場景:在做播放設備的時候需要控制音量的大小，下面幾種方法將滿足你的要求
方法一: 改變系統音量設置
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[DllImport("user32.dll")]
static extern void keybd_event(byte bVk, byte bScan, UInt32 dwFlags, UInt32 dwExtraInfo);
[DllImport("user32.dll")]
static extern Byte MapVirtualKey(UInt32 uCode, UInt32 uMapType);
private const byte VK_VOLUME_MUTE = 0xAD;
private const byte VK_VOLUME_DOWN = 0xAE;
private const byte VK_VOLUME_UP = 0xAF;
private const UInt32 KEYEVENTF_EXTENDEDKEY = 0x0001;
private const UInt32 KEYEVENTF_KEYUP = 0x0002;
/// <summary>
/// 改變系統音量大小，增加
/// </summary>
public void VolumeUp()
{
keybd_event(VK_VOLUME_UP, MapVirtualKey(VK_VOLUME_UP, 0), KEYEVENTF_EXTENDEDKEY, 0);
keybd_event(VK_VOLUME_UP, MapVirtualKey(VK_VOLUME_UP, 0), KEYEVENTF_EXTENDEDKEY | KEYEVENTF_KEYUP, 0);
}
/// <summary>
/// 改變系統音量大小，減小
/// </summary>
public void VolumeDown()
{
keybd_event(VK_VOLUME_DOWN, MapVirtualKey(VK_VOLUME_DOWN, 0), KEYEVENTF_EXTENDEDKEY, 0);
keybd_event(VK_VOLUME_DOWN, MapVirtualKey(VK_VOLUME_DOWN, 0), KEYEVENTF_EXTENDEDKEY | KEYEVENTF_KEYUP, 0);
}
/// <summary>
/// 改變系統音量大小，靜音
/// </summary>
public void Mute()
{
keybd_event(VK_VOLUME_MUTE, MapVirtualKey(VK_VOLUME_MUTE, 0), KEYEVENTF_EXTENDEDKEY, 0);
keybd_event(VK_VOLUME_MUTE, MapVirtualKey(VK_VOLUME_MUTE, 0), KEYEVENTF_EXTENDEDKEY | KEYEVENTF_KEYUP, 0);
}
方法二: 改變程序音量，但不改變系統音量設置
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[DllImport("Winmm.dll")]
private static extern int waveOutSetVolume(int hwo, System.UInt32 pdwVolume);
[DllImport("Winmm.dll")]
private static extern uint waveOutGetVolume(int hwo, out System.UInt32 pdwVolume);
#region
private int volumeMinScope = 0;
private int volumeMaxScope = 100;
private int volumeSize = 100;
/// <summary>
/// 音量控制，但不改變系統音量設置
/// </summary>
public int VolumeSize
{
get { return volumeSize; }
set { volumeSize = value; }
}
public void SetCurrentVolume()
{
if (volumeSize < 0)
{
volumeSize = 0;
}
if (volumeSize > 100)
{
volumeSize = 100;
}
System.UInt32 Value = (System.UInt32)((double)0xffff * (double)volumeSize / (double)(volumeMaxScope - v
olumeMinScope));//先把trackbar的value值映射到0x0000～0xFFFF范圍
//限制value的取值范圍
if (Value < 0)
{
Value = 0;
}
if (Value > 0xffff)
{
Value = 0xffff;
}
System.UInt32 left = (System.UInt32)Value;//左聲道音量
System.UInt32 right = (System.UInt32)Value;//右
waveOutSetVolume(0, left << 16 | right); //"<<"左移，“|”邏輯或運算
}
