C # Two ways to control the volume/microphone size of the system

Scenario: You need to control the volume when doing the playback device, the following methods will meet your requirements

Method One: Change the system volume settings

        [DllImport ("User32.dll")] static extern void keybd_event (byte bvk, byte Bscan, UInt32 dwFlags, UInt32 dwext        Rainfo);        [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>//Change system volume size, increase///</summary> public void Volumeup () {k            Eybd_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>//Change the system volume size to decrease///</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>//Change the system volume, mute///</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); }

Method Two: Change the program volume, but do not change the system volume settings

        [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>///volume control, but do not change system volume settings///</summary> public int Volumesize {            get {return volumesize;}        set {volumesize = value;} } public void Setcurrentvolume () {if (Volumesize < 0) {Volumesize            = 0;            } if (Volumesize >) {volumesize = 100;                                 } system.uint32 Value = (system.uint32) (double) 0xFFFF * (double) volumesize/(double) (volumemaxscope-v Olumeminscope)), or//the value of TrackBar is first mappedShot to 0X0000~0XFFFF range//Limit value range if (value < 0) {value = 0;            } if (Value > 0xFFFF) {value = 0xFFFF;            } System.UInt32 left = (system.uint32) value;//The right-hand channel volume System.UInt32 r = (system.uint32) value;// Waveoutsetvolume (0, left << | right); "<<" shift Left, "|" Logical OR Operation}

C # Two ways to control the volume/microphone size of the system