I am using webDataGrid v10.1,In my Project ,I Write Code like this:

  public void SetAllCheckControlState(bool isChecked)
        {
            foreach (Infragistics.Web.UI.GridControls.GridRecord ugRow in this.Rows)
            {  CheckBox chbCheck = ugRow.FindControl(CheckControlColumnName) as CheckBox;
                if (chbCheck.Checked != isChecked && chbCheck.Enabled)
                {
                    chbCheck.Checked = isChecked;
                }
            }
        }

the  CheckBox chbCheck = ugRow.FindControl(CheckControlColumnName) as CheckBox;
always Return null,Can any one help me ?