代码是写到datacolchanging事件,而不是datacolchanged事件
或者你改一下代码
If e.DataCol.Name = "订单号" Then Dim dr As DataRow dr = e.DataTable.Find("订单号 = '" & e.NewValue & "' and _Identify <> " & e.DataRow("_Identify")) If dr IsNot Nothing Then MessageBox.Show("此订单号已经存在!") e.Cancel = True End IfEnd If