How to declare and use global variables in C++ Windows Forms?

I am trying to use global variables in the default Form.h file in C++ windows form. I have two functions in Form.h file:

private: System::Void Button1_Click(System::Object^ sender, System::EventArgs^ e) {

//Some Code

}

and

private: System::Void Button2_Click(System::Object^ sender, System::EventArgs^ e) {

//Some Code

}

I want to declare globals variables in such a way that both of those above functions can access and modify the variables.

I have already tried making a separate Globals.h file where I have the following code:

namespace Globals { extern bool globalVariable1 = false;

}

In my Form.h file, I have an "#include "Globals.h" declaration. And then I am accessing the global variables in Globals.h and modifying as

Globals::globalVariable1 = true;

This doesn't seem to work.