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分享window 程序设计第五版中的问题
/*----------------------------------------
COLORS1.C -- Colors Using Scroll Bars
(c) Charles Petzold, 1998
----------------------------------------*/
#include <windows.h>
LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;
LRESULT CALLBACK ScrollProc (HWND, UINT, WPARAM, LPARAM) ;
int idFocus ;
WNDPROC OldScroll[3] ;
int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
PSTR szCmdLine, int iCmdShow)
{
static TCHAR szAppName[] = TEXT ("Colors1") ;
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 = CreateSolidBrush (0) ;
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, TEXT ("Color Scroll"),
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT,
CW_USEDEFAULT, CW_USEDEFAULT,
NULL, NULL, hInstance, NULL) ;
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)
{
static COLORREF crPrim[3] = { RGB (255, 0, 0), RGB (0, 255, 0),
RGB (0, 0, 255) } ;
static HBRUSH hBrush[3], hBrushStatic ;
static HWND hwndScroll[3], hwndLabel[3], hwndValue[3], hwndRect ;
static int color[3], cyChar ;
static RECT rcColor ;
static TCHAR * szColorLabel[] = { TEXT ("Red"), TEXT ("Green"),
TEXT ("Blue") } ;
HINSTANCE hInstance ;
int i, cxClient, cyClient ;
TCHAR szBuffer[10] ;
switch (message)
{
case WM_CREATE :
hInstance = (HINSTANCE) GetWindowLong (hwnd, GWL_HINSTANCE) ;
// Create the white-rectangle window against which the
// scroll bars will be positioned. The child window ID is 9.
hwndRect = CreateWindow (TEXT ("static"), NULL,
WS_CHILD | WS_VISIBLE | SS_WHITERECT,
0, 0, 0, 0,
hwnd, (HMENU) 9, hInstance, NULL) ;
for (i = 0 ; i < 3 ; i++)
{
// The three scroll bars have IDs 0, 1, and 2, with
// scroll bar ranges from 0 through 255.
hwndScroll[i] = CreateWindow (TEXT ("scrollbar"), NULL,
WS_CHILD | WS_VISIBLE |
WS_TABSTOP | SBS_VERT,
0, 0, 0, 0,
hwnd, (HMENU) i, hInstance, NULL) ;
SetScrollRange (hwndScroll[i], SB_CTL, 0, 255, FALSE) ;
SetScrollPos (hwndScroll[i], SB_CTL, 0, FALSE) ;
// The three color-name labels have IDs 3, 4, and 5,
// and text strings "Red", "Green", and "Blue".
hwndLabel [i] = CreateWindow (TEXT ("static"), szColorLabel[i],
WS_CHILD | WS_VISIBLE | SS_CENTER,
0, 0, 0, 0,
hwnd, (HMENU) (i + 3),
hInstance, NULL) ;
// The three color-value text fields have IDs 6, 7,
// and 8, and initial text strings of "0".
hwndValue [i] = CreateWindow (TEXT ("static"), TEXT ("0"),
WS_CHILD | WS_VISIBLE | SS_CENTER,
0, 0, 0, 0,
hwnd, (HMENU) (i + 6),
hInstance, NULL) ;
OldScroll[i] = (WNDPROC) SetWindowLong (hwndScroll[i],
GWL_WNDPROC, (LONG) ScrollProc) ;
hBrush[i] = CreateSolidBrush (crPrim[i]) ;
}
hBrushStatic = CreateSolidBrush (
GetSysColor (COLOR_BTNHIGHLIGHT)) ;
cyChar = HIWORD (GetDialogBaseUnits ()) ;
return 0 ;
case WM_SIZE :
cxClient = LOWORD (lParam) ;
cyClient = HIWORD (lParam) ;
SetRect (&rcColor, cxClient / 2, 0, cxClient, cyClient) ;
MoveWindow (hwndRect, 0, 0, cxClient / 2, cyClient, TRUE) ;
for (i = 0 ; i < 3 ; i++)
{
MoveWindow (hwndScroll[i],
(2 * i + 1) * cxClient / 14, 2 * cyChar,
cxClient / 14, cyClient - 4 * cyChar, TRUE) ;
MoveWindow (hwndLabel[i],
(4 * i + 1) * cxClient / 28, cyChar / 2,
cxClient / 7, cyChar, TRUE) ;
MoveWindow (hwndValue[i],
(4 * i + 1) * cxClient / 28,
cyClient - 3 * cyChar / 2,
cxClient / 7, cyChar, TRUE) ;
}
SetFocus (hwnd) ;
return 0 ;
case WM_SETFOCUS :
SetFocus (hwndScroll[idFocus]) ;
return 0 ;
case WM_VSCROLL :
i = GetWindowLong ((HWND) lParam, GWL_ID) ;
switch (LOWORD (wParam))
{
case SB_PAGEDOWN :
color[i] += 15 ;
// fall through
case SB_LINEDOWN :
color[i] = min (255, color[i] + 1) ;
break ;
case SB_PAGEUP :
color[i] -= 15 ;
// fall through
case SB_LINEUP :
color[i] = max (0, color[i] - 1) ;
break ;
case SB_TOP :
color[i] = 0 ;
break ;
case SB_BOTTOM :
color[i] = 255 ;
break ;
case SB_THUMBPOSITION :
case SB_THUMBTRACK :
color[i] = HIWORD (wParam) ;
break ;
default :
break ;
}
SetScrollPos (hwndScroll[i], SB_CTL, color[i], TRUE) ;
wsprintf (szBuffer, TEXT ("%i"), color[i]) ;
SetWindowText (hwndValue[i], szBuffer) ;
DeleteObject ((HBRUSH)
SetClassLong (hwnd, GCL_HBRBACKGROUND, (LONG)
CreateSolidBrush (RGB (color[0], color[1], color[2])))) ;
InvalidateRect (hwnd, &rcColor, TRUE) ;
return 0 ;
case WM_CTLCOLORSCROLLBAR :
i = GetWindowLong ((HWND) lParam, GWL_ID) ;
return (LRESULT) hBrush[i] ; //这里不明白，它返回到哪里去了。
case WM_CTLCOLORSTATIC :
i = GetWindowLong ((HWND) lParam, GWL_ID) ;
if (i >= 3 && i <= 8) // static text controls
{
SetTextColor ((HDC) wParam, crPrim[i % 3]) ;
SetBkColor ((HDC) wParam, GetSysColor (COLOR_BTNHIGHLIGHT));
return (LRESULT) hBrushStatic ;
}
break ;
case WM_SYSCOLORCHANGE :
DeleteObject (hBrushStatic) ;
hBrushStatic = CreateSolidBrush (GetSysColor (COLOR_BTNHIGHLIGHT)) ;
return 0 ;
case WM_DESTROY :
DeleteObject ((HBRUSH)
SetClassLong (hwnd, GCL_HBRBACKGROUND, (LONG)
GetStockObject (WHITE_BRUSH))) ;
for (i = 0 ; i < 3 ; i++)
DeleteObject (hBrush[i]) ;
DeleteObject (hBrushStatic) ;
PostQuitMessage (0) ;
return 0 ;
}
return DefWindowProc (hwnd, message, wParam, lParam) ;
}
LRESULT CALLBACK ScrollProc (HWND hwnd, UINT message,
WPARAM wParam, LPARAM lParam)
{
int id = GetWindowLong (hwnd, GWL_ID) ;
switch (message)
{
case WM_KEYDOWN :
if (wParam == VK_TAB)
SetFocus (GetDlgItem (GetParent (hwnd),
(id + (GetKeyState (VK_SHIFT) < 0 ? 2 : 1)) % 3)) ;
break ;
case WM_SETFOCUS :
idFocus = id ;
break ;
}
return CallWindowProc (OldScroll[id], hwnd, message, wParam, lParam) ;
}
程序上面的WM_CTLCOLORSCROLLBAR 消息中 return (LRESULT) hBrush[i] ; 不明白返回值返回到哪里去
WM_CTLCOLORSTATIC 消息中 return (LRESULT) hBrushStatic ; 也是不明白返回到哪里去。
...全文
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sololie 2013-07-04
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返回到消息的发送的源头处
SendMessage的返回值就是LRESULT，消息处理函数中可以把任意值转为LRESULT返回，可以是个窗口句柄，可以是个结构体指针，或是其他。
// 例如发送WM_CTLCOLORBTN消息来获取一个按钮的画刷句柄
HDC bDc = GetDC(btn1->Handle);
HBRUSH hBrus = (HBRUSH)SendMessage(Handle, WM_CTLCOLORBTN, (WPARAM)bDc, (LPARAM)button1->Handle);
.......
Richardw 2013-07-03
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不是返回哪里去，是返回一个值，只是这个值不只是简单的0或1，而是LRESULT，就是说是一个结果，其实就是长整型……
具体数据分别是hBrush[i]、hBrushStatic
