關於VS2005 WinForm下DataGridView單元格合並，背景色設置

最近發現這方面在社區內提問的不少，發個源代碼，嘿嘿

        private void Form1_Load(object sender, EventArgs e)
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("A");
            dt.Columns.Add("B");
            dt.Columns.Add("C");
            dt.Columns.Add("D");
            dt.Rows.Add(new object[] { "A1", "B1", "C1", "D1" });
            dt.Rows.Add(new object[] { "A2", "B2", "C2", "D2" });
            dt.Rows.Add(new object[] { "A3", "B3", "C3", "D3" });
            this.dataGridVIEw1.DataSource = dt;

        }

        private void dataGridView1_CellPainting(object sender, DataGridVIEwCellPaintingEventArgs e)
        {

            if (e.RowIndex < 0 || e.RowIndex >= this.dataGridVIEw1.Rows.Count - 1 || e.ColumnIndex == -1)
            {
                return;
            }

            // 假定需要將C列值為C3的單元格與前一單元格合並
            if (e.ColumnIndex == 1 && this.dataGridVIEw1[e.RowIndex, e.ColumnIndex + 1].Value.ToString() == "C3")