Compiler Error #include

[Jennifer84]

I really wonder how it is possible to put text to a label from one Form to another.
So From Form8, I want to reach label23 on Form7.
I have tried out this below, but the compiler says:

'Form8' : undeclared identifier
'form8' : undeclared identifier
left of '->set' must point to class/struct/union/generic type
'->System::Windows::Forms::Form::Owner::set' : left operand has '' type,

Notice this: If I Only:

#include "Form7.h" in Form8, I will have the same compilererror, so the problem starts here.
Why is this happening ?

Form8:

#include "Form7.h"

//Inside namespace Form1 
private: Form7 ^myForm7;

myForm7->label23->Text = "Put Text In this label on this Form";