You can easily access to special directories of windows in C# by using:

Environment.SpecialFolder.MyDocuments;

The same go with other directories

Environment.SpecialFolder.Desktop;
Environment.SpecialFolder.History;
…

Application paths in C#.net
Application.ExecutablePath
return C:\projects\test\bin\debug\run.exe
Application.StartupPath
return C:\projects\test\bin\debug

Common selectors to choose all internal or external links

Find in the database all the store procedures using specific tables or views.
Or list all the tables or view, which the specific Views or StoreProcudres use.

Check the input string if it’s in correct email format or not.