how to show all chacters of a string before the @ character

Hi ive got the following qustion.

I have a an asp.net gridview. and one colum contains the user. However all the users have a

certain const value at the end like @blabla wich i dont want to show in the gridview colum

so user was pietje@blabla and i want to show just pietje.

I have got the following itemtemplate to show the hole user, but how can i remove the chachagters after the '@' ??

This is what i got already.