Count of selection files in the Folder using C#.net

Question

Hi,
    How can i [B]count of Selection file in the C#.net?[/B]  .
[B]For Example :[/B] 
In my project ,I am using [B]"RegEdit"[/B] ,that means Windows Registry.
1) User could select a File/Files from any folders
2) Click on the File.User could view the [B]Count of selection of file in the Folder[/B]
Please Help me.