Merge Header - Gridview/DataGrid

protected void GridView_Merge_Header_RowCreated(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.Header)
{
//Build custom header.
GridView oGridView = (GridView)sender;
GridViewRow oGridViewRow = new GridViewRow(0, 0, DataControlRowType.Header, DataControlRowState.Insert);
TableCell oTableCell = new TableCell();

//Add Department
oTableCell.Text = "Department";
oTableCell.ColumnSpan = 2;
oGridViewRow.Cells.Add(oTableCell);

//Add Employee
oTableCell = new TableCell();
oTableCell.Text = "Employee";
oTableCell.ColumnSpan = 3;
oGridViewRow.Cells.Add(oTableCell);
oGridView.Controls[0].Controls.AddAt(0, oGridViewRow);
}
}