DataGridView下拉框事件……问题

Question

DataGridView单元格改成下拉框,然后有加减
运行选中加，那么一个字段中的数据如果是正数:5000,就变成-5000
.请问怎么实现啊.
下拉框的事件一直不明白在哪里

Answer 1

private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
  ComboBox combo = e.Control as ComboBox;
  if (combo != null)
  {
  combo.SelectedIndexChanged +=
  new EventHandler(ComboBox_SelectedIndexChanged);
  }
}private void ComboBox_SelectedIndexChanged(object sender, EventArgs e)
{
  ComboBox cb=(ComboBox)sender;
  //这里获取到ComboBox对象后，判断对象的
  if(cb.SelectedItem.toString()=="+")
    ....
}

Answer 2

private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
  {
  if (this.dataGridView1.CurrentCell.OwningColumn.Name == "clmTest")
  {
  ((ComboBox)e.Control).SelectedIndexChanged += new EventHandler(ComboBox_SelectedIndexChanged);
  }  }private void ComboBox_SelectedIndexChanged(object sender, EventArgs e)
  {
  this.dataGridView1.CurrentRow.Cells["name"].Value = ((ComboBox)sender).Text;
  }