Control width in grid, when in batch edit mode

[Jacek]

How can I set width of textbox, dropdown in edit mode while batch editing?
This code is not working :
        protected void RadGrid1_ItemDataBound(object sender, GridItemEventArgs e)
        {
            if ((e.Item is GridEditFormItem) && (e.Item.IsInEditMode))
            {
                GridEditFormItem editItem = (GridEditFormItem)e.Item;
                TextBox txtbx = (TextBox)editItem["LVL"].Controls[0];
                txtbx.Width = Unit.Pixel(20);
            }
        }
I dont want to have half of textbox visible, example in attachment.

[Jacek]

I have solution :
        protected void RadGrid1_PreRender(object sender, EventArgs e)
        {
            TextBox x = (RadGrid1.MasterTableView.GetBatchColumnEditor("LVL") as GridTextBoxColumnEditor).TextBoxControl;
            x.Width = Unit.Pixel(20);
        }