前言

在Form的字段的onLookUp方法中，添加下拉框。

一、复制onLookUp事件方法

二、LookUp方法

[FormControlEventHandler(formControlStr(EcoResProductDetailsExtended, VyaKeyItemType_VyaMaterialSubCode), FormControlEventType::Lookup)]
    public static void VyaKeyItemType_VyaMaterialSubCode_OnLookup(FormControl sender, FormControlEventArgs e)
    {
        FormControlCancelableSuperEventArgs ce  = e as FormControlCancelableSuperEventArgs;
        FormRun formRun =  sender.formRun();
        FormStringControl vyaMaterialCodeCtrl = formRun.design().controlName(formControlStr(EcoResProductDetailsExtended, VyaKeyItemType_VyaMaterialCode));
        str vyaMaterialCodeStr = vyaMaterialCodeCtrl.text();
        Query                   query           = new Query();
        QueryBuildDataSource    qbds;
        QueryBuildRange         qbr;
        SysTableLookup          sysTableLookup  = SysTableLookup::newParameters(tableNum(VyaMaterialsSubCategories), sender);

        sysTableLookup.addLookupfield(fieldNum(VyaMaterialsSubCategories, VyaCode));
        sysTableLookup.addLookupfield(fieldNum(VyaMaterialsSubCategories, VyaDescription));

        qbds = query.addDatasource(tablenum(VyaMaterialsSubCategories));
        qbr = qbds.addRange(fieldNum(VyaMaterialsSubCategories,VyaParentMaterial));
        qbr.value(queryValue(vyaMaterialCodeStr));

        sysTableLookup.parmQuery(query);
        sysTableLookup.performFormLookup();

        ce.CancelSuperCall();
    }