在Windows XP中,使用Delphi,如何获取主卷？
我知道我可以使用keybd_event(VK_VOLUME_UP,1,0)设置和发送击键;和keybd_event(VK_VOLUME_DOWN,0);但我不知道如何获取卷的实际值.
解决方法
以下是对找到的示例代码
here的一点修改(记入Thomas Stutz).这个例子设置了麦克风音量.我刚刚修改了组件类型 – 扬声器目的地而不是麦克风源,并用
mixerGetControlDetails替换了mixerSetControlDetails,当然把setter变成了一个getter.在我测试的几个系统(XPSp3,XPSp2,W2K,98)上,它似乎有效.函数的返回是第一个(默认)混音器中的扬声器 – 值为0-65535,按钮处理程序中的“ShowMessage”将其更改为百分比.但是不要问我有关它的更多细节,我真的没有使用混音器api的经验.请参阅
here f.i.,尽管这篇文章看起来对我来说似乎很全面.
function GetSpeakerVolume(var bValue: Word): Boolean;
var {0..65535}
hMix: HMIXER;
mxlc: MIXERLINECONTROLS;
mxcd: TMIXERCONTROLDETAILS;
vol: TMIXERCONTROLDETAILS_UNSIGNED;
mxc: MIXERCONTROL;
mxl: TMixerLine;
intRet: Integer;
nMixerDevs: Integer;
begin
Result := False;
// Check if Mixer is available
nMixerDevs := mixerGetNumDevs();
if (nMixerDevs < 1) then
Exit;
// open the mixer
intRet := mixerOpen(@hMix,0);
if intRet = MMSYSERR_NOERROR then
begin
mxl.dwComponentType := MIXERLINE_COMPONENTTYPE_DST_SPEAKERS;
mxl.cbStruct := SizeOf(mxl);
// get line info
intRet := mixerGetLineInfo(hMix,@mxl,MIXER_GETLINEINFOF_COMPONENTTYPE);
if intRet = MMSYSERR_NOERROR then
begin
ZeroMemory(@mxlc,SizeOf(mxlc));
mxlc.cbStruct := SizeOf(mxlc);
mxlc.dwLineID := mxl.dwLineID;
mxlc.dwControlType := MIXERCONTROL_CONTROLTYPE_VOLUME;
mxlc.cControls := 1;
mxlc.cbmxctrl := SizeOf(mxc);
mxlc.pamxctrl := @mxc;
intRet := mixerGetLineControls(hMix,@mxlc,MIXER_GETLINECONTROLSF_ONEBYTYPE);
if intRet = MMSYSERR_NOERROR then
begin
ZeroMemory(@mxcd,SizeOf(mxcd));
mxcd.dwControlID := mxc.dwControlID;
mxcd.cbStruct := SizeOf(mxcd);
mxcd.cMultipleItems := 0;
mxcd.cbDetails := SizeOf(vol);
mxcd.paDetails := @vol;
mxcd.cChannels := 1;
intRet := mixerGetControlDetails(hMix,@mxcd,MIXER_GETCONTROLDETAILSF_VALUE);
if intRet <> MMSYSERR_NOERROR then
ShowMessage('GetControlDetails Error')
else begin
bValue := vol.dwValue;
Result := True;
end;
end
else
ShowMessage('GetLineInfo Error');
end;
intRet := mixerClose(hMix);
end;
end;
procedure TForm1.Button1Click(Sender: TObject);
var
Vol: Word;
begin
if GetSpeakerVolume(Vol) then
ShowMessage(IntToStr(Round(Vol * 100 / 65535)));
end;