In the user control code behing add an event handler to the CreatingDataSetRun event on the AxDataSource control protected void Page_Init(object sender, EventArgs e) { this.AxDataSource1.CreatingDataSetRun += new EventHandler (AxDataSource1_CreatingDataSetRun); } Set the param value to the event arugments void AxDataSource1_CreatingDataSetRun(object sender, CreatingDataSetRunEventArgs e) { e.DataSetRunArgs.parm = "4000"; } In AOT override or add method in the data set and use element.args().parm() to received the paramter public void executeQuery() { QueryBuildRange custRange; ; custRange = SysQuery::findOrCreateRange(this.query().dataSourceNo(1), fieldnum(CustTable, AccountNum)); custRange.value(element.args().parm()); super(); } You can also pass an Enum. For example void AxDataSource1_CreatingDataSetRun(object sender, CreatingDataSetRunEventArgs e) { e.DataSetRunArgs.parmEnumType = EnumMetadata.EnumNum(this.AxSession, "EPFo...