linking two .h file

[zole_ria9]

How would you call a label (or panel, or etc) and then change its properties from another .h file?

Here's my code (snippet):
Form1.h

//let's assume that panel3 is already declared and there are no problem with it
#include "LinesDraw.h";
public ref class Form1 : public System::Windows::Forms::Form	{
	public: System::Windows::Forms::Label^  sample;
	void InitializeComponent(void){
		this->sample = (gcnew System::Windows::Forms::Label());
		this->panel3->Controls->Add(this->sample);
	}
}

LinesDraw.h

#include "Form1.h"
public class LinesDraw{
public: 
	//constructors and destructors here
	void hello(){ 
		Form1 f; 
		//here I tried putting f.sample; but it isn't working
		//any idea on how I will call sample?
		//and also how would I change its Text Property?
		//is something like this ok? 
		//f.sample ->Text = L"Sample"
	}
};

I want to call sample since I want to change its properties.
For example changing its Text property.
And also. this is just for curiosity but why is there an L in changing/declaring Text and Name property before the name itself?

Also, Form1.h is a managed form while LinesDraw.h is an unmanaged.
I wonder if its ok?? And if it is, how would I call a managed class using unmanaged class?

Any help would be appreciated.