I'm editing records in a datagrid (one at a time). Everytings works fine, but now I have to validate the input of the user.

First of all you have the client-side :

I tried the validation controls on the datagrid template columns. This worked, but the grid turned out extremly ugly because it has to allow room for the validation control as well as the textbox Is there an another way to do this f.e. outside the datagrid or what do experts do ?

And the server-side validation : how can this been performed ?