System.Web.Http is missing after a .NET 4.5 upgrade

Question

I've just upgraded my solution to .NETE 4.5 using Target Framework Migrator, and then the package manager console command:

Update-Package -Reinstall -IgnoreDependencies

In one of my projects I am using:

using System.Web.Http.Controllers;
using System.Web.Http.Filters;

The code uses HttpActionContext and ReflectedHttpActionDescriptor. I notice that System.Web.Http has been removed from my references, and is no longer available in the Add New Reference window. What's going on?

Hi, this should help... http://stackoverflow.com/questions/9611316/system-net-http-missing-from-namespace-using-net-4-5 O — , Jan 07 '15 at 12:07
are you targeting the 4.5 Client Profile instead of the full framework maybe? — , Jan 07 '15 at 12:17

score 81 · Accepted Answer · edited Mar 03 '23 at 12:50

81

Look in the Extensions part of the "Add new reference", instead of Framework.

If it's not there, it's in the Microsoft.AspNet.WebApi.Core package on NuGet.

edited Mar 03 '23 at 12:50

Peter Mortensen

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answered Jan 07 '15 at 12:08

Steen Tøttrup

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Yes, I see that it's under Extensions now. – Kev Jan 07 '15 at 14:36
8

No. It isn't. Microsoft Visual Studio likes to move things around so much it might have been there at some point. It no longer is. – sn0r Aug 06 '18 at 10:59

score 33 · Answer 2 · edited Mar 03 '23 at 12:46

33

As for Visual Studio 2017, as said in the ASP.NET forums, Microsoft has moved the namespace to a NuGet package called Web API Core.

In order to install it, you need to typeInstall-Package Microsoft.AspNet.WebApi.Core in the NuGet Package Manager Console.

edited Mar 03 '23 at 12:46

Peter Mortensen

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answered Jun 11 '17 at 17:59

Ezra Steinmetz

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Just for everybody information, it works also with VS2015. Thanks! – Andrea Girardi Jan 31 '18 at 15:38
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This fixed my build with a new machine and VS 2019 – Skip Saillors Jan 21 '20 at 17:35

score 2 · Answer 3 · edited Mar 03 '23 at 12:49

2

Just run the following NuGet command:

Install-Package Microsoft.AspNet.WebApi.Core

edited Mar 03 '23 at 12:49

Peter Mortensen

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answered Dec 04 '19 at 06:24

Vinay Patel

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Thanks! This worked for me too. This added `System.Web.Http` version 5.2.7.0 to my App.config file. – benjaminoerskov Jun 03 '21 at 11:37

score 1 · Answer 4 · edited Mar 03 '23 at 12:49

1

I did this:

Update-Package -Reinstall

And it helped my project be well done.

edited Mar 03 '23 at 12:49

Peter Mortensen

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answered Feb 12 '20 at 22:54

Igor Podolskiy

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System.Web.Http is missing after a .NET 4.5 upgrade

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