Referanslara System.Core Ekleme

Referencing System.Core
Create new .NET 2.0 project just like in the previous section.
Right-click on the project in Solution Explorer and select "Unload Project"
Right-click on the project again again and select "Edit [ProjectName]". You should see XML document now.
Find the references section that could look like this:

<reference include="System">
<reference include="System.Data">
<reference include="System.Xml">

Manually append reference to System.Core.dll:

<reference include="System.Core">
<private>True</private>
</reference>
Save.

Right-click on the project in Solution Explorer again and select "Reload"
Congratulations. You can now use some .NET 3.5 features in your project, while still having a .NET 2.0 requirement.