en-us/library/0yw3tz5k.aspx
Attributes (C# and Visual Basic) http://msdn.microsoft.com/en-us/library/z0w1kczw.aspx
Basic String Operations http://msdn.microsoft.com/en-us/library/a292he7t.aspx
Best Practices for Using Strings in the .NET Framework
C# – Understanding The NET Garbage Collector http://www.csharphelp.com/2010/02/c-understandin-the-garbage-collector/
Constructor Design http://msdn.microsoft.com/en-us/library/vstudio/ms229060(v=vs.100).aspx
CultureInfo Class http://msdn.microsoft.com/en-us/library/system.globalization.cultureinfo.aspx
Enumeration Types (C# Programming Guide) http://msdn.microsoft.com/en-us/library/vstudio/cc138362.aspx
ExceptionDispatchInfo Class http://msdn.microsoft.com/en-us/library/system.runtime.exceptionservices.exceptiondispatchinfo.aspx
Expression Trees (C# and Visual Basic) http://msdn.microsoft.com/en-us/library/bb397951.aspx
Extension Methods (C# Programming Guide) http://msdn.microsoft.com/en-us/library/vstudio/bb383977.aspx
Finalize Methods and Destructors http://msdn.microsoft.com/en-us/library/0s71x931.aspx
Generics (C# Programming Guide) http://msdn.microsoft.com/en-us/library/512aeb7t.aspx
IDisposable Interface http://msdn.microsoft.com/en-us/library/system.idisposable.aspx
Immutability in C# Part One: Kinds of Immutability http://blogs.msdn.com/b/ericlippert/archive/2007/11/13/immutability-in-c-part-one-kinds-of-immutability.aspx
Interfaces (C# Programming Guide) http://msdn.microsoft.com/en-us/library/vstudio/ms173156.aspx
IUnknown interface http://msdn.microsoft.com/en-us/library/windows/desktop/ms680509%28v=vs.85%29.aspx
Managed Extensibility Framework (MEF)
Operator Keywords (C# Reference) http://msdn.microsoft.com/en-us/library/bewds7kc%28v=vs.90%29.aspx
Properties (C# Programming Guide) http://msdn.microsoft.com/en-us/library/x9fsa0sw.aspx
The Big Ball of Mud and Other Architectural Disasters http://www.codinghorror.com/blog/2007/11/the-big-ball-of-mud-and-other-architectural-disasters.html
Types (C# Programming Guide) http://msdn.microsoft.com/en-us/library/vstudio/ms173104.aspx
unsafe (C# Reference) http://msdn.microsoft.com/en-us/library/chfa2zb8.aspx
Using Conversion Operators (C# Programming Guide) http://msdn.microsoft.com/en-us/library/85w54y0a.aspx
using Statement http://msdn.microsoft.com/en-us/library/yh598w02.aspx
Using the CodeDOM http://msdn.microsoft.com/en-us/library/y2k85ax6.aspx
Using the StringBuilder Class http://msdn.microsoft.com/en-us/library/2839d5h5.aspx
Using Type dynamic (C# Programming Guide) http://msdn.microsoft.com/en-us/library/dd264736.aspx
Walkthrough: Creating and Using Dynamic Objects (C# and Visual Basic) http://msdn.microsoft.com/en-us/library/ee461504.aspx
WeakReference Class http://msdn.microsoft.com/en-us/library/system.weakreference.aspx
virtual (C# Reference) http://msdn.microsoft.com/en-us/library/9fkccyh4.aspx

Application management and development and security – Validation, encryption, assemblies, debugging, diagnostics

.NET Framework Cryptography Model http://msdn.microsoft.com/en-us/library/0ss79b2x.aspx
.NET Framework Cryptography Model http://msdn.microsoft.com/en-us/library/0ss79b2x.aspx
.NET Framework Regular Expressions http://msdn.microsoft.com/en-us/library/hs600312.aspx
Analyzing Application Performance by Using Profiling Tools http://msdn.microsoft.com/en-us/library/z9z62c29.aspx
Authenticode http://technet.microsoft.com/en-us/library/cc750035.aspx
Beginners Guide to Performance Profiling http://msdn.microsoft.com/en-us/library/ms182372.aspx
C# Preprocessor Directives http://msdn.microsoft.com/en-us/library/ed8yd1ha.aspx
Code Access Security http://msdn.microsoft.com/en-us/library/930b76w0%28v=vs.90%29.aspx
Conditional (C# Programming Guide) http://msdn.microsoft.com/en-us/library/4xssyw96%28v=vs.90%29.aspx
Debug Class http://msdn.microsoft.com/en-us/library/system.diagnostics.debug.aspx
Debugger Roadmap http://msdn.microsoft.com/en-us/library/k0k771bt.aspx
Debugging, Tracing, and Profiling http://msdn.microsoft.com/en-us/library/7fe0dd2y.aspx
EventLog Class http://msdn.microsoft.com/en-us/library/system.diagnostics.eventlog.aspx
Gacutil.exe (Global Assembly Cache Tool) http://msdn.microsoft.com/en-us/library/ex0ss12c.aspx
JavaScriptSerializer Class http://msdn.microsoft.com/en-us/library/system.web.script.serialization.javascriptserializer.aspx
Makecert.exe (Certificate Creation Tool) http://msdn.microsoft.com/en-us/library/bfsktky3%28v=vs.110%29.aspx
Object.GetHashCode Method http://msdn.microsoft.com/en-us/library/system.object.gethashcode%28v=vs.110%29.aspx
Parsing Strings http://msdn.microsoft.com/en-us/library/b4w53z0y.aspx
PDB Files (C# and Visual Basic) http://msdn.microsoft.com/en-us/library/ms241903%28v=vs.90%29.aspx
PerformanceCounter Class http://msdn.microsoft.com/en-us/library/system.diagnostics.performancecounter.aspx
Regular Expression Language – Quick Reference http://msdn.microsoft.com/en-us/library/az24scfc.aspx
Runtime Profiling http://msdn.microsoft.com/en-us/library/w4bz2147.aspx
SecureString Class http://msdn.microsoft.com/en-us/library/system.security.securestring.aspx
Sn.exe (Strong Name Tool) http://msdn.microsoft.com/en-us/library/k5b5tt23.aspx
Step 1: Examining the Configuration Files http://msdn.microsoft.com/en-us/library/8f6988ab.aspx
Stopwatch Class http://msdn.microsoft.com/en-us/library/system.diagnostics.stopwatch.aspx
Symbol Server and Symbol Stores http://msdn.microsoft.com/en-us/library/ms680693%28VS.85%29.aspx
System.ComponentModel.DataAnnotations Namespace http://msdn.microsoft.com/en-us/library/system.componentmodel.dataannotations.aspx
System.Diagnostics Namespace http://msdn.microsoft.com/en-us/library/system.diagnostics.aspx
TraceSource Class http://msdn.microsoft.com/en-us/library/system.diagnostics.tracesource.aspx
Using DebuggerDisplay Attribute http://msdn.microsoft.com/en-us/library/x810d419.aspx
XML Schema Definition Tool (Xsd.exe) http://msdn.microsoft.com/en-us/library/x6c1kb0s.aspx

Data access and manipulation – I/O operations, consume data, LINQ data manipulation, serialization, collections

101 LINQ Samples http://code.msdn.microsoft.com/101-LINQ-Samples-3fb9811b
ADO.NET Architecture http://msdn.microsoft.com/en-us/library/27y4ybxw.aspx
ADO.NET DataSets http://msdn.microsoft.com/en-us/library/zb0sdh0b.aspx
Arrays Tutorial http://msdn.microsoft.com/en-us/library/aa288453%28v=vs.71%29.aspx
BinaryFormatter Class http://msdn.microsoft.com/en-us/library/system.runtime.serialization.formatters.binary.binaryformatter.aspx
Collections (C# and Visual Basic) http://msdn.microsoft.com/en-us/library/ybcx56wz.aspx
Collections and Data Structures
ConfigurationManager Class http://msdn.microsoft.com/en-us/library/system.configuration.configurationmanager.aspx
DataContractSerializer Class http://msdn.microsoft.com/en-us/library/system.runtime.serialization.datacontractserializer.aspx
DataContractSerializer Sample http://msdn.microsoft.com/en-us/library/ms752244.aspx
DbConnection, DbCommand and DbException http://msdn.microsoft.com/en-us/library/9hy8csk1.aspx
DbConnectionStringBuilder Class http://msdn.microsoft.com/en-us/library/system.data.common.dbconnectionstringbuilder.aspx
Directory Class http://msdn.microsoft.com/en-us/library/system.io.directory.aspx
DirectorySecurity Class http://msdn.microsoft.com/en-us/library/system.security.accesscontrol.directorysecurity.aspx
DriveInfo Class http://msdn.microsoft.com/en-us/library/system.io.driveinfo.aspx
Encoding Class http://msdn.microsoft.com/en-us/library/system.text.encoding.aspx
Entity Framework http://msdn.microsoft.com/en-us/data/ef.aspx
Examples of XML Serialization http://msdn.microsoft.com/en-us/library/58a18dwa.aspx
File Class http://msdn.microsoft.com/en-us/library/system.io.file.aspx
FileInfo Class http://msdn.microsoft.com/en-us/library/system.io.fileinfo.aspx
FileStream Class http://msdn.microsoft.com/en-us/library/system.io.filestream.aspx
Getting Started with LINQ in C# http://msdn.microsoft.com/en-us/library/bb397933.aspx
How to: Extend the Async Walkthrough by Using Task.WhenAll (C# and Visual Basic) http://msdn.microsoft.com/en-us/library/vstudio/hh556530.aspx
How to: Parse XML with XmlReader http://msdn.microsoft.com/en-us/library/cc189056%28v=vs.95%29.aspx
HttpClient Class http://msdn.microsoft.com/en-us/library/system.net.http.httpclient.aspx
Implementing an Implicit Transaction using Transaction Scope http://msdn.microsoft.com/en-us/library/ee818746.aspx
MemoryStream Class http://msdn.microsoft.com/en-us/library/system.io.memorystream.aspx
NonSerializedAttribute Class http://msdn.microsoft.com/en-us/library/system.nonserializedattribute.aspx
Parameters and Execution Plan Reuse http://msdn.microsoft.com/en-us/library/ms175580.aspx
Path Class http://msdn.microsoft.com/en-us/library/system.io.path.aspx
Retrieving and Modifying Data in ADO.NET http://msdn.microsoft.com/en-us/library/ms254937.aspx
Serialization (C# and Visual Basic) http://msdn.microsoft.com/en-us/library/vstudio/ms233843.aspx
SQL Injection http://msdn.microsoft.com/en-us/library/ms161953%28v=sql.105%29.aspx
SqlCommand Class http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.aspx
SqlConnection Class http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlconnection.aspx
SqlDataReader Class http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqldatareader.aspx
StreamReader Class http://msdn.microsoft.com/en-us/library/system.io.streamreader.aspx
StreamWriter Class http://msdn.microsoft.com/en-us/library/system.io.streamwriter.aspx
System.IO.Compression Namespace http://msdn.microsoft.com/en-us/library/system.io.compression.aspx
System.Net Namespace http://msdn.microsoft.com/en-us/library/system.net.aspx
Using Data Contracts http://msdn.microsoft.com/en-us/library/ms733127.aspx
Using the DbContext API http://msdn.microsoft.com/en-us/data/gg192989%28v=msdn.10%29.aspx
var (C# Reference) http://msdn.microsoft.com/en-us/library/bb383973.aspx
Web.config Transformation Syntax for Web Project Deployment Using Visual Studio http://msdn.microsoft.com/en-us/library/dd465326.aspx
WebRequest Class http://msdn.microsoft.com/en-us/library/system.net.webrequest.aspx
WebResponse Class http://msdn.microsoft.com/en-us/library/system.net.webresponse.aspx
What Is Windows Communication Foundation http://msdn.microsoft.com/en-us/library/ms731082.aspx
XML Standards Reference http://msdn.microsoft.com/en-us/library/ms256177.aspx
XmlAttributes.XmlArray Property http://msdn.microsoft.com/en-us/library/system.xml.serialization.xmlattributes.xmlarray.aspx
XmlAttributes.XmlArrayItems Property http://msdn.microsoft.com/en-us/library/system.xml.serialization.xmlattributes.xmlarrayitems.aspx
XmlAttributes.XmlAttribute Property http://msdn.microsoft.com/en-us/library/system.xml.serialization.xmlattributes.xmlattribute.aspx
XmlAttributes.XmlElements Property http://msdn.microsoft.com/en-us/library/system.xml.serialization.xmlattributes.xmlelements.aspx
XmlAttributes.XmlIgnore Property http://msdn.microsoft.com/en-us/library/system.xml.serialization.xmlattributes.xmlignore.aspx
XmlDocument http://msdn.microsoft.com/en-us/library/system.xml.xmldocument.aspx
XmlReader http://msdn.microsoft.com/en-us/library/system.xml.xmlreader.aspx
XmlSerializer Class http://msdn.microsoft.com/en-us/library/system.xml.serialization.xmlserializer.aspx
XmlWriter http://msdn.microsoft.com/en-us/library/system.xml.xmlwriter.aspx
XPathNavigator http://msdn.microsoft.com/en-us/library/system.xml.xpath.xpathnavigator.aspx

Other important links:

ENTITY FRAMEWORK http://msdn.microsoft.com/en-us/data/ef.aspx
Visual Studio Plugins http://www.nuget.org/
Database ConnectionStrings http://www.connectionstrings.com/
Json.NET http://json.codeplex.com/
LINQPad http://www.linqpad.net/