D365FOE. How to override form data source field lookup method.

A long time ago, I wrote a blog post explaining how to override form data source field methods. I skipped lookup, most popular method, because it did not work and logged a bug with MS hoping that it would be fixed soon. It took more time than I expected, but finally, it works!

Here is a small example how to override it. I’m going to use approach similar to previous post, full example is available on GitHub. Version I’m using is 7.3 PU13.

/// <summary>
/// Handles events raised by <c>SalesTable</c> form.
/// </summary>
public class SalesTableEventHandler
    /// <summary>
    /// Post event handler for <c>SalesTable</c> <c>SalesLine</c> Initialized event.
    /// </summary>
    /// <param name=“_sender”></param>
    /// <param name=“_e”></param>
    [FormDataSourceEventHandler(formDataSourceStr(SalesTable, SalesLine), FormDataSourceEventType::Initialized)]
    public static void SalesLine_OnInitialized(FormDataSource _sender, FormDataSourceEventArgs _e)
        var overrides = SalesTableFormExtensionOverrides::construct();

        _sender.object(fieldNum(SalesLine, ItemId)).registerOverrideMethod(methodStr(FormDataObject, lookup),
            methodStr(SalesTableFormExtensionOverrides, ItemId_OnLookup), overrides);

/// <summary>
/// Contains methods which are used to override <c>SalesLine</c> data source field methods.
/// </summary>
public class SalesTableFormExtensionOverrides
    protected void new()

    /// <summary>
    /// Constructs a new instance of <c>SalesTableFormExtensionOverrides</c> class.
    /// </summary>
    /// <returns>
    /// A <c>SalesTableFormExtensionOverrides</c> class.
    /// </returns>
    public static SalesTableFormExtensionOverrides construct()
        return new SalesTableFormExtensionOverrides();

    /// <summary>
    /// Provides a lookup for the <c>InventTable</c> table
    /// </summary>
    /// <param name = "_callingControl">
    /// The form string control object with which to perform the lookup.
    /// </param>
    public void ItemId_OnLookup(FormStringControl _callingControl)
        SysTableLookup sysTableLookup = SysTableLookup::newParameters(tableNum(InventTable), _callingControl);

        sysTableLookup.addLookupfield(fieldNum(InventTable, ItemId));
        sysTableLookup.addLookupfield(fieldNum(InventTable, NameAlias));


As you may notice, signature of this method is different to signature of other methods, like validate or jumpRef. They accept FormDataObject as a parameter and lookup() accepts FormStringControl. It looks a bit inconsistent for me and we need to be extra careful here because you can register override method with any signature and get error in the run-time.

8 thoughts on “D365FOE. How to override form data source field lookup method.

  1. Shashi Sadasivan February 22, 2018 / 1:06 am

    Thanks for the write up ievgen. Do you think this is valid for PU13 or 7.3 ?
    im with PU11 and 7.2 and this doesnt work. i get a invalid exception in the Output window, but no details for it. So im onto using the event handler on the form control instead for now

    • Ievgen Miroshnikov February 22, 2018 / 1:11 am

      It’s definitely PU, not application release, If I were you I would update to PU12 and try.

  2. Mantas Sliogeris July 6, 2018 / 8:35 am

    Hi, Ievgen, thanks for this tutorial!
    I have tried to override data source field visible method to no avail. Have you tried to override visible method?
    I wonder, maybe it is the same case as it was with lookup method – it is not implemented by microsoft yet.

    • Ievgen Miroshnikov July 6, 2018 / 9:41 am

      Hi Mantas Sliogeris, I have not tried but you need to double check that you have correct method signature, because if it is incorrect AX just ignores it without any error. Second step would be to log a bug and make MS fix it as I did with lookup.

  3. Tobias Brue March 15, 2019 / 8:19 am

    Do you know if this will still work with v10 and PU25?
    Becaus in PU25 the following feature is deprecated and will be turned off in a further PU:
    Overriding internal methods is deprecated

    For me it looks like this will stop Code which is using registerOverrideMethod() from working in the future. I think most of the behaviour can be handled by using CoC but i’m not 100% sure.

      • Tobias Brue March 18, 2019 / 8:17 am

        Good to know, thanks for the testing.

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