c# - SqlDependency Slow performance -

i use query notification of sqldependency , here's scenario:

i have small table 100 records quite large data inside these records

here's code:

private void autoupdate() {     sqldependency.stop(connectionstring);     sqldependency.start(connectionstring);      using (sqlconnection cn = new sqlconnection(connectionstring))     {         using (sqlcommand cmd = cn.createcommand())         {             cmd.commandtype = commandtype.text;             cmd.commandtext = @"select [number], [creation date],[createdby], [approved]   [dbo].[mytable] order number";              dt = new datatable();             cmd.notification = null;              sqldependency dep = new sqldependency(cmd);              dep.onchange += new onchangeeventhandler(dep_onchange);              cn.open();               using (sqldatareader dr = cmd.executereader())             {                 dt.load(dr);             }              datagridview1.datasource = dt;         }     }  } 

and onchange event use following code

private void dep_onchange(object sender, sqlnotificationeventargs e) {      if (this.invokerequired)     {         datagridview1.begininvoke(new methodinvoker(autoupdate));      }     else     {          autoupdate();      }      sqldependency dep = sender sqldependency;     dep.onchange -= new onchangeeventhandler(dep_onchange); } 

i use cellvaluechanged event trigger if user changes value in datagridview

the problem is: when user changes value of 1 cell, updates database , fires onchange event cause reload datatable records

imagine user wants fill number field value '0' first 50 record

the user press down arrow key 0 on keyboard continuously, , cause huge amount of data sent , received, because application receive datatable database after every press, , while trying experienced slow performance

is there better approach implement query notification?

is there way make onchange event works on affected row? not whole table?