How to Create Multiselection Lookup in D365FO

In this blog post, we will walk through the steps to create a multiselection lookup in Dynamics 365 for Finance and Operations (D365FO). We will use a sample code to demonstrate the process. Also, you can refer to the standard class 'ENGIEMultiSelectionLookupUIBuilder'.

Step 1: Create the Data Contract Class

First, we need to create a data contract class. This class will hold the list of project IDs that we want to select.

internal final class DemoMultiSelectionLookupContract implements SysOperationValidatable, SysOperationInitializable
{
    private List projIdList;

    [DataMemberAttribute("ProjectId"), 
    AifCollectionTypeAttribute("ProjectId", Types::String),
    SysOperationLabelAttribute(literalStr("@SYS103748")),
    SysOperationDisplayOrderAttribute('7')]
    public List parmProjIdList(List _listProjId = projIdList)
    {
        projIdList = _listProjId;
        return projIdList;
    }
    
    public void initialize()
    {

    }
}
    

Step 2: Create the UI Builder Class

Next, we create a UI builder class to add the dialog field for the project ID selection.

public final class DemoMultiSelectionLookupUIBuilder extends SysOperationAutomaticUIBuilder
{
    protected DialogField addDialogField(IdentifierName _methodName, Object _dataContract = this.dataContractObject())
    {
        DialogField dialogField;

        switch (_methodName)
        {
            case methodStr(DemoMultiSelectionLookupContract, parmProjIdList):
                projIdField = this.dialog().addField(extendedTypeStr(ProjId), "@SYS103748", "Select project id those invoice want to export");
                dialogField = projIdField;
                break;

            default:
                dialogField = super(_methodName, _dataContract);
                break;
        }

        return dialogField;
    }

    public void postRun()
    {
        DemoMultiSelectionLookupContract dataContract = this.dataContractObject() as DemoMultiSelectionLookupContract;
        container selectFieldSources = this.selectField();
        super();

        ctrlProjId = SysLookupMultiSelectCtrl::constructWithQueryRun(
            this.dialog().formRun(),
            projIdField.control(),
            new QueryRun(queryStr(ProjTable)),
            true,
            selectFieldSources);
    }

    public container selectField()
    {
        return [tableNum(ProjTable), fieldNum(ProjTable, ProjId)];
    }

   
}
    

Step 3: Create the Service Class

Finally, we create a service class to handle the business logic for the multiselection lookup.

internal final class DemoMultiSelectionLookupService extends SysOperationServiceBase
{
    System.Exception ex;
    internal void runExport(DemoMultiSelectionLookupContract _exportAttachmentsContract)
    {
        try
        {
            List projectList = _exportAttachmentsContract.parmProjIdList();
        }
        catch (ex)
        {
            this.logException(ex);
        }
    }
}
    

Step 4: Create the Controller Class

Finally, we create a controller class to call the service class.

public class DemoMultiSelectionLookupController extends SysOperationServiceController implements BatchRetryable
{
    public static void main(Args _args)
    {
        DemoMultiSelectionLookupController controller = DemoMultiSelectionLookupController::construct();
        controller.parmDialogCaption("@ApplicationFoundation:ExportAttachments");
        
        controller.startOperation();
    }

    public static DemoMultiSelectionLookupController construct(SysOperationExecutionMode _executionMode = SysOperationExecutionMode::Synchronous)
    {
        return new DemoMultiSelectionLookupController(
            classStr(DemoMultiSelectionLookupService),
            methodStr(DemoMultiSelectionLookupService, runExport),
            _executionMode);
    }

    [Hookable(false)]
    public final boolean isRetryable()
    {
        return false;
    }
}
    

And that's it! You now have a multiselection lookup in D365FO. This example demonstrates how to create a data contract, UI builder, service class, and controller class to achieve this functionality.