Update parent window from child?

I have a window that displays product information. You can edit the info by clicking the edit button and a new form pops up where all the fields can be changed in various ways. When you are done you can click Save or Cancel. What I am trying to do is when the user clicks 'Save' and the product is changed, get the parent window to automatically display the updated information. I tried doing the following [pseudo-code]:

parent window Edit button:

Code:

private: System::Void bEdit_Click(System::Object^  sender, System::EventArgs^  e) {
   properties_form ^pf = gcnew properties_form;

   //set the fields in pf to the correct values, based on values from fields in this form
   pf->MdiParent = this;
   pf->show();
}

child window save button:

Code:

private: System::Void bSave_Click(System::Object^  sender, System::EventArgs^  e){

        //get the new info from the editable fields
        //make a new product to hold the info
        //replace the old product with the modified one in the DB
	
         ParentForm->Refresh();

	Close();
			 
}

this code compiled but gave me an error saying the parent form is not an mdi container. I don't even know what an MdiContainer is but I just trying to work with what I could find on MSDN before asking silly questions here. Now I'm stuck and here I am... thanks

I know nothing of C# (or at least that looks like it, or perhaps managed C++..) but I can tell you MDI is Multiple Document Interface.