Updating a parent form from a subform

Subforms do not know about their parent form and there is no way to pass a reference of the parent form to a subform to "link" the two. Instead we have to go an unconventional route which is described in this recipe.

How to do it...

1. Create a new form using the Object Designer.

2. Add the following global variables:

   Name	Type	Subtype
   A	Integer
   B	Integer
   XMLDoc	Automation	'Microsoft XML, v6.0'.DOMDocument60

3. Add a global function named SendMessage with the following code:

   XMLDoc.loadXML('<root></root>');
   

4. Add a global function named GetA that returns an integer with the following code:

   EXIT(A);
   

5. Add a global function named GetB that returns an integer with the following code:

   EXIT(B);
   

6. Add a global function named SetXMLDoc that takes in the following parameter:

   Name	Type	Subtype
   XMLDocParam	Automation	'Microsoft XML, v6.0'.DOMDocument60

7. Add the following code to the function:

   XMLDoc := XMLDocParam;
   

8. Add two textboxes to the form.

9. Set the SourceExpr...