如何在vista / xp中调整主卷 [英] how to adjust master volume in vista/xp
本文介绍了如何在vista / xp中调整主卷的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我想按照vista和xp中的Get / SetMasterVolume进行编程调整?使用mmsystem单元?
i want to adjust the volume programatically like Get/SetMasterVolume in vista and xp? using mmsystem unit?
推荐答案
这是一个通用api的音频实现:MMDevApi
Here's the implementation of a general purpose api for audio: MMDevApi
和一个按钮的例子
unit Unit33;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, MMDevApi, ActiveX, StdCtrls;
type
TForm33 = class(TForm)
Button1: TButton;
procedure FormCreate(Sender: TObject);
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form33: TForm33;
endpointVolume: IAudioEndpointVolume = nil;
implementation
{$R *.dfm}
procedure TForm33.Button1Click(Sender: TObject);
var
VolumeLevel: Single;
begin
if endpointVolume = nil then Exit;
VolumeLevel := 0.50;
endpointVolume.SetMasterVolumeLevelScalar(VolumeLevel, nil);
Caption := Format('%1.8f', [VolumeLevel])
end;
procedure TForm33.FormCreate(Sender: TObject);
var
deviceEnumerator: IMMDeviceEnumerator;
defaultDevice: IMMDevice;
begin
CoCreateInstance(CLASS_IMMDeviceEnumerator, nil, CLSCTX_INPROC_SERVER, IID_IMMDeviceEnumerator, deviceEnumerator);
deviceEnumerator.GetDefaultAudioEndpoint(eRender, eConsole, defaultDevice);
defaultDevice.Activate(IID_IAudioEndpointVolume, CLSCTX_INPROC_SERVER, nil, endpointVolume);
end;
end.
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