Question

c#中如何用trackbar控件实现音量调节

Answer 1

#region 音量
[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);

private void GetSoundVolume()
{
UInt32 d, v;
d = 0;
long i = waveOutGetVolume(d, out v);
UInt32 vleft = v & 0xFFFF;
UInt32 vright = (v & 0xFFFF0000) >> 16;
trackBar2.Value = (int.Parse(vleft.ToString()) | int.Parse(vright.ToString())) * (this.trackBar2.Maximum - this.trackBar2.Minimum) / 0xFFFF;
}

// 滑块值改变时，修改音量值
private void trackBar2_Scroll(object sender, EventArgs e)
{
UInt32 Value = (System.UInt32)((double)0xffff * (double)trackBar2.Value / (double)(trackBar2.Maximum - trackBar2.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
}
#endregion