How to create multi-select lookup dialog for class in AX 2012

Create these methods in your class:

class DICPromotion2SalesLine extends Runbase

{

    

    DialogRunbase               dialog;

    DialogGroup                 dialogGrp;

    

    FormBuildStringControl      fbsCtrlPromotion;

    FormStringControl           fsCtrlPromotion;

    container                   returnPromotion;

    SysLookupMultiSelectCtrl    msCtrlPromotion;

    str                         promotionRange;

}

protected Object dialog()

{

    FormBuildControl    setupGroupControl;

    ;

    dialog = super();

    dialog.alwaysOnTop(true);

    dialog.windowType(FormWindowType::Standard);

    dialogGrp = dialog.addGroup('Promotion');

    setupGroupControl = dialog.formBuildDesign().control(dialogGrp.formBuildGroup().id());

    fbsCtrlPromotion = setupGroupControl.addControl(FormControlType::String, identifierstr(DICPromotionID));

    fbsCtrlPromotion.label('Promotion id');

    dialog.allowUpdateOnSelectCtrl(true);

    this.dialogSelectCtrl();

    return dialog;

}

public void dialogPostRun(DialogRunbase _dialog)

{

    FormRun formRun;

    super(dialog);

    formRun = _dialog.dialogForm().formRun();

    if (formRun)

    {

        fsCtrlPromotion = formRun.design().control(fbsCtrlPromotion.id());

/// you can build with your own query, or created query in system by method construct

        msCtrlPromotion = SysLookupMultiSelectCtrl::constructWithQuery(formRun, fsCtrlPromotion, this.buildQuery());

    }

}

// build your Query here

public query buildQuery()

{

    Query                   q          = new Query();

    QueryBuildDataSource    qbds;

    DICTmpPromotionTable    tmpPromotionTable;

    ;  

    qbds    = q.addDataSource(tablenum(DICPromotionMaster));

    qbds.addSelectionField(fieldNum(DICPromotionMaster, PromotionID));

    qbds.addSelectionField(fieldNum(DICPromotionMaster, Description));

    qbds.addSelectionField(fieldNum(DICPromotionMaster, WithGroupItem));

    qbds.addSelectionField(fieldNum(DICPromotionMaster, Fromdate));

    qbds.addSelectionField(fieldNum(DICPromotionMaster, ToDate));   

        

    tmpPromotionTable = this.searchPromotion();

    while select tmpPromotionTable

    {

        qbds.addRange(fieldNum(DICPromotionMaster,PromotionID)).value(tmpPromotionTable.PromotionID);        

    }

    return q;

}

public boolean getFromDialog()

{

    boolean         ret;

    #Characters

    

    ret = super();

   

    if (msCtrlPromotion)

    {

        returnPromotion = msCtrlPromotion.getSelectedFieldValues();        

    }

    promotionRange    = con2StrUnlimited(returnPromotion,#comma);

   

    return ret;

}