Question

I have the following code and Visual Studio C++ reports two errors:

#include "windows.h"

#using <mscorlib.dll>

#using <System.dll>

#using <System.Windows.Forms.dll>

using namespace System::Windows::Forms;

__gc class MyForm : public Form

{

public: 

MyForm()

 { 

     Text = "Hello, Windows Forms!";

     Button* button = new Button();

     button->Text = "Click Me!";

     button->Click += new EventHandler(this, button_click);

     this->Controls->Add(button);

}

void button_click(Object* sender, EventArgs* e)

{

MessageBox::Show("Ouch!");

}

};

int CALLBACK WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)

{

Application::Run(new MyForm);

}

and the errors:
error C2061 Syntax Error: Event Args
error C2061 Syntax Error: EventHandler

What should I do to get the code running ?
Thanx in advance.

Answer 1

Add line ‘using namespace System;’

    using namespace System;

Change ref to button_click as: &MyForm::button_click

Full working code:

    #include "windows.h" 

    #using <mscorlib.dll> 
    #using <System.dll> 
    #using <System.Windows.Forms.dll> 

    using namespace System::Windows::Forms; 
    using namespace System;

    __gc class MyForm : public Form 
    { 

        public: 

        MyForm() 
        {  

             Text = "Hello, Windows Forms!"; 

             Button* button = new Button();  
             button->Text = "Click Me!"; 

             button->Click += new EventHandler(this, &MyForm::button_click); 

             this->Controls->Add(button);  
        } 

        void button_click(Object* sender, EventArgs* e) 
        { 
            MessageBox::Show("Ouch!"); 
        } 

    }; 

    int CALLBACK WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)  
    { 
      Application::Run(new MyForm);  
    }