编程调节Win7/Win8系统音量的一种方法

#include <windows.h> 
#include <mmdeviceapi.h> 
#include <endpointvolume.h>
#include <audioclient.h>


//参数:
//    -2 恢复静音
//    -1 静音
//    0~100:音量比例
bool SetVolumeLevel(int level)
{
    HRESULT hr;
    IMMDeviceEnumerator* pDeviceEnumerator=0;
    IMMDevice* pDevice=0;
    IAudioEndpointVolume* pAudioEndpointVolume=0;
    IAudioClient* pAudioClient=0;

    try{
        hr = CoCreateInstance(__uuidof(MMDeviceEnumerator),NULL,CLSCTX_ALL,__uuidof(IMMDeviceEnumerator),(void**)&pDeviceEnumerator);
        if(FAILED(hr)) throw "CoCreateInstance";
        hr = pDeviceEnumerator->GetDefaultAudioEndpoint(eRender,eMultimedia,&pDevice);
        if(FAILED(hr)) throw "GetDefaultAudioEndpoint";
        hr = pDevice->Activate(__uuidof(IAudioEndpointVolume),CLSCTX_ALL,NULL,(void**)&pAudioEndpointVolume);
        if(FAILED(hr)) throw "pDevice->Active";
        hr = pDevice->Activate(__uuidof(IAudioClient),CLSCTX_ALL,NULL,(void**)&pAudioClient);
        if(FAILED(hr)) throw "pDevice->Active";

        if(level==-2){
            hr = pAudioEndpointVolume->SetMute(FALSE,NULL);
            if(FAILED(hr)) throw "SetMute";
        }else if(level==-1){
            hr = pAudioEndpointVolume->SetMute(TRUE,NULL);
            if(FAILED(hr)) throw "SetMute";
        }else{
            if(level<0 || level>100){
                hr = E_INVALIDARG;
                throw "Invalid Arg";
            }

            float fVolume;
            fVolume = level/100.0f;
            hr = pAudioEndpointVolume->SetMasterVolumeLevelScalar(fVolume,&GUID_NULL);
            if(FAILED(hr)) throw "SetMasterVolumeLevelScalar";

            pAudioClient->Release();
            pAudioEndpointVolume->Release();
            pDevice->Release();
            pDeviceEnumerator->Release();
            return true;
        }
    }
    catch(...){
        if(pAudioClient) pAudioClient->Release();
        if(pAudioEndpointVolume) pAudioEndpointVolume->Release();
        if(pDevice) pDevice->Release();
        if(pDeviceEnumerator) pDeviceEnumerator->Release();
        throw;
    }
    return false;
}



int main()
{
    CoInitialize(0);
    try{
        //3秒后静音
        Sleep(3000);
        SetVolumeLevel(-1);
        //3秒后恢复静音
        Sleep(3000);
        SetVolumeLevel(-2);
        //调节音量
        Sleep(3000);
        SetVolumeLevel(10);
        Sleep(3000);
        SetVolumeLevel(30);
        Sleep(3000);
        SetVolumeLevel(20);
    }
    catch(...){
        //错误处理...
    }
    CoUninitialize();
    return 0;
}