GridView绑定DataTable后怎么合并连续相同的列

GridView绑定DataTable后怎样合并连续相同的列
如题，我试了两种方法了都不行。
绑定代码

需要制作的效果：（将红框内的单元格合并，并且显示汉字）

                                                              
                 
[解决办法]
http://www.cnblogs.com/nianming/archive/2012/10/10/2719103.html
[解决办法]
分两次合并就可以了
[解决办法]
 protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        foreach (TableCell tc in e.Row.Cells)
        {
            tc.Attributes["style"] = "border-color:Black";
        }
        if (e.Row.RowIndex != -1)
        {
            int id = GridView1.PageIndex * GridView1.PageSize + e.Row.RowIndex + 1;
            e.Row.Cells[0].Text = id.ToString();
        }
    }


private void gvRender()
    {
        if (GridView1.Rows.Count <= 1)
        {
            return;
        }
        for (int i = 0; i < GridView1.Columns.Count; i++)
        {
            TableCell oldtc = GridView1.Rows[0].Cells[i];
            for (int j = 1; j < GridView1.Rows.Count; j++)
            {
                TableCell newtc = GridView1.Rows[j].Cells[i];
                if (newtc.Text == oldtc.Text)
                {
                    newtc.Visible = false;
                    if (oldtc.RowSpan == 0)
                    {
                        oldtc.RowSpan = 1;
                        oldtc.RowSpan = oldtc.RowSpan + 1;
                        oldtc.VerticalAlign = VerticalAlign.Middle;
                    }
                    else
                    {
                        oldtc = newtc;
                    }
                }
            }
        }
    }