I wanted to test my sharepoint application using console application using VisualStudio 2010. I was able to add the reference to "Microsoft.SharePoint" dll. But while compling the code, the compiler was throwing error. To resolve this issue
make the followinf changes:
1) Select ".Net Framework 3.5" in the New Project Dialog Window while creating a new project.
2) For existing project follow this: Go to the Application tab of project properties and verify that .NET Framework Version 3.5 is select as the Target Framework.
3) Change the configuration manager to "x64". This can be done by: Go to Configuration Manager, Select x64.
4) If x64 is not available select <New…> and in the New Solution Platform dialog box select x64 as the new platform copying settings from x86 and checking the Create new project platforms check box.
hope this helps!