System.ServiceModel missing

I'm working with VS2010 express on Win7 (64 bit) and I'm trying use System.ServiceModel but I get an error that there is no ServiceModel in the System namespace:

The type or namespace name 'ServiceModel' does not exist in the namespace 'System' 开发者_C百科(are you missing an assembly reference?)

I looked in \Windows\Microsoft.NET\Framework\v4.0.30319 and there are some ServiceModel___.dll files but I don't know if I'm missing something or if they are corrupted.

Any advice?

Thanks, Yonatan

Add a reference to the assembly System.ServiceModel. Select Project-> Add Reference and then select the assembly name.

Right click on Project -> Properties -> Application -> Target Framework = .NET Framework 4.5

The System.ServiceModel namespace is in System.ServiceModel.dll.

I'm not running 64 bit Windows so I can't check whether that's the right location.

Sometimes Visual Studio doesn't install this dll in GAC.
You can gac what is located in %systemDrive%\Windows\Microsoft.NET\Framework\v4.0.30319 using gacutil /i dll_file
To use gacutil you can open Command Prompt from Visual Studio Tools menu.