Grid Panel Selection Model

Question

Hi All ,

I have tried this example and it doesn't work with me

http://examples.ext.net/#/GridPanel/Selection_Models/Checkbox_Selection/

I'm using version 0.8 , what i want to do to make CheckboxSelection and When I select some rows and click on delete button , I will go to delete the selected rows from the database

in the Ajax Handler of the delete button the SelectedRows.Count = 0

please help me as soon as you can

Thanks in Advance