char szFileName[MAX_PATH]={0}; 
OPENFILENAME openFileName = {0}; 
openFileName.lStructSize = sizeof(OPENFILENAME); 
openFileName.nMaxFile = MAX_PATH;  //這個必須設置，不設置的話不會出現打開文件對話框 
openFileName.lpstrFilter = "文本文件(*.txt)/0*.txt/0所有文件(*.*)/0*.*/0/0"; 
openFileName.lpstrFile = szFileName; 
openFileName.nFilterIndex = 1; 
openFileName.Flags = OFN_PATHMUSTEXIST | OFN_FILEMUSTEXIST; 
 
if (::GetOpenFileName(&openFileName)) 
{ 
    ::MessageBoxA(hwndDlg, openFileName.lpstrFile, "", MB_OK); 
}