C # Call mciSendString to play the audio file,

C # Call mciSendString to play the audio file,

The mciSendString function is a WinAPI used to send string commands to the Media Control Interface (MCI) device.

I. function declaration:

Private static extern long mciSendString (string command, // MCI command string returnString, // buffer that stores feedback int returnSize, // The length of the buffer IntPtr hwndCallback // the handle of the callback window, usually NULL );

 

II. The complete code is as follows. The details are annotated and described. Pay special attention to the thread processing during playback:

Using System; using System. runtime. interopServices; using System. threading; namespace Zhy. MCI {/** call the API function mciSendString to play audio files * mainly includes playing audio files by a specified number of times and loop playback * Author: Zhy * Time: 2015-7-21 */public class MCI {[DllImport ("winmm. dll ")] private static extern long mciSendString (string command, // MCI command string returnString, // buffer that stores feedback int returnSize, // The length of the buffer IntPtr hwndCallback // the handle of the callback window, usually NULL); // If successful, 0 is returned; otherwise, an error code is returned.. /// <Summary> /// play by the specified number of times /// </summary> /// <param name = "file"> </param> private void PlayWait (string file) {/** open device_name type device_type alias device_alias open the device * The name of the device to be used for device_name, usually the file name. * The type device_type device type, such as mpegvideo or waveaudio, can be omitted. * Alias device_alias: Specifies the device alias. You can use other commands to replace the device name. */MciSendString (string. format ("open {0} type mpegvideo alias media", file), null, 0, IntPtr. zero);/** play device_alias from pos1 to pos2 wait repeat start device playback * if it is omitted from, start playing from the current track. * If to is omitted, the playback ends. * If wait is specified, it will not be returned until the Playback command is completed. That is, it indicates that wait will cause thread blocking until the playback is complete * If repeat is specified, it will not stop playing again. * If both wait and repeat are specified, the command will not return. This thread is congested and will usually cause program to lose response. */MciSendString ("play media wait", null, 0, IntPtr. zero);/** close device */mciSendString ("close media", null, 0, IntPtr. zero );} /// <summary> /// loop playback /// </summary> /// <param name = "file"> </param> private void PlayRepeat (string file) {mciSendString (string. format ("open {0} type mpegvideo alias media", file), null, 0, IntPtr. zero); mciSendString ("play media repeat", null, 0, IntPtr. zero);} pr Ivate Thread thread; /// <summary> /// play the audio file /// </summary> /// <param name = "file"> audio file path </param> /// <param name = "times"> playback times, 0: loop playback greater than 0: playback by a specified number of times </param> public void Play (string file, int times) {// The thread is mainly used to solve the problem of Thread blocking when the wait is specified during playback, leading to false UI thread = new Thread (() ==>{ if (times = 0) {PlayRepeat (file);} else if (times> 0) {for (int I = 0; I <times; I ++) {PlayWait (file) ;}}}); // The thread must be a single thread t Hread. setApartmentState (ApartmentState. STA); thread. isBackground = true; thread. start () ;}/// <summary> /// end the playing thread // </summary> public void Exit () {if (thread! = Null) {try {thread. Abort () ;}catch {} thread = null ;}}}}

 

Iii. call:

New MCI (). Play ("audio file path", playback times );