先引用 System.Runtime.InteropServices 命名空间。
api to control volumn
//第一个参数是波形文件输出设备标识符,可以用0,表示使用首选设备;
//第二个参数为音量大小,是一个32位的整数,低16位表示左声道的音量,高16位表示右声道的音量,范围从0x0000~0xFFFF
[DllImport("winmm.dll")]
public static extern long waveOutSetVolume(UInt32 deviceID, UInt32 Volume);
[DllImport("winmm.dll")]
public static extern long waveOutGetVolume(UInt32 deviceID, out UInt32 Volume);
//第一个参数是波形文件输出设备标识符,可以用0,表示使用首选设备;
//第二个参数为音量大小,是一个32位的整数,低16位表示左声道的音量,高16位表示右声道的音量,范围从0x0000~0xFFFF
[DllImport("winmm.dll")]
public static extern long waveOutSetVolume(UInt32 deviceID, UInt32 Volume);
[DllImport("winmm.dll")]
public static extern long waveOutGetVolume(UInt32 deviceID, out UInt32 Volume);
在Form上拖一个 TrackBar 控件
获取系统音量
private void GetVolume()
{
UInt32 d,v;
d = 0;
long i = ClaCommon.waveOutGetVolume(d,out v);
UInt32 vleft = v & 0xFFFF;
UInt32 vright = (v & 0xFFFF0000) >> 16;
trackBar1.Value = (int.Parse(vleft.ToString()) | int.Parse(vright.ToString())) * (this.trackBar1.Maximum - this.trackBar1.Minimum) / 0xFFFF;
}
private void GetVolume()
{
UInt32 d,v;
d = 0;
long i = ClaCommon.waveOutGetVolume(d,out v);
UInt32 vleft = v & 0xFFFF;
UInt32 vright = (v & 0xFFFF0000) >> 16;
trackBar1.Value = (int.Parse(vleft.ToString()) | int.Parse(vright.ToString())) * (this.trackBar1.Maximum - this.trackBar1.Minimum) / 0xFFFF;
}
在trackbar的 valuechanged 或 scroll 事件里实现音量调节。
音量调节
private void trackBar1_ValueChanged(object sender, EventArgs e)
{
UInt32 Value = (System.UInt32)((double)0xffff * (double)trackBar1.Value / (double)(trackBar1.Maximum - trackBar1.Minimum));//先把trackbar的value值映射到0x0000~0xFFFF范围
//限制value的取值范围
if (Value < 0) Value = 0;
if (Value > 0xffff) Value = 0xffff;
UInt32 left = (System.UInt32)Value;//左声道音量
UInt32 right = (System.UInt32)Value;//右
waveOutSetVolume(0, left << 16 | right); //"<<"左移,“|”逻辑或运算
}
private void trackBar1_ValueChanged(object sender, EventArgs e)
{
UInt32 Value = (System.UInt32)((double)0xffff * (double)trackBar1.Value / (double)(trackBar1.Maximum - trackBar1.Minimum));//先把trackbar的value值映射到0x0000~0xFFFF范围
//限制value的取值范围
if (Value < 0) Value = 0;
if (Value > 0xffff) Value = 0xffff;
UInt32 left = (System.UInt32)Value;//左声道音量
UInt32 right = (System.UInt32)Value;//右
waveOutSetVolume(0, left << 16 | right); //"<<"左移,“|”逻辑或运算
}