By working with temporary projects, you can create and experiment with a project without specifying a disk location. When you create a temporary project, you specify only a project type, a template, and a name in the New Project dialog box. You can save or discard a temporary project at any time while you are working with it.
All Visual Basic and Visual C# projects can be created as temporary projects. If you want to work with temporary projects, open the Tools menu, choose Options, choose Project Solutions, and then, in the General dialog box, clear the Save new projects when created check box.
A solution can contain only one temporary project at a time. Therefore, if you want to add a temporary project to a solution that already contains one, you will be prompted to save the existing temporary project first. While you are working with a temporary project, you can close and reopen project items without saving them. However, you can save a project item in a temporary project at any time while you are working with the project. The project item represents a link to the saved file. If you later save the temporary project, that saved item remains a linked file, and a copy is not saved in the project folder. If you delete a file from a temporary project, the file is deleted permanently and cannot be saved if you later save the project.