How to override form data source field lookup method.

 /// <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();

    }

}