.NET Framework Solution In Search of the Lost Win32 API phần 7

bởi vì Windows sử dụng một phương pháp rất cơ bản để xác định làm thế nào để đánh giá các yếu tố bảo mật. Bạn sẽ cần đến chương trình xung quanh những vấn đề này để lấy được các kết quả được tìm thấy trong các tiện ích Windows khác nhau. SACL có cùng một vấn đề, nhưng nó chỉ ảnh hưởng đến kiểm toán, | Opening a File Locate the data area of the file. mmioFOURCC d a t a Result mmioDescend MMIOHandle ref Child ref Parent Check the results. if Result MMSYSERR_NOERROR Display an error message. Unable to find waveform data. File Error Close the open MMIO file handle. mmioClose MMIOHandle 0 return Read the data from the file. BytesToRead WaveData BytesToRead if mmioRead MMIOHandle WaveData BytesToRead BytesToRead Display an error message. File is truncated. File Error Free the pointer memory. WaveData Close the open MMIO file handle. mmioClose MMIOHandle 0 return Close the open MMIO file handle. mmioClose MMIOHandle 0 Enable the Play button. true else If the user didn t select anything return. return This example requires quite a bit of code just to open the file but that s really the hardest part of the task. The code begins by creating several modulewide variables. Most of these variables provide general pointers to the 247 Opening a File data used by the rest of the application so they re legitimately modulewide. I ve attempted to keep the number of these variables small. The btnOpen_Click method begins by creating an Open WAV File Dialog that enables the user to select a file from the drive as shown in Figure . This is one of the few standard pieces of code in the example but a necessary piece in this case. If the user selects a file then the rest of the code will open it. Otherwise the btnOpen_Click method exits without doing anything. Figure The application provides a custom dialog box for selecting the WAV file. Once the code has a filename to use it uses the mmioOpen function to open the file. The multimedia input output mmio functions enable you to open read write and close files for use with multimedia functions. We ll see .