How to adding Find or Filter functionality on Display method from AX Form

// VAR Changed on 24 四月 2012 at 10:41:52 by Jimmy Xie
static void THK_FilterOrFindOnFormMethod(Args _args)
{
/*
Adding Find\Filter functionality on Display method
Override Context method of Form control which is using display method and provide code for filter.
E.g I have done below for PhysicalInvent field of InventOnHandItem form.
*/
    void context()
    {
        int                     selectedMenu;
        real                    test;
        formrun                 fr;
        Args                    ag;
        Itemname                strtext;
        query                   q;
        queryrun                qr;
        queryBuildDataSource    qbds;
        PopupMenu               menu;// = new PopupMenu(element.hWnd());
        int a = menu.insertItem('Find');
        int b = menu.insertItem('Filter');
        int c = menu.insertItem('Remove Filter');

        selectedMenu = menu.draw();
        switch (selectedMenu)
        {
            case -1:
                break;
            case a:
                ag = new args("SysformSearch");
                fr = new formrun(ag);
                fr.run();
                fr.wait();
                strtext = fr.design().controlName('FindEdit').valueStr();
                if(strtext)
                {
                    q       = inventSum_Ds.query();
                    qbds    = q.dataSourceTable(tablenum(InventSum));
                    qbds.addRange(FieldNum(InventSum,PhysicalInvent)).value(SySQuery::value(strtext));
                    inventSum_Ds.query(Q);
                    inventSum_Ds.executeQuery();
                }
                break;
            case b:
                InventSum_DS.filter(FieldNum(InventSum,PhysicalInvent),Sysquery::value(InventSum.PhysicalInvent()));
                break;
            case c :
                InventSum_DS.removeFilter();
                break;
            Default:
                break;
        }
    }
}