Question

C++高手进，帮小弟看看（基于WINMAIN的窗口）代码为什么运行后不显示图片

为什么运行后，窗口中没有图片显示？
位图名“bg.bmp”
大虾帮忙看看！
代码如下：

#include "StdAfx.h"
#include "resource.h"

#define MAX_LOADSTRING 100
HINSTANCE hInst;
HBITMAP hbmp;
HDC mdc;
TCHAR szTitle[MAX_LOADSTRING];
TCHAR szWindowClass[MAX_LOADSTRING];

ATOM MyRegisterClass(HINSTANCE hInstance);
BOOL InitInstance(HINSTANCE, int);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK About(HWND, UINT, WPARAM, LPARAM);
void MyPaint(HDC hdc);

int APIENTRY WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
MSG msg;

MyRegisterClass(hInstance);

if (!InitInstance (hInstance, nCmdShow))
{
return FALSE;
}
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}
ATOM MyRegisterClass(HINSTANCE hInstance)
{
WNDCLASSEX wcex;
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = (WNDPROC)WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = NULL;
wcex.hCursor = NULL;
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wcex.lpszMenuName = NULL;
wcex.lpszClassName = "canvas";
wcex.hIconSm = NULL;
return RegisterClassEx(&wcex);
}

BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
HWND hWnd;
HDC hdc;

hInst = hInstance;
hWnd = CreateWindow("canvas","绘图窗口", WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);

if (!hWnd)
{
return FALSE;
}

MoveWindow(hWnd,10,10,600,450,true);
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);

hdc=GetDC(hWnd);
mdc=CreateCompatibleDC(hdc);

hbmp=(HBITMAP)LoadImage(NULL,"bg.bmp",IMAGE_BITMAP,600,450,LR_LOADFROMFILE);
SelectObject(mdc,hbmp);
MyPaint(hdc);
ReleaseDC(hWnd,hdc);

return TRUE;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
PAINTSTRUCT ps;
HDC hdc;

switch (message)
{
case WM_PAINT:
hdc = BeginPaint(hWnd, &ps);
MyPaint(hdc);
EndPaint(hWnd, &ps);
break;
case WM_DESTROY:
DeleteDC(mdc);
DeleteObject(hbmp);
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}
void MyPaint(HDC hdc)
{
BitBlt(hdc,0,0,600,450,mdc,0,0,SRCCOPY);
}

Answer 1

程序是对的；
是不是图片放错文件夹了？

load时加个判断
hbmp=(HBITMAP)LoadImage(NULL,"bg.bmp",IMAGE_BITMAP,600,450,LR_LOADFROMFILE);
if (!hbmp)
{
MessageBox( NULL, "装载图片失败", NULL, MB_OK );
return FALSE;
}