C # Use APIs to play MP3 and other audio files

C # No class is provided for playing audio files such as MP3. To write audio file programs such as MP3, you must use third-party controls or classes. This article uses the API function mciSendString to compile a class for playing audio files such as MP3.

The source code is as follows:

1. Media playing class composed of mciSendString using the API function.

Using System; Using System. Runtime. InteropServices; Using System. Text; Using System. IO; Namespace clsMCIPlay { /// <Summary> /// Summary of clsMci. /// </Summary> Public class clsMCI { Public clsMCI () { // // TODO: add the constructor logic here // } // Define the string variable used by the API Function [Financialas (UnmanagedType. ByValTStr, SizeConst = 260)] Private string Name = ""; [Financialas (UnmanagedType. ByValTStr, SizeConst = 128)] Private string durLength = ""; [Financialas (UnmanagedType. LPTStr, SizeConst = 128)] Private string TemStr = ""; Int ilong; // Defines the enumerated variables of the playback status. Public enum State { MPlaying = 1, MPuase = 2, MStop = 3 }; // Structure Variable Public struct structMCI { Public bool bMut; Public int iDur; Public int iPos; Public int iVol; Public int iBal; Public string iName; Public State state; }; Public structMCI mc = new structMCI (); // Obtain the playback file attributes Public string FileName { Get { Return mc. iName; } Set { // ASCIIEncoding asc = new ASCIIEncoding (); Try { TemStr = ""; TemStr = TemStr. PadLeft (127, Convert. ToChar ("")); Name = Name. PadLeft (260, Convert. ToChar ("")); Mc. iName = value; Ilong = APIClass. getw.pathname (mc. iName, Name, Name. Length ); Name = GetCurrPath (Name ); // Name = "open" + Convert. ToChar (34) + Name + Convert. ToChar (34) + "alias media "; Name = "open" + Convert. ToChar (34) + Name + Convert. ToChar (34) + "alias media "; Ilong = APIClass. mciSendString ("close all", TemStr, TemStr. Length, 0 ); Ilong = APIClass. mciSendString (Name, TemStr, TemStr. Length, 0 ); Ilong = APIClass. mciSendString ("set media time format milliseconds", TemStr, TemStr. Length, 0 ); Mc. state = State. mStop; } Catch { MessageBox. Show ("error! "); } } } // Play Public void play () { TemStr = ""; TemStr = TemStr. PadLeft (127, Convert. ToChar ("")); APIClass. mciSendString ("play media", TemStr, TemStr. Length, 0 ); Mc. state = State. mPlaying; } // Stop Public void StopT () { TemStr = ""; TemStr = TemStr. PadLeft (128, Convert. ToChar ("")); Ilong = APIClass. mciSendString ("close media", TemStr, 128, 0 ); Ilong = APIClass. mciSendString ("close all", TemStr, 128, 0 ); Mc. state = State. mStop; } Public void Puase () { TemStr = ""; TemStr = TemStr. PadLeft (128, Convert. ToChar ("")); Ilong = APIClass. mciSendString ("pause media", TemStr, TemStr. Length, 0 ); Mc. state = State. mPuase; } Private string GetCurrPath (string name) { If (name. Length <1) return ""; Name = name. Trim (); Name = name. Substring (0, name. Length-1 ); Return name; } // Total time Public int Duration { Get { DurLength = ""; DurLength = durLength. PadLeft (128, Convert. ToChar ("")); APIClass. mciSendString ("status media length", durLength, durLength. Length, 0 ); DurLength = durLength. Trim (); If (durLength = "") return 0; Return (int) (Convert. ToDouble (durLength)/1000f ); } } // Current time Public int CurrentPosition { Get { DurLength = ""; DurLength = durLength. PadLeft (128, Convert. ToChar ("")); APIClass. mciSendString ("status media position", durLength, durLength. Length, 0 ); Mc. iPos = (int) (Convert. ToDouble (durLength)/1000f ); Return mc. iPos; } } } Public class APIClass { [DllImport ("kernel32.dll", CharSet = CharSet. Auto)] Public static extern int getaskpathname ( String lpszLongPath, String delimiter file, Int cchBuffer ); [DllImport ("winmm. dll", EntryPoint = "mciSendString", CharSet = CharSet. Auto)] Public static extern int mciSendString ( String lpstrCommand, String lpstrReturnString, Int uReturnLength, Int hwndCallback ); } }

Ii. Simple code used to test media playback:

Using System; Using System. Drawing; Using System. Collections; Using System. ComponentModel; Using System. Windows. Forms; Using System. Data; Using System. Runtime. InteropServices; Using System. Text; Using System. IO; Using clsMCIPlay; Namespace MCIPlay { /// <Summary> /// Summary of Form1. /// </Summary> Public class Form1: System. Windows. Forms. Form { Private System. ComponentModel. IContainer components; Private System. Windows. Forms. Timer timer1; Private System. Windows. Forms. Button Play; Private System. Windows. Forms. Button Stop; Private System. Windows. Forms. Button Puase; Private System. Windows. Forms. Label PlayFileName; Private System. Windows. Forms. Label Duration; Private System. Windows. Forms. Label CurrentPosition; Private System. Windows. Forms. OpenFileDialog openFileDialog1; Private System. Windows. Forms. Button BrowserFile; ClsMCI mp = new clsMCI (); Public Form1 () { // // Required for Windows Form Designer support // InitializeComponent (); // // TODO: add Any constructor code after InitializeComponent calls // } /// <Summary> /// Clear all resources in use. /// </Summary> Protected override void Dispose (bool disposing) { If (disposing) { If (components! = Null) { Components. Dispose (); } } Base. Dispose (disposing ); } # Region code generated by Windows Form Designer /// <Summary> /// The designer supports the required methods-do not use the code editor to modify /// Content of this method. /// </Summary> Private void InitializeComponent () { This. components = new System. ComponentModel. Container (); This. Play = new System. Windows. Forms. Button (); This. PlayFileName = new System. Windows. Forms. Label (); This. Duration = new System. Windows. Forms. Label (); This. Stop = new System. Windows. Forms. Button (); This. Puase = new System. Windows. Forms. Button (); This. CurrentPosition = new System. Windows. Forms. Label (); This. timer1 = new System. Windows. Forms. Timer (this. components ); This. openFileDialog1 = new System. Windows. Forms. OpenFileDialog (); This. BrowserFile = new System. Windows. Forms. Button (); This. SuspendLayout (); // // Play // This. Play. Location = new System. Drawing. Point (102,243 ); This. Play. Name = "Play "; This. Play. Size = new System. Drawing. Size (78, 24 ); This. Play. TabIndex = 0; This. Play. Text = "Play "; This. Play. Click + = new System. EventHandler (this. Play_Click );