C#DataGridView合并第一行前3列单元格并且居中

您可以使用以下代码来合并第一行前3列单元格并居中显示：

private void MergeCells()
{
    // 合并前3列的单元格
    dataGridView1.Rows[0].Cells[0].Value = "合并测试";
    dataGridView1.Rows[0].Cells[0].Style.Alignment = DataGridViewContentAlignment.MiddleCenter;
    dataGridView1.Rows[0].Cells[1].Value = "";
    dataGridView1.Rows[0].Cells[2].Value = "";
    dataGridView1.Rows[0].Cells[3].Value = "单元格4";
    dataGridView1.Rows[0].Cells[4].Value = "单元格5";
    dataGridView1.Rows[0].Cells[5].Value = "单元格6";
    dataGridView1.Rows[0].Cells[0].Style.BackColor = Color.LightGray;
    dataGridView1.Rows[0].Cells[1].Style.BackColor = Color.LightGray;
    dataGridView1.Rows[0].Cells[2].Style.BackColor = Color.LightGray;
    dataGridView1.Rows[0].Cells[3].Style.BackColor = Color.LightGray;
    dataGridView1.Rows[0].Cells[4].Style.BackColor = Color.LightGray;
    dataGridView1.Rows[0].Cells[5].Style.BackColor = Color.LightGray;
    dataGridView1.Rows[0].Cells[0].Style.Font = new Font("微软雅黑", 14, FontStyle.Bold);
    dataGridView1.Rows[0].Cells[0].Style.SelectionBackColor = Color.LightGray;
    dataGridView1.Rows[0].Cells[0].Style.SelectionForeColor = Color.Black;
    dataGridView1.Rows[0].Cells[0].Style.WrapMode = DataGridViewTriState.True;
    dataGridView1.Rows[0].Cells[0].Style.Padding = new Padding(5, 5, 5, 5);
    dataGridView1.Rows[0].Cells[0].Style.Alignment = DataGridViewContentAlignment.MiddleCenter;
    dataGridView1.Rows[0].Cells[1].Style.Padding = new Padding(5, 5, 5, 5);
    dataGridView1.Rows[0].Cells[2].Style.Padding = new Padding(5, 5, 5, 5);
    dataGridView1.Rows[0].Cells[3].Style.Padding = new Padding(5, 5, 5, 5);
    dataGridView1.Rows[0].Cells[4].Style.Padding = new Padding(5, 5, 5, 5);
    dataGridView1.Rows[0].Cells[5].Style.Padding = new Padding(5, 5, 5, 5);

    dataGridView1.Rows[0].Cells[0].Selected = false;
    dataGridView1.Rows[0].Cells[1].Selected = false;
    dataGridView1.Rows[0].Cells[2].Selected = false;
}

请注意，此代码将第一行前3列单元格合并，并将其文本居中对齐，将单元格背景色设置为浅灰色，并将字体加粗。您可以根据需要进行修改。