【VC++】动态调用链接库

#include "stdafx.h"
#include <windows.h>
#include <windowsx.h>
#include "resource.h"
#include "MainDlg.h"
typedef int(_cdecl* FunctionAdd)(int,int);
/*
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*/
BOOL WINAPI Main_Proc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch(uMsg)
{
HANDLE_MSG(hWnd, WM_INITDIALOG, Main_OnInitDialog);
HANDLE_MSG(hWnd, WM_COMMAND, Main_OnCommand);
HANDLE_MSG(hWnd,WM_CLOSE, Main_OnClose);
}
return FALSE;
}
BOOL Main_OnInitDialog(HWND hwnd, HWND hwndFocus, LPARAM lParam)
{
return TRUE;
}
void Main_OnCommand(HWND hwnd, int id, HWND hwndCtl, UINT codeNotify)
{
switch(id)
{
case IDC_OK:
{
HMODULE hModule;
FunctionAdd add;
hModule = LoadLibrary("Newdll.dll");
//调试时hModule为0x10000000
//LoadLibrary返回的就是dll的句柄
//参数可以是相对路径，也可以是绝对路径
if(NULL==hModule )
{
MessageBox(hwnd,TEXT("加载dll失败"),TEXT("错误"),MB_OK);

}
add =(FunctionAdd)GetProcAddress(hModule,"add");
if(NULL==add)
{
MessageBox(hwnd,TEXT("加载dll失败"),TEXT("错误"),MB_OK);

}
int r=add(1,1);
TCHAR msg[256];
wsprintf(msg,"1+1=%i",r);
MessageBox(hwnd,msg,TEXT("错误"),MB_OK);
FreeLibrary(hModule);

}
break;
default:
break;
}
}
void Main_OnClose(HWND hwnd)
{
EndDialog(hwnd, 0);
}