openfilename打开文件对话框的使用

因为没设置nMaxFile，一直不出现对话框

					char szFileName[MAX_PATH]={0};
					OPENFILENAME openFileName = {0};
					openFileName.lStructSize = sizeof(OPENFILENAME);
					openFileName.nMaxFile = MAX_PATH;  //这个必须设置，不设置的话不会出现打开文件对话框
					openFileName.lpstrFilter = "文本文件(*.txt)*.txt所有文件(*.*)*.*";
					openFileName.lpstrFile = szFileName;
					openFileName.nFilterIndex = 1;
					openFileName.Flags = OFN_PATHMUSTEXIST | OFN_FILEMUSTEXIST;

					if (::GetOpenFileName(&openFileName))
					{
						::MessageBoxA(hwndDlg, openFileName.lpstrFile, "", MB_OK);
					}