Debugging the Code To debug your code 1 Open the SharePoint page that contains the listview or list form web parts that contains the custom action. 2 Open your project's solution using Visual Studio. 3 Select Debug | Attach to Process. 4 Select w3wp.exe in the process list. If w3wp.exe is not listed, make sure that you check Show processes in all sessions. You may see more than one w3wp.exe listed. If you do, select the one with your user name. 5 Click Attach. 6 Set some breakpoints in your custom action code. 7 Invoke your custom action by clicking the custom toolbar button or the custom context menu that you configure in the listview or the list form web part.