动态生成TMediaPlayer控件的问题(50分)

我的主窗口中动态生成了一个TMediaPlayer的对象,在线程中调用这个对象播放音乐,为什么动态生成的就会影响程序主界面移动一次后即被锁定,而静态生成的TMediaPlayer对象,则不会影起主窗口的锁屏呢?
程序代码如下:
TForm1 = class;

TChThread = class(TThread)
private
EventHandle: THandle;
FForm: TForm1;
procedure Action;
protected
procedure Execute;override;
public
constructor Create(form: TForm1);
destructor Destroy;override;
end;


TForm1 = class(TForm)
Label1: TLabel;
Button2: TButton;

Label2: TLabel;
procedure FormCreate(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure FormClose(Sender: TObject;
var Action: TCloseAction);
private
{ Private declarations }
Thread: TChThread;
FSpeed: Integer;
FStopAction: Boolean;

public
{ Public declarations }
Mediaplayer1: TMediaPlayer;
proceduredo
It(Labe: TLabel;
p: string);
end;


var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin

FStopAction:= False;
FSpeed:= 20;

MediaPlayer1:= TMediaPlayer.Create(Self);
Mediaplayer1.Parent:= Self;
//此句注释后就不会有问题了.或者静态生成的控件也不会有问题
//MediaPlayer1.Visible:= False;

Thread:= TChThread.Create(Self);
end;


procedure TForm1.Button2Click(Sender: TObject);
begin

SetEvent(Thread.EventHandle);
end;


{ TChThread }

procedure TChThread.Action;
begin

FForm.DoIt(FForm.Label1, 'C:/Program Files/Tencent/QQ/sound/call.wav' );
FForm.DoIt(FForm.Label2, 'C:/Program Files/Tencent/QQ/sound/msg.wav' );
end;


constructor TChThread.Create(form: TForm1);
begin

FForm:= form;
FreeOnTerminate:= True;

EventHandle:= CreateEvent(nil, True, False, 'Kevin.J.Hoo');

inherited Create(False);
end;


destructor TChThread.Destroy;
begin

CloseHandle(EventHandle);


Terminate;
inherited;
end;


procedure TChThread.Execute;
begin

while not Terminateddo

begin

WaitForSingleObject(EventHandle, INFINITE);
ResetEvent(EventHandle);

if not FForm.FStopAction then

Action;
if Terminated then

Break;

end;


end;


procedure TForm1.DoIt(Labe: TLabel;
P: string);
var
i, Height, Width: Integer;
rRect: TRect;
begin

MediaPlayer1.FileName:= p;
MediaPlayer1.Open;

MediaPlayer1.Play;
with Labedo

begin

Height:= Canvas.TextHeight(Caption);
Width:= Canvas.TextWidth(Trim(Caption));
//此处Width在字体变斜后,会不正确,有待改进
for i:= 0 to Widthdo

if not FStopAction then

begin

Canvas.Lock;
Canvas.Brush.Style:= bsClear;
Canvas.Font.Color:= clBlue;
rRect:= Rect(0, 0, i, Height);
Sleep(FSpeed);
Canvas.TextRect(rRect, 0, 0, Caption);

Canvas.Unlock;
end
else

Break;

end;

end;


procedure TForm1.FormClose(Sender: TObject;
var Action: TCloseAction);
begin

Thread.Terminate;
FStopAction:= True;
end;

没有人顶,自己顶下