在VS 2012项目中启用System.Net.Http

Question

I'm fairly new to JSON development and just getting started is a major task with very little in the way of solutions via Google.

I can't get anywhere without adding system.net.http as part of my project

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web;
using System.Net.Http;

objects like var, HttpWebClient, KeyValuePair throw up an error during compile. Here's what I tried:

• Reinstalled .NET 4.0
• Reinstalled .NET 4.5
• Repackaged library via. NuGet
• Referenced system.net

No luck. I've even tried referencing the the class in web.config

<compilation targetFramework="4.5">
  <assemblies>
    <add assembly="System.Net.Http, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
  </assemblies>
</compilation>

and again in..

<runtime>
  <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
    <dependentAssembly>
      <assemblyIdentity name="System.Net.Http" publicKeyToken="b03f5f7f11d50a3a" />
      <bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.0.0.0" />
    </dependentAssembly>
  </assemblyBinding>
</runtime>

An error is thrown on "assemblies"

I'm at my wits end. What am I not referencing or doing wrong where System.Net.Http cannot be used.

Answer 1

In .NET 4.5 System.Net.Http is in it's own assembly, you have to go to "Add References" (right click on the project) and select it.

See the MSDN page for HttpClient: http://msdn.microsoft.com/en-us/library/system.net.http.httpclient.aspx

Assembly: System.Net.Http (in System.Net.Http.dll)

Answer 2

The help system reveals that the System.Net.Http namespace is defined in System.Net.Http.dll which as you say is not listed. A quick search of my own filesystem reveals copies

• In the GAC
• In the framework folders for both 32 and 64 bit

On my system those paths are

 C:\Windows\Microsoft.NET\Framework\v4.0.30319
 C:\Windows\Microsoft.NET\Framework64\v4.0.30319

System.Net.Http.WebRequest.dll is on the same paths.

Answer 3

Did you try

using System.Net.Http;

C# is a case-sensitive language.