Hi, I try to add sharepoint reference in my c# project, but I keep got error The type or namespace name 'SharePoint' does not exist in the namespace 'Microsoft' (are you missing an assembly reference?) I already add the reference under the References document, and install the sharepoint foundation. The reference add path is C:\Program Files\Common Files\Microsoft Shared\web server extensions\14\ISAPI I tried all the solution in internet, but still can't figure it out. Thanks for help.