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));

        sysTableLookup.performFormLookup();
    }
}

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.