VC++的SendMessage函数如何利用wParam lParam传递参数

DWORD或其小于等于DWORD（一般为4字节）长度的变量直接传再强转：
unsigned int a =12345;
unsigned int* b = &a;
SendMessage(DWORD(a), DWORD(b));

OnMessage(DWORD wParam, DWORD lParam)
{
unsigned int a =(unsigned int)wParam;
unsigned int* b = (unsigned int*)lParam;
...
}
复杂数据传指针再强转（或提升）：
struct a_t
{
int aa;
char ab;
};

a_t a;

SendMessage(DWORD(&a), DWORD(0));

OnMessage(DWORD wParam, DWORD lParam)
{
a_t* pa =(a_t*)wParam;
cout << pa->aa << endl;
...
}

转自：http://zhidao.baidu.com/question/69002874.html