[c#] ado.net - datagrid - disable-ovanje kolona

Code:

private void formatiraj_dg()
        {
            
            
        
            DataGridTableStyle s=new DataGridTableStyle();
            s.MappingName = "IZDATO";
            DataGridTextBoxColumn d1=new DataGridTextBoxColumn();
            DataGridTextBoxColumn d2=new DataGridTextBoxColumn();
            DataGridTextBoxColumn d3=new DataGridTextBoxColumn();
            DataGridTextBoxColumn d4=new DataGridTextBoxColumn();
            d1.MappingName = "ID";
            d1.Width = 0;

            d2.MappingName = "IDK";
            d2.HeaderText = "ID Kupca";
            d2.Width = 65;
            d2.Alignment = HorizontalAlignment.Center;
            d2.TextBox.Enabled = true;
            

            d3.MappingName = "IDF";
            d3.HeaderText = "ID Film";
            d3.Width = 65;
            d3.Alignment = HorizontalAlignment.Center;
            d3.TextBox.Enabled = true;

            d4.MappingName = "Datum";
            d4.HeaderText = "Datum";
            d4.Width = 80;
            d4.Alignment = HorizontalAlignment.Center;
            d4.NullText = "";
            d3.TextBox.Enabled = true;
            d4.Format = "dd-MM-yyyy";

            s.GridColumnStyles.Add(d1);
            s.GridColumnStyles.Add(d2);
            s.GridColumnStyles.Add(d3);
            s.GridColumnStyles.Add(d4);
            dataGrid1.TableStyles.Add(s);
        
        
        
        }