Calling a form from another form

Managed C++ does not let you call a form by its form name. In C# you can do formname.function if it is a public function. You can call a perform click in C# just by the formname. In managed c++ it is a little different.

I had to write a callback function that sends messages just to call a previous form. Here is the code:

At the header I inserted:


//#include <windows.h>    // You could theoretically include Windows.h to get

                                     // all of the WM_ message values, but then your

                                     // basic .NET objects like MessageBox would no longer

                                     // function without a series of #ifndefs.


// Define WM_USER using the value in windows.h

#define WM_USER 0x0400

#define WM_PLAY 0x0401

#define WM_STOP 0x0402

#define WM_RESTART 0x0403

#define WM_PAUSE 0x0404

#define WM_EXITME 0x0405


// Define our custom message

#define MSG_CHILDTEXT (WM_USER+1) // Nothing

#define MSG_CHILDPLAY (WM_PLAY+1)

#define MSG_CHILDSTOP (WM_STOP+1)

#define MSG_CHILDRESTART (WM_RESTART+1)

#define MSG_CHILDPAUSE (WM_PAUSE+1)

#define MSG_CHILDEXIT (WM_EXITME+1)

Declare this in the new form (child form)


public: System::Windows::Forms::NativeWindow^ m_nwndParent;

Assign a handle in the parent form


//myFullTrans->StartClick = ionTimer::Form1::childForm_StartClick();

			 myFullTrans->m_nwndParent = gcnew System::Windows::Forms::NativeWindow ();

			 myFullTrans->m_nwndParent->AssignHandle (this->Handle);

Create a functino in the new form


private: System::Void msgToParentForm(int m)

		 {

			 				// Create a new windows message object

			   System::Windows::Forms::Message msgTextSetter;


			   // Set the message type to our custom message

			   msgTextSetter.Msg = m;


			   // Tell the NativeWindow object to send the message

			   // to the default WndProc of the window whose handle

			   // it represents

			   m_nwndParent->DefWndProc (msgTextSetter);

		 }

Call the function


msgToParentForm(MSG_CHILDPAUSE);

//////////////////////////////////////////////////////////// // Override to get messages from child ////////////////////////////////////////////////////////// public: virtual System::Void WndProc(System::Windows::Forms::Message % message) override { try { switch (message.Msg) { // Handle our incoming custom message case MSG_CHILDTEXT: { // This custom message should set the text of the parent's // main textbox break; } // Start the Timer - Run case MSG_CHILDPLAY: { toolStripButton1_Click(nullptr,nullptr); break; } case MSG_CHILDSTOP: { stopBtn_Click(nullptr,nullptr); break; } case MSG_CHILDRESTART: { restartBtn_Click(nullptr,nullptr); break; } case MSG_CHILDPAUSE: { pauseBtn_Click(nullptr,nullptr); break; } case MSG_CHILDEXIT: { myFullTrans->Close(); this->Close(); break; } // All other messages should be sent to the default WndProc // for System::Windows::Forms default: { Form::WndProc (message); break; } } // End Case } catch (System::Exception^) { MessageBox::Show("Error"); } }