线程无法正常工作 [英] Thread is not working

问题描述

//CLASS:BackGroundMusicGP

// CLASS: BackGroundMusicGP

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.IO;

namespace BackGroundMusicGP
{
    class BkGrndMusic
    {
      private string _command;
     private bool isOpen;
  [DllImport("winmm.dll")]

  private static extern long mciSendString(string strCommand,StringBuilder strReturn,int iReturnLength, IntPtr hwndCallback);

  public void Close()
  {
     _command = "close MediaFile";
     mciSendString(_command, null, 0, IntPtr.Zero);
     isOpen = false;
  }

  public void Open(string sFileName)
  {
     _command = "open \"" + sFileName + "\" type mpegvideo alias MediaFile";
     mciSendString(_command, null, 0, IntPtr.Zero);
     isOpen = true;
  }

  public void Play(bool loop)
  {
     if(isOpen)
     {
        _command = "play MediaFile";
        if (loop)
         _command += " REPEAT";
        mciSendString(_command, null, 0, IntPtr.Zero);
     }
      }
  public void playMusic()
  {
      string path = "E:\\abc\\Habib.mp3";
       string filename = Path.GetFileName(path);
      Open(filename);
      Play(false);
  }
    }
}

////////////////////////

///////////////////////////

public partial class Form1 : Form
   {
       BkGrndMusic objBkMusic;
       int i = 0;
       public Form1()
       {
           InitializeComponent();
           objBkMusic = new BkGrndMusic();
       }
       private void button1_Click(object sender, EventArgs e)
        {
           Thread t = new Thread(new ThreadStart(objBkMusic.playMusic));
            t.Start();  // it doesn't work
           //objBkMusic.playMusic(); // it works
         }

如何使用线程播放背景音乐?当我直接使用类的对象进行调用时，它将起作用.但是，当我使用线程调用时，它不起作用.

How can i play background music using thread? when i call directly using object of the class then it works. But when i call using thread it doesn''t work.

推荐答案

new Thread(new ThreadStart(objBkMusic.playMusic)).Start();通常应该可以正常工作，但是有一个缓存.但是现在有消息队列中的消息被您的线程忽略了. UI线程默认情况下会处理这些消息，但对于非UI线程则不会.您可以在下面的链接中找到出租车:

http://www.pinvoke.net/default.aspx/winmm.mcisendstring [ ^ ]

您可能需要将表单的句柄传递给它，如下所示:

mciSendString(_command, null, 0, Form1.Handle);

http://msdn.microsoft.com/en-us/library/dd757161%28VS. 85％29 [ ^ ]

您当然会在BkGrndMusic类中需要一个可以容纳此句柄的属性，但您可能已经知道了;-)

祝你好运！

new Thread(new ThreadStart(objBkMusic.playMusic)).Start(); should normally work fine, but there is a cache. But there are now messages from the message queue ignored by your thread. The UI thread handles these messages by default but for a non UI thread it is not. You cab look at the link below:

http://www.pinvoke.net/default.aspx/winmm.mcisendstring[^]

You probably need to pass it the handle of your form, like this:

mciSendString(_command, null, 0, Form1.Handle);

http://msdn.microsoft.com/en-us/library/dd757161%28VS.85%29[^]

You would of course need a property in your BkGrndMusic class that can hold this handle, but you probably already got that ;-)

Good luck!

没有错误消息.但是听不到音乐.

@ E.F.奈博尔
您当然会在BkGrndMusic类中需要一个可以容纳此句柄的属性，但您可能已经知道了"

我对此没有足够的知识.能否请您提供代码.我应该更改我的 代码的什么地方?

No error messages. But no music heard.

@E.F. Nijboer
"You would of course need a property in your BkGrndMusic class that can hold this handle, but you probably already got that"

i don''t have sufficient knowledge on that.could you please provide code. where of my code should i change?

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