private void dgvInfoPerson_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
        {
            if (dgvInfoPerson.CurrentCellAddress.X == dgvInfoPerson.Columns["colCboDeptNo"].Index)
            {
                cbo = e.Control as ComboBox;
                if (cbo != null)
                {
                    cbo.DropDownStyle = ComboBoxStyle.DropDown;
                    cbo.AutoCompleteMode = AutoCompleteMode.SuggestAppend;
                }
            }
        }

        private void dgvInfoPerson_CellValidating(object sender, DataGridViewCellValidatingEventArgs e)
        {
            if (dgvInfoPerson.CurrentCellAddress.X == dgvInfoPerson.Columns["colCboDeptNo"].Index)
            {
                //问题出在这里.如果你输入的是ValueMember的值的话就没问题.但你如果输入的是DisplayMember的值的话就不会选中.
                //如ValueMember="MAN" DisplayMember="管理部",如果你在此单元格输入MAN就没问题,但输入管理部就不会选中.但用户就应该是输入管理部
                  //而不是输入MAN.
                dgvInfoPerson.Rows[e.RowIndex].Cells[e.ColumnIndex].Value = e.FormattedValue;
            }
        }

            //判断键盘按下的键。如果等于“enter”，则send一个“{tab}”。模拟按下“tab”键，实现单元格。向下移动
            if (keyData == Keys.Enter )
            {
                e.Handled = false;//加上这个试试。不行的话像下一句发送一个回车的按键消息
                System.Windows.Forms.SendKeys.Send("{tab}");
                return true;
            }

------解决方案--------------------

public void ProcessHotkey(Message m) //按下设定的键时调用该函数
       {
           try
           {
               IntPtr id = m.WParam; //IntPtr用于表示指针或句柄的平台特定类型
               //MessageBox.Show(id.ToString());
               string sid = id.ToString();
               switch (sid)
               {
                   case "100":
                       additem.ShowDialog();
                       if (additem.DialogResult == DialogResult.OK)
                       {
                           dgItemSellList[4, dgItemSellList.CurrentCell.RowIndex].Value = additem.txtnum.Text.ToString();
                       }
                       break;
                   case "200":
                       if(MessageBox.Show("确定要关闭此窗体吗？","关闭提示",MessageBoxButtons.YesNo)==DialogResult.Yes)
                       this.Close();
                       break;
                   case "300":
                       fullpay = txttotal.Text;
                       billcode = txtbillcode.Text;
                       date = txtdate.Text;
                       handle = comhandle.Text;
                       cust = comcust.Text;
                       memo = txtMemo.Text;
                       SellDetail.SellPayment sell = new SellMain.SellDetail.SellPayment();
                       if (newitemtable.Rows.Count != 0)
                       {
                           sell.ShowDialog();
                       }
                       if (sell.DialogResult == DialogResult.OK)
                       {
                           txtsfull.Text = sell.txtfullpay.Text;
                           txtspay.Text = sell.txtpay.Text;
                           txtschange.Text = sell.txtchange.Text;
                           txttotal.Text = "";
                           txtallnum.Text = "";
                           newitemtable.Clea