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; }; 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 ); // // Playfilename // This. playfilename. autosize = true; This. playfilename. Location = new system. Drawing. Point (12, 15 ); This. playfilename. Name = "playfilename "; This. playfilename. size = new system. Drawing. Size (0, 17 ); This. playfilename. tabindex = 1; // // Duration // This. Duration. autosize = true; This. Duration. Location = new system. Drawing. Point (15, 51 ); This. Duration. Name = "duration "; This. Duration. size = new system. Drawing. Size (0, 17 ); This. Duration. tabindex = 2; // // Stop // This. Stop. Location = new system. Drawing. Point (282,243 ); This. Stop. Name = "stop "; This. Stop. size = new system. Drawing. Size (81, 24 ); This. Stop. tabindex = 3; This. Stop. Text = "stop "; This. Stop. Click + = new system. eventhandler (this. stop_click ); // // Puase // This. puase. Location = new system. Drawing. Point (198,243 ); This. puase. Name = "puase "; This. puase. size = new system. Drawing. Size (72, 24 ); This. puase. tabindex = 4; This. puase. Text = "puase "; This. puase. Click + = new system. eventhandler (this. puase_click ); // // Currentposition // This. currentposition. autosize = true; This. currentposition. Location = new system. Drawing. Point (15, 87 ); This. currentposition. Name = "currentposition "; This. currentposition. size = new system. Drawing. Size (0, 17 ); This. currentposition. tabindex = 5; // // Timer1 // This. timer1.enabled = true; This. timer1.interval = 1000; This. timer1.tick + = new system. eventhandler (this. timerw.tick ); // // Browserfile // This. browserfile. Location = new system. Drawing. Point (312,165 ); This. browserfile. Name = "browserfile "; This. browserfile. size = new system. Drawing. Size (87, 24 ); This. browserfile. tabindex = 6; This. browserfile. Text = "selectfile "; This. browserfile. Click + = new system. eventhandler (this. browserfile_click ); // // Form1 // This. autoscalebasesize = new system. Drawing. Size (6, 14 ); This. clientsize = new system. Drawing. Size (433,287 ); This. Controls. Add (this. browserfile ); This. Controls. Add (this. currentposition ); This. Controls. Add (this. puase ); This. Controls. Add (this. Stop ); This. Controls. Add (this. duration ); This. Controls. Add (this. playfilename ); This. Controls. Add (this. Play ); This. Name = "form1 "; This. Text = "form1 "; This. resumelayout (false ); } # Endregion /// <Summary> /// Main entry point of the application. /// </Summary> [Stathread] Static void main () { Application. Run (New form1 ()); } // Select MP3 file playback Private void play_click (Object sender, system. eventargs E) { Try { MP. Play (); } Catch { MessageBox. Show ("error! "); } } // Pause the playback. Private void puase_click (Object sender, system. eventargs E) { Try { MP. puase (); } Catch { MessageBox. Show ("error! "); } } // Stop playing Private void stop_click (Object sender, system. eventargs E) { Try { MP. stopt (); } Catch { MessageBox. Show ("error! "); } } // Display the playback progress once per second Private void timerjavastick (Object sender, system. eventargs E) { Currentposition. Text = mp. currentposition. tostring (); } // Browse files Private void browserfile_click (Object sender, system. eventargs E) { Try { Openfiledialog1.filter = "*. MP3 | *. MP3 "; Openfiledialog1.filename = ""; If (openfiledialog1.showdialog () = dialogresult. OK) { MP. filename = openfiledialog1.filename; Playfilename. Text = openfiledialog1.filename; Duration. Text = mp. Duration. tostring (); } } Catch { MessageBox. Show ("error! "); } } } }

This program is compiled in. NET 2003 and Win XP SP1.