asp.net 合并GridView中某列相同信息的行（单元格）

/// <summary>
/// 合并GridView中某列相同信息的行（单元格）
/// </summary>
/// <param name="GridView1">GridView</param>
/// <param name="cellNum">第几列</param>
public static void GroupRows(GridView GridView1, int cellNum)
{
int i = 0, rowSpanNum = 1;
while (i < GridView1.Rows.Count - 1)
{
GridViewRow gvr = GridView1.Rows[i];

for (++i; i < GridView1.Rows.Count; i++)
{
GridViewRow gvrNext = GridView1.Rows[i];
if (gvr.Cells[cellNum].Text == gvrNext.Cells[cellNum].Text)
{
gvrNext.Cells[cellNum].Visible = false;
rowSpanNum++;
}
else
{
gvr.Cells[cellNum].RowSpan = rowSpanNum;
rowSpanNum = 1;
break;
}

if (i == GridView1.Rows.Count - 1)
{
gvr.Cells[cellNum].RowSpan = rowSpanNum;
}
}
}
}