I have a Parent BO and a Child BO (using a Chikd Dialog) . I am at  the point where I want to save the Parent and the child out to the Database and want to check the rules first. So I have code like:

if (this.ParentBO1.CheckRules(true) && this.childBO1.CheckRules(true) )
{
this.childBo1.Save();
this.parentBO1.Save();
MessageBox.Show("Document has been saved", "Kernel Software",MessageBoxButtons.OK, MessageBoxIcon.Information);

}

All works fine. But I want to put validation code into the Parent Business object which will be dependent on what's in the child buisness object. e.g. Particular Customers (on the Parent Bo)  can only purchase certain Products (on the child BO). So at the stage I am validating the Parent BO, I need to loop through the Child BO .  I would like to put this valididation code into the CheckRulesOnCurrentRow on the parent BO but am not clear on how I will access the Child Business Object on the Parent Business Object. ( It cant really be done from the ChildBO because the Customer could be changed after a whole pile of products have been added ).

Not sure why I did it VB.NET...

DirectCast is a cast:

MyChildBO childBO = (MyChildBO)Me.ChildBusinessObjects[0];

Yes, ChildBusinessObjects is code only. It is a List<BusinessLayer> property. You don't set the children, just access them. This list is filled via the setting of the ParentBusinessObject on the children. Again, if you have just one child, then it'll be easy. If you have more than on child BO at a time, then you'd just need to check the type.

My ideas are just suggestions. There are many ways to get this done.  You'll figure out what works for you. I'm just trying to point out some things I've learned along the way that have really helped improve my code.

Hi Greg

I have that working very well now checking the Child Business Object from the Parent. Many thanks for all your help.

I will definitely revisit this when I have a bit more time , and have a look at a more purist approach as per your suggestions

Glad it helped and you have it working.  I'll be glad to continue the discussion and hear what you'll have learned by then regarding where to put validation/business rules.