请问一下，win32应用程序中的instance参数和创建的窗口之中的参数instance有什么联系

Question

#include<windows.h>

LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);

HINSTANCE hInstance;

class CWndFrame

{

public:

void RegisterClass()

{

WNDCLASS wc;

wc.cbClsExtra=0;

wc.cbWndExtra=0;

wc.hbrBackground=(HBRUSH)GetStockObject(BLACK_BRUSH);

wc.hCursor=LoadCursor(NULL,IDC_ARROW);

wc.hIcon=LoadIcon(NULL,IDI_APPLICATION);

wc.hInstance=hInstance;//

wc.lpfnWndProc=WndProc;//

wc.lpszClassName="liyanfei";

wc.lpszMenuName=NULL;

wc.style=CS_VREDRAW|CS_HREDRAW;

::RegisterClass(&wc);

}

void CreateWindow1()

{

m_hWnd=::CreateWindow("liyanfei","李艳飞",WS_OVERLAPPED,20,10,500,400,NULL,NULL,hInstance,NULL);

}

void UpdateWindow()

{

::UpdateWindow(m_hWnd);

}

void ShowWindow()

{

::ShowWindow(m_hWnd,SW_SHOW);

}

private:

HWND m_hWnd;

};

class CWndApp

{

public:

void InitInstance()

{

CWndFrame *p=new CWndFrame;

p->RegisterClass();

p->CreateWindow1();

p->ShowWindow();

p->UpdateWindow();

delete p;

}

void Run()

{

MSG msg;

while(GetMessage(&msg,NULL,0,0))

{

TranslateMessage(&msg);

DispatchMessage(&msg);

}

}

//private:

// CWndFrame *p;

};

int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine,int nShowCmd)

{

CWndApp theApp;

theApp.InitInstance();

theApp.Run();

return 0;

}

LRESULT CALLBACK WndProc(HWND hWnd,UINT message,WPARAM wParam,LPARAM lParam)

{

switch(message)

{

case WM_LBUTTONDOWN:

MessageBox(hWnd,"nihao","liyanfei",0);

break;

case WM_DESTROY:

PostQuitMessage(0);

break;

default:

return DefWindowProc(hWnd,message,wParam,lParam);

}

return 0;

}