试试这个。
private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
        {
            ComboBox nameComboBox = e.Control as ComboBox;
            if (dataGridView1.CurrentCell.ColumnIndex == 0)
            {
                if (nameComboBox != null)
                {
                    ((ComboBox)e.Control).DropDownStyle = ComboBoxStyle.DropDown;
                    ((ComboBox)e.Control).AutoCompleteSource = AutoCompleteSource.ListItems;
                    ((ComboBox)e.Control).AutoCompleteMode = System.Windows.Forms.AutoCompleteMode.Suggest;
                nameComboBox .SelectedIndexChanged -= (nameComboBox _SelectedIndexChanged);
                nameComboBox .SelectedIndexChanged += (nameComboBox _SelectedIndexChanged);
                }
            }
        }
    private void nameComboBox_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (dataGridView1.CurrentCell.ColumnIndex == 1)
        {
        var rowindex = dataGridView1.CurrentCell.RowIndex;
              if (dataGridView1[1, rowindex].EditedFormattedValue != null)
              {
                  Consol.WriteLine(dataGridView1[1, rowindex].EditedFormattedValue.ToString());
              }
              else
              {
                 //No value in cell
              }
        }
    }