MCI_PLAY_PARMS dwCallback 如何获取回调事件
我的问题就是使用mciSendCommand如何获取当前播放音乐时间点，精度是毫秒。
回调事件如何捕捉，请高手指点，困惑了很久了。谢谢！

代码如下

unit mciPas;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs,mmsystem, StdCtrls;

type
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
mciOpenParms: MCI_OPEN_PARMS;
m_MCIDeviceID: MCIDEVICEID;
mciPlayParms:MCI_PLAY_PARMS;
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

//初始化参数
procedure TForm1.Button1Click(Sender: TObject);
VAR
file_name_: String;
begin
file_name_ := 'D:\test.wma';
mciOpenParms.lpstrDeviceType:='''';
mciOpenParms.lpstrElementName := PChar(file_name_);
mciSendCommand(0,MCI_OPEN,MCI_OPEN_ELEMENT,DWORD(@mciOpenParms));
m_MCIDeviceID := mciOpenParms.wDeviceID;
mciPlayParms.dwCallback := Handle;
mciPlayParms.dwFrom := 29*1000;
mciPlayParms.dwTo := mciPlayParms.dwFrom+1500;
end;

//开始播放
procedure TForm1.Button2Click(Sender: TObject);
begin
mciSendCommand(m_MCIDeviceID,MCI_PLAY,MCI_FROM or MCI_TO or MCI_NOTIFY,integer(@mciPlayParms));
end;

//如何获取到当前播放时间点
/*
windows sdk 说明

The MCI_PLAY_PARMS structure contains positioning information for the MCI_PLAY command.

typedef struct {
DWORD dwCallback;
DWORD dwFrom;
DWORD dwTo;
} MCI_PLAY_PARMS;


Members

dwCallback

The low-order word specifies a window handle used for the MCI_NOTIFY flag.

dwFrom

Position to play from.

dwTo

Position to play to.

Remarks

When assigning data to the members of this structure, set the corresponding flags in the fdwCommand parameter of the mciSendCommand function to validate the members.
*/

end.


[解决办法]
一个WAV文件播放所发生的事件序列为：(1)命令播放WAV文件并立即返回；(2)播放WAV文 件；(3)完成后发送通知消息MM_MCINOTIFY。

所以你加入如下代码：
private
{ Private declarations }
procedure MCINotify(Var Msg:TMessage);Message MM_MCINOTIFY;

procedure TForm1.MCINotify(Var Msg:TMessage);
begin
showmessage('播放完毕！');
end;
[解决办法]
上面这个不太准确，在你发的另外个帖子里给出了完整的代码，包括获取当前播放位置！