DataGridView的DataGridViewComboBoxColumn列点击一次，自动处于编辑状态

private void IniteDGV()
        {
            DataGridViewComboBoxColumn combo = new DataGridViewComboBoxColumn();
            combo.HeaderText = "comboBox列";
            combo.Name = "combo";
            combo.Width = 80;
            combo.DataSource=(new string[] { "0", "1", "2" });

            DataGridViewTextBoxColumn textbox = new DataGridViewTextBoxColumn();
            textbox.HeaderText = "textbox列";
            textbox.Name = "textbox";
            textbox.Width = 100;

            dataGridView.Columns.AddRange(combo, textbox);
            DataGridViewRow row = new DataGridViewRow();
            dataGridView.Rows.Add(row);



            if (dataGridView.Columns.Contains("combo") )
            {
                row.Cells["combo"].Value = "0";
            }

 }

CellClick事件
private void dataGridView_CellClick(object sender, DataGridViewCellEventArgs e)
        {
            if (e.RowIndex >= 0 && e.ColumnIndex >= 0)
            {
                DataGridViewComboBoxColumn combo = dataGridView.Columns[e.ColumnIndex] as DataGridViewComboBoxColumn;
                if (combo != null)  //如果该列是ComboBox列
                {
                    dataGridView.BeginEdit(false); //结束该列的编辑状态
                    DataGridViewComboBoxEditingControl comboEdite = dataGridView.EditingControl as DataGridViewComboBoxEditingControl;
                    if (comboEdite != null)
                    {
                        comboEdite.DroppedDown = true; //展现下拉列表
                    }
                }


                DataGridViewTextBoxColumn textbox = dataGridView.Columns[e.ColumnIndex] as DataGridViewTextBoxColumn;
                if (textbox != null) //如果该列是TextBox列
                {
                    dataGridView.BeginEdit(true); //开始编辑状态
                }
            }
        }

CellEnter事件
private void dataGridView_CellEnter(object sender, DataGridViewCellEventArgs e)
        {
            DataGridView dgv = sender as DataGridView;

            if (dgv != null)
            {
                if (dgv.Columns[e.ColumnIndex].Name == "combo" &&
                   dgv.Columns[e.ColumnIndex] is DataGridViewComboBoxColumn)
                {
                    SendKeys.Send("{F4}"); //选中ComboBox列时，相当于按了键盘的F4键
                }
            }
        }