title: Why doesn't DataDirectory change on run time
body: <p>I am tring to connect to a local database with w winform c# application 
  when i set my connection string to Data: <code>Source=C:\Users\PACKARD BELL\documents\visual studio 2010\Projects\GestionStock\MyApp\Mydb.sdf</code><br>
  it works fine but when i set it to <code>Data Source=|DataDirectory|\Mydb.sdf</code> it dosen't work 
  i tried to print the connection string with the data directory variable in the console and i found that it dosen't change </p>
  
  <p>i want the connection string to change with the location of the application folder </p>
  
  <p>How can i do that?
  thanks in advance </p>