override datagrid 的edit() 要怎么获得选定网格的值? protected override void Edit(CurrencyManager source, int rowNum, Rectangle bounds, bool readOnly, string instantText, bool cellIsVisible ) 
        {
            base.Edit(source, rowNum, bounds, readOnly, instantText, cellIsVisible);            string address = instantText;  //???一直取不到值
            ///?? string address=textbox.text.tostring();  取道空值???
            MessageBox.Show(address);
            string  exetion = Path.GetExtension(address);
            System.Diagnostics.Process proc = new System.Diagnostics.Process();
            if (exetion==".doc")
            {
                proc.StartInfo.FileName =@"winword.exe";
                proc.StartInfo.Arguments = address;
                try
                {
                    proc.Start();
                    proc.WaitForExit();
                }
                catch (System.Exception exp)
                {
                    string err = exp.Message;
                }   
            }
            if (exetion==".pdf")
            {
                proc.StartInfo.FileName = @"AcroRd.exe";
                proc.StartInfo.Arguments = address;
                try
                {
                    proc.Start();
                    proc.WaitForExit();
                }
                catch (System.Exception exp)
                {
                    string err = exp.Message;
                }   
            }
        }