how to write my own Exception.Message of DataError event according to the control of cellvalidating

hi

   i'd like to ask, in DataError event ,i want to write my own message. For example,in cellvalidating I want write some of my own message, and in  DataError i can display them with a messgaebox

   Or, i want to say "in cellvalidating event, I can"throw" some special exception for DataError Event".I dont know whether I should throw a new exception or not. as we know, for DataError event they provide some type of DataGridViewDataErrorEventArgs.Exception.Message, I just would like that,in cellvalidating event,I can "cutomize" the DataGridViewDataErrorEventArgs.Exception.Message

  i'd like to explain one thing, for example, for dataError event it has it's errormessage,for example, when there is a string value for int column, but my validating event will have a control to make messgaebox.show,too,with my own message. in this case, in runtime the users will has 2 messagebox at one time.thats not good. but i still need DataError event to catch some errores.

some thing like

  
privatevoid dataGridView1_CellValidating(object sender, DataGridViewCellValidatingEventArgs e)        {            if (e.FormattedValue.ToString() == "aa")            {                //wrtie a special frase such as "you can not input aa according to the regular"            }
         }
 private void dataGridView1_DataError(object sender, DataGridViewDataErrorEventArgs e)        {           //MessageBox.show "you can not input aa according to the regular"             e.Cancel = true;         }