Class Design for playing audio files such as MP3 using API functions (C #)

C # No category for playing audio files such as MP3. You need to compile audio files such as MP3 for playing. Program Third-party controls or classes must be used. 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 of clsmci.
///

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 ()
{< br> temstr = "";
temstr = temstr. padleft (128, convert. tochar ("");
ilong = apiclass. mcisendstring ("Pause Media", temstr, temstr. length, 0);
MC. state = state. mpuase;
}< br> private string getcurrpath (string name)
{< br> If (name. length <1) Return "";
name = Name. trim ();
name = Name. substring (0, name. length-1);
return name;
}< br> // total time
Public int duration
{< br> Get
{< br> 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);
}< BR >}

// 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. Ease of Test Media PlaybackCode:
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 of form1.
///

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
//
}

///

/// Clear all resources in use.
///

Protected override void dispose (bool disposing)
{
If (disposing)
{
If (components! = NULL)
{
Components. Dispose ();
}
}
Base. Dispose (disposing );
}

# Region code generated by Windows Form Designer
///

/// The designer supports the required methods-do not use the code editor to modify
/// Content of this method.
///

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

///

/// Main entry point of the application.
///

[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! ");
}
}

}

}