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一个listbox控件无法显示高手帮小弟

发布时间: 2012-03-14 12:01:12 作者: rapoo

一个listbox控件无法显示,高手帮我看看。 - C++ Builder / Windows SDK/API
#include <windows.h>

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

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
PSTR szCmdLine, int iCmdShow)
{
static char szAppName[] = "BtnLook" ;
HWND hwnd ;
MSG msg ;
WNDCLASSEX wndclass ;

wndclass.cbSize = sizeof (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.hIconSm = LoadIcon (NULL, IDI_APPLICATION) ;

RegisterClassEx (&wndclass) ;

hwnd = CreateWindow (szAppName, "listbox",
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 iMsg, WPARAM wParam, LPARAM lParam)
{
static HWND hwnda;
switch (iMsg)
{
static int a,b;
a=LOWORD(GetDialogBaseUnits());
b=HIWORD(GetDialogBaseUnits());
case WM_CREATE :
hwnda=CreateWindow("listbox",NULL,
WS_CHILD|WS_VISIBLE|LBS_STANDARD,
0,0,a*30,b*5,hwnd,(HMENU)0,
(HINSTANCE)GetWindowLong(hwnd,GWL_HINSTANCE),
NULL);
SendMessage(hwnda,LB_ADDSTRING,0,(LPARAM)TEXT("1"));
return 0 ;

case WM_SIZE :

return 0 ;

case WM_PAINT :

return 0 ;


case WM_COMMAND :
{
if(LOWORD(wParam)==0)
{
int i=SendMessage(hwnda,LB_GETCURSEL,0,0);
switch(i)
{
case 0:
MessageBox(hwnd,TEXT(""),TEXT(""),MB_OK);
break;
}

}
break ;
}
case WM_DESTROY :
PostQuitMessage (0) ;
return 0 ;
}
return DefWindowProc (hwnd, iMsg, wParam, lParam) ;
}
一个listbox控制不知为何无法显示控件,程序可以运行通过。

[解决办法]
switch里面的这三句:
static int a,b;
a=LOWORD(GetDialogBaseUnits());
b=HIWORD(GetDialogBaseUnits());

是执行不到的。放到WM_CREATE的case中。如:

C/C++ code
case WM_CREATE:    static int a, b;    a = LOWORD(GetDialogBaseUnits());    b = HIWORD(GetDialogBaseUnits());    hwnda = CreateWindow("listbox"...... 

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