How do I Automatically insert a new record into a child table when a new record is added to a parent table in Lightswitch?

Question

I have a Lightswitch Desktop Client application in C#. There is a parent table/entity called Participants and a child table called HouseIncomes. One of the field/properties in HouseIncomes is a string property called CurrentLevel with a choice list of Yes and No. When a new record is created in the Participants parent table, how can one record be added to the child HouseIncomes table with the default of "Yes" in the CurrentLevel field?

Answer 1

Using C#, this should work for your scenario:

Open up your Data Source, click in "Write Code" and select the Participants_Inserted option. (see image below) enter code similar to this: the naming conventions might be slightly out but I have guessed at what yours may be:

    partial void Participants_Inserted(Participants entity)
    {
        HouseIncome houseIncome = DataWorkspace.YOURDATASOURCE.HouseIncomes.AddNew();
        houseIncome.Participants = entity; //THIS ASSIGNS THE FOREIGN KEY RELATIONSHIP TO ITS PARENT
        houseIncome.CurrentLevel = "Yes"; //FOR STRING
        houseIncome.CurrentLevel = true; //FOR BOOLEAN
    }

This code is inserting your child data, linked to your parent data automatically, and setting the Current Level to your desired value.

Hope this helps...