给datagridview的下拉框添加valueChange事件

修改datagridview的EditMode属性为EdutOnEnter，否则需要点2次以上才出现下拉框

1.给DataGridView添加EditingControlShowing事件；

2.编辑EditingControlShowing事件：

public void dgv_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
  DataGridView dgv = sender as DataGridView;

    //判断相应的列
    if (dgv.CurrentCell.GetType().Name == "DataGridViewComboBoxCell" && dgv.CurrentCell.RowIndex != -)
     {
      //添加下拉事件
      (e.Control as ComboBox).SelectedIndexChanged += new EventHandler(ComboBox_SelectedIndexChanged);
     }
}

3.定义下拉事件

   public void ComboBox_SelectedIndexChanged(object sender, EventArgs e)
        {
                ComboBox combox=sender as ComboBox;

                 //去掉事件，避免一直触发
                 combox.Leave+=new EventHandler(combox_Leave);

                 if (combox.SelectedItem != null)
                 {
                     //添加你需要处理的代码
                 }
        }

4.添加删除事件

   public void combox_Leave(object sender, EventArgs e)
   {
            ComboBox combox = sender as ComboBox;
            //做完处理撤销动态事件
            combox.SelectedIndexChanged -= new EventHandler(ComboBox_SelectedIndexChanged);
   }

来自 https://blog.****.net/a312100321/article/details/25195311