Question

Is it possible to add the “DeleteOnNull=true” on a custom class instead of modifying the DBML (generated) class directly?

For example, let’s say this is a part of my generated dbml class:

[Table(Name="OrderDetails")]
public partial class OrderDetail : 
       INotifyPropertyChanging, INotifyPropertyChanged
{
    // deleted for brevity

    [Association(Name="Order_OrderDetail", 
         Storage="_Order", ThisKey="OrderId", 
         OtherKey="OrderId", IsForeignKey=true, DeleteOnNull=true)]
    public Order Order 
    {
        get { /* deleted */ }
        set { /* deleted */ }
    }
}

So is it possible to put the “DeleteOnNull=true” on a separate class? Is it is? How? I have tried the following without any luck:

[MetadataType(typeof(OrderDetailMetadata))]
public partial class OrderDetail {
    internal sealed class OrderDetailMetadata
    {
        [Association(DeleteOnNull = true)]
        public object Order;
    }
}

Answer 1

Better late than never:

If you have been using the Designer to create your LTS config and entities, you can right-click on the DBML file, and choose “Open With…”. Now select XML Editor and click OK.

Find your Order_OrderDetail association in this file, then add DeleteOnNull="true" to it. Save the file and let LTS re-generate your classes for you. Done! No more having your changes to the generated code file overwritten again!