Having said that this doesn't look right

DataGrid1.EditItemIndex = -1
BindGrid()
DataGrid1.EditItemIndex = objARgs.Item.ItemIndex

it should be

DataGrid1.EditItemIndex = -1
DataGrid1.EditItemIndex = objARgs.Item.ItemIndex
BindGrid()

else you don't bind till th enext time round, well you do, but you bind to -1.

In your current code  click the same edit button  twice and it will work  ( I
suspect).