The default working directory for the ASP.NET Development Server is a directory under your Visual Studio install root. If you installed Visual Studio in C:\Program Files. Your ASP.NET Development Server working directory would be C:\Program Files\Common Files\Microsoft Shared\DevServer\10.0.
To get the location of working directory using GetCurrentDirectory() method. This method is exist in System.IO.Directory class.
To set the location of working direcotry using SetCurrentDirectory() method. This method is exist in System.IO.Directory class.
Here are sample example :
//Set New current directory
lblNewCurrentDirectory.Text = System.IO.Directory.GetCurrentDirectory();