摘要

mciSendString 播放MP3

MCI(Media Control Interface，媒体控制接口)函数中，有些只适用于一种接口方式，有些则两种接口都可以用。mciSendString只适用于命令串接口方式（命令串中不区分大小写）。

正文

声明

C#
[DllImport("winmm.dll")]
private static extern uint mciSendString(string command,StringBuilder returnValue,int returnLength,IntPtr winHandle);





### **基本功能实现**

注意temp_alias 这个是对应别名

```C#
/// <summary>
/// 播放
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnPlay_Click(object sender, EventArgs e)
{
    StringBuilder path = new StringBuilder();
    path.Append(@"D:\MyProject\白泽\Bz.Platform\wavplay\a.mp3");
    mciSendString(@"close temp_alias", null, 0, IntPtr.Zero);
    mciSendString(@"open """ + path + @""" alias temp_alias", null, 0, IntPtr.Zero);
    mciSendString("play temp_alias repeat", null, 0, IntPtr.Zero);
}
/// <summary>
/// 停止
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnStop_Click(object sender, EventArgs e)
{
    mciSendString("stop temp_alias", new StringBuilder(), 0, IntPtr.Zero);
}
/// <summary>
/// 暂停
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnPause_Click(object sender, EventArgs e)
{
    mciSendString("pause temp_alias", new StringBuilder(), 0, IntPtr.Zero);
}
/// <summary>
/// 继续
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnResume_Click(object sender, EventArgs e)
{
    mciSendString("resume temp_alias", new StringBuilder(), 0, IntPtr.Zero);
}
/// <summary>
/// 取得音频长度
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnLength_Click(object sender, EventArgs e)
{
    StringBuilder lengthBuf = new StringBuilder(32);
    mciSendString("status temp_alias length", lengthBuf, lengthBuf.Capacity, IntPtr.Zero);
    long len = long.Parse(lengthBuf.ToString());
    MessageBox.Show((len / 1000.0f/60.0f).ToString());
}
//调整声音1-1000
private void tbVoice_Scroll(object sender, EventArgs e)
{
    StringBuilder sb = new StringBuilder(32);
    sb.Append(tbVoice.Value.ToString());
    mciSendString("setaudio temp_alias volume to "+ tbVoice.Value.ToString(), sb, sb.Capacity, IntPtr.Zero);
}
/// <summary>
/// 取得当前位置
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnCurrent_Click(object sender, EventArgs e)
{
    StringBuilder lengthBuf = new StringBuilder(32);
    mciSendString("status temp_alias position", lengthBuf, lengthBuf.Capacity, IntPtr.Zero);
    long len = long.Parse(lengthBuf.ToString());
    MessageBox.Show((len / 1000.0f / 60.0f).ToString());
}

总结

在本文中，我们介绍了如何在 C# 中使用 mciSendString 函数播放声音。我们声明了 mciSendString 函数，并演示了一些常用的属性和方法，包括播放声音、暂停和继续播放、停止播放以及获取声音状态。