How to get Visual Studio 2010 to use .NET 4.0 instead of .NET 2.0 in a Windows Phone project?

Question

This is a Windows Phone 7 project.

For some strange reason, Visual Studio 2010 will not allow me to install the target version of .NET in .NET 4.0 in the project settings, the Application tab. It is inactive.

When I compile the project, the XNA assemblies make up .NET 4.0, but System and System.Core and all the rest are .NET 2.0.

When I say Add Link, it will not let me select any of the .NET 4.0 system assemblies, such as mscorlib.

I uninstalled .NET 4.0 and reinstall it. No help.

Edit: My ultimate goal is to put this together. Why does he choose .NET 2.0 to build the system?

Edit: I get the following errors:

C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets(1360,9): warning MSB3268: The primary reference "Microsoft.Xna.Framework.Video" could not be resolved because it has an indirect dependency on the framework assembly "mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" which could not be resolved in the currently targeted framework. ".NETFramework,Version=v4.0,Profile=Client". To resolve this problem, either remove the reference "Microsoft.Xna.Framework.Video" or retarget your application to a framework version which contains "mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089". C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets(1360,9): warning MSB3268: The primary reference "Microsoft.Xna.Framework.Net" could not be resolved because it has an indirect dependency on the framework assembly "mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" which could not be resolved in the currently targeted framework. ".NETFramework,Version=v4.0,Profile=Client". To resolve this problem, either remove the reference "Microsoft.Xna.Framework.Net" or retarget your application to a framework version which contains "mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089". C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets(1360,9): warning MSB3268: The primary reference "Microsoft.Xna.Framework.Avatar" could not be resolved because it has an indirect dependency on the framework assembly "mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" which could not be resolved in the currently targeted framework. ".NETFramework,Version=v4.0,Profile=Client". To resolve this problem, either remove the reference "Microsoft.Xna.Framework.Avatar" or retarget your application to a framework version which contains "mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089". C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets(1360,9): warning MSB3268: The primary reference "Microsoft.Xna.Framework.Storage" could not be resolved because it has an indirect dependency on the framework assembly "mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" which could not be resolved in the currently targeted framework. ".NETFramework,Version=v4.0,Profile=Client". To resolve this problem, either remove the reference "Microsoft.Xna.Framework.Storage" or retarget your application to a framework version which contains "mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089". C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets(1360,9): warning MSB3268: The primary reference "Microsoft.Xna.Framework.Xact" could not be resolved because it has an indirect dependency on the framework assembly "mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" which could not be resolved in the currently targeted framework. ".NETFramework,Version=v4.0,Profile=Client". To resolve this problem, either remove the reference "Microsoft.Xna.Framework.Xact" or retarget your application to a framework version which contains "mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089". C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets(1360,9): warning MSB3268: The primary reference "Microsoft.Xna.Framework.Net" could not be resolved because it has an indirect dependency on the framework assembly "System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" which could not be resolved in the currently targeted framework. ".NETFramework,Version=v4.0,Profile=Client". To resolve this problem, either remove the reference "Microsoft.Xna.Framework.Net" or retarget your application to a framework version which contains "System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089". C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets(1360,9): warning MSB3268: The primary reference "Microsoft.Xna.Framework.Xact" could not be resolved because it has an indirect dependency on the framework assembly "System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" which could not be resolved in the currently targeted framework. ".NETFramework,Version=v4.0,Profile=Client". To resolve this problem, either remove the reference "Microsoft.Xna.Framework.Xact" or retarget your application to a framework version which contains "System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089". C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets(1360,9): warning MSB3268: The primary reference "Microsoft.Xna.Framework.Xact" could not be resolved because it has an indirect dependency on the framework assembly "System.Core, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" which could not be resolved in the currently targeted framework. ".NETFramework,Version=v4.0,Profile=Client". To resolve this problem, either remove the reference "Microsoft.Xna.Framework.Xact" or retarget your application to a framework version which contains "System.Core, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089". C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets(1360,9): warning MSB3268: The primary reference "Microsoft.Xna.Framework.Xact" could not be resolved because it has an indirect dependency on the framework assembly "Microsoft.VisualC, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" which could not be resolved in the currently targeted framework. ".NETFramework,Version=v4.0,Profile=Client". To resolve this problem, either remove the reference "Microsoft.Xna.Framework.Xact" or retarget your application to a framework version which contains "Microsoft.VisualC, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a". 

Edit: OK, I uninstalled these abusive XNA assemblies. It turned out that I did not need them. Now the compiler returns to this error:

 error CS0518: Predefined type 'System.Object' is not defined or imported Compile complete -- 1 errors, 0 warnings 

Answer 1

Visual Studio shows you the correct builds. You cannot select .NET 4.0 assemblies for Windows Phone 7 for the simple reason that Windows Phone 7 does not run .NET 4.0.

The versions you see should be like this:

• Microsoft.Phone. * - 7.0.0.0
• Microsoft.XNA * - 4.0.0.0
• mscorelib - 2.0.5.0
• System. * - 2.0.5.0

Answer 2

Windows Phone uses Silverlight (Silverlight 3 for 7.0, Silverlight 4 for Mango), which does not work with the full .NET CLR, but uses a subset of the full .NET CLR (see MSDN links to Silverlight on Windows Phone , Silverlight Architecture ). Therefore, you cannot use .NET 4.0 assemblies or even complete .NET 2.0 assemblies.

The version numbers 2.0.5.0 that you can see are special Silverlight version numbers - this is not really a complete .NET 2.0 build.

However, this means that you can add Silverlight assemblies to Windows Phone (for example, this is what you do for the Silverlight Unit Test environment). If you do this, you will receive a warning that not all Silverlight desktops are supported on Windows Phone. You should only do this with caution, as everything may break ...

Answer 3

Check if you are using the .NET platform or the .NET Framework client profile. If this is a client profile, change it to the .NET Framework.