windows編程--建立視窗

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第一個win32程式，簡單的建立視窗：

#include <windows.h> LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,                    PSTR szCmdLine, int iCmdShow){     static TCHAR szAppName[] = TEXT ("HelloWin") ;     HWND         hwnd ;     MSG          msg ;     WNDCLASS     wndclass ;     wndclass.style         = CS_HREDRAW | CS_VREDRAW ;     wndclass.lpfnWndProc   = WndProc ;     wndclass.cbClsExtra    = 0 ;     wndclass.cbWndExtra    = 0 ;     wndclass.hInstance     = hInstance ;     wndclass.hIcon         = LoadIcon (NULL, IDI_APPLICATION) ;     wndclass.hCursor       = LoadCursor (NULL, IDC_ARROW) ;     wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;     wndclass.lpszMenuName  = NULL ;     wndclass.lpszClassName = szAppName ;     if (!RegisterClass (&wndclass))     {          MessageBox (NULL, TEXT ("This program requires Windows NT!"),                       szAppName, MB_ICONERROR) ;          return 0 ;     }          hwnd = CreateWindow (szAppName,                  // window class name                          TEXT ("The Hello Program"), // window caption                          WS_OVERLAPPEDWINDOW,        // window style                          CW_USEDEFAULT,              // initial x position                          CW_USEDEFAULT,              // initial y position                          CW_USEDEFAULT,              // initial x size                          CW_USEDEFAULT,              // initial y size                          NULL,                       // parent window handle                          NULL,                       // window menu handle                          hInstance,                  // program instance handle                          NULL) ;                     // creation parameters          ShowWindow (hwnd, iCmdShow) ;     UpdateWindow (hwnd) ;          while (GetMessage (&msg, NULL, 0, 0))     {          TranslateMessage (&msg) ;          DispatchMessage (&msg) ;     }     return msg.wParam ;}LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam){     HDC         hdc ;     PAINTSTRUCT ps ;     RECT        rect ;          switch (message)     {     case WM_CREATE:return 0 ;               case WM_PAINT:          hdc = BeginPaint (hwnd, &ps) ;                    GetClientRect (hwnd, &rect) ;                    DrawText (hdc, TEXT ("Hello, Windows Program!"), -1, &rect,                    DT_SINGLELINE | DT_CENTER | DT_VCENTER) ;                    EndPaint (hwnd, &ps) ;          return 0 ;               case WM_DESTROY:          PostQuitMessage (0) ;          return 0 ;     }     return DefWindowProc (hwnd, message, wParam, lParam) ;}

視窗是由視窗類別建立的即WNDCLASS，視窗類別確定了處理視窗訊息的視窗過程。

MSDN中是這樣定義的：

typedef struct {  UINT      style;  WNDPROC   lpfnWndProc;  int       cbClsExtra;  int       cbWndExtra;  HINSTANCE hInstance;  HICON     hIcon;  HCURSOR   hCursor;  HBRUSH    hbrBackground;  LPCTSTR   lpszMenuName;  LPCTSTR   lpszClassName;} WNDCLASS, *PWNDCLASS;

在程式中，我們一般這樣定義和初始化

  WNDCLASS     wndclass ;     wndclass.style         = CS_HREDRAW | CS_VREDRAW ;     wndclass.lpfnWndProc   = WndProc ;     wndclass.cbClsExtra    = 0 ;     wndclass.cbWndExtra    = 0 ;     wndclass.hInstance     = hInstance ;     wndclass.hIcon         = LoadIcon (NULL, IDI_APPLICATION) ;     wndclass.hCursor       = LoadCursor (NULL, IDC_ARROW) ;     wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;     wndclass.lpszMenuName  = NULL ;     wndclass.lpszClassName = szAppName ;

wndclass.style欄位表示類的風格，具體參加MSDN：

Style	Action
CS_BYTEALIGNCLIENT	Aligns the window‘s client area on a byte boundary (in the x direction). This style affects the width of the window and its horizontal placement on the display.
CS_BYTEALIGNWINDOW	Aligns the window on a byte boundary (in the x direction). This style affects the width of the window and its horizontal placement on the display.
CS_CLASSDC	Allocates one device context to be shared by all windows in the class.
CS_DBLCLKS	Sends a double-click message to the window procedure when the user double-clicks the mouse while the cursor is within a window belonging to the class.
CS_DROPSHADOW	Windows XP: Enables the drop shadow effect on a window. The effect is turned on and off through SPI_SETDROPSHADOW.
CS_GLOBALCLASS	Specifies that the window class is an application global class. For more information, see Application Global Classes.
CS_HREDRAW	Redraws the entire window if a movement or size adjustment changes the width of the client area.
CS_NOCLOSE	Disables Close on the window menu.
CS_OWNDC	Allocates a unique device context for each window in the class.
CS_PARENTDC	Sets the clipping rectangle of the child window to that of the parent window so that the child can draw on the parent. A window with the CS_PARENTDC style bit receives a regular device context from the system‘s cache of device contexts.
CS_SAVEBITS	Saves, as a bitmap, the portion of the screen image obscured by a window of this class.
CS_VREDRAW	Redraws the entire window if a movement or size adjustment changes the height of the client area.

我們這裡選擇的是CS_HREDRAW | CS_VREDRAW，表示無論垂直還是水平尺寸的改變，視窗都將重繪。

wndclass.lpfnWndProc表示視窗過程設定，指向一個函數WndProc。

wndclass.cbClsExtra和cbWndExtra用於維護內部視窗結構中一些預留的空間，可以根據需要來使用這些預留的空間。

wndclass.hInstance表示應用程式的執行個體控制代碼即WinMain第一個參數。

wndclass.hIcon為該視窗類別設定表徵圖。若要使用本地的表徵圖，第一個參數必須為hInstance執行個體控制代碼，第二個參數為表徵圖標示，對於預定義的表徵圖以IDI開頭。

wndclass.hCursor與上面類似，載入滑鼠指標。

wndclass.hbrBackground指定背景色，這裡我們用白色畫刷。

wndclass.lpszMenuName即視窗菜單。

wndclass.lpszClassName為視窗類別指定名字。

這樣視窗類別的初始化完成，使用RegisterClass註冊類，下面就是視窗的建立了，

使用createWindow函數，MSDN定義如下：

HWND CreateWindow(  __in  LPCTSTR lpClassName,　　 //視窗名稱  __in  LPCTSTR lpWindowName,　　//視窗標題  __in  DWORD dwStyle,　　　　　　//視窗風格  __in  int x,　　　　　　　　　　 //x座標  __in  int y,　　　　　　　　　   //y座標  __in  int nWidth,　　　　　　   //長度  __in  int nHeight,　　　　　　　//高度　  __in  HWND hWndParent,　　　　 //父視窗控制代碼  __in  HMENU hMenu,            //視窗菜單控制代碼  __in  HINSTANCE hInstance,    //程式執行個體控制代碼  __in  LPVOID lpParam          //建立參數);

CreateWindow只是在內部建立視窗，即windows分配了一片記憶體，要想顯示視窗還要使用ShowWindow函數。

第一個參數是CreateWindow建立的視窗控制代碼，第二個是WinMain接受的iCmdShow值，該參數決定視窗初始顯示格式。

UpdateWindow是重繪視窗，這是通過發送一條WM_PAINT訊息完成的。

最後則是訊息的迴圈，即不斷接受訊息，當有訊息時調用WndProc函數進行處理。

 

windows編程--建立視窗