How to Make CheckBox Checked in Gridview Raw when the Text box have value

hi i have a grid view and i want to make the check box inside one of the colums to be checked only if the text box have somthing on it, the below is wht i have so far but its not working !!

foreach (GridViewRow gvr in GridView1.Rows) { TextBox D1R = (TextBox)gvr.FindControl("TextBox1"); CheckBox D1C = (CheckBox)gvr.FindControl("CheckBox1"); if (D1R.Text.Length > 0) { D1C.Checked = true; }