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unit Thread2;

 
interface  

 
uses Windows, SysUtils, Classes, IdHTTP, IdComponent, SyncObjs;  

 
type  
  TThreadWorkEvent = procedure(Sender: TThread; AWorkMode: TWorkMode; const AWorkCount: Integer)  
   of object;  
  TWorkBeginEvent = procedure(Sender: TObject; AWorkMode: TWorkMode;  
   const AWorkCountMax: Integer) of object;  

type  
  DownloadThread = class(TThread)
  private  
    FIdHTTP: TIdHTTP;  
    FWorkEvent: TThreadWorkEvent;  
    FURL: String;  
    FFileName: String;  
    FWorkCountMax: Integer;  
    procedure InternalOnWork(ASender: TObject; AWorkMode: TWorkMode;
      AWorkCount: Integer);
    procedure InternalOnWorkBegin(ASender: TObject; AWorkMode: TWorkMode;
      AWorkCountMax: Integer);
  protected
    procedure Execute; override;  
  public
    constructor Create;  
    destructor Destroy; override;  
    property URL: String read FURL write FURL;  
    property FileName: String read FFileName write FFileName;  
    property WorkCountMax: Integer read FWorkCountMax;  
    property OnWork: TThreadWorkEvent read FWorkEvent write FWorkEvent;  
  end;  

 
implementation  

constructor DownloadThread.Create;
begin
  inherited Create(True);  
  FIdHTTP := TIdHTTP.Create(nil);
  FIdHTTP.OnWork := InternalOnWork;
  FIdHTTP.OnWorkBegin := InternalOnWorkBegin;
end;  

destructor DownloadThread.Destroy;
begin
  FIdHTTP.Free;  
  inherited;
end;  

procedure DownloadThread.Execute;
var  
  Handle: THandle;  
  FS: TFileStream;  
begin  
  Handle := FileCreate(FileName);
  if Handle <> INVALID_HANDLE_VALUE then  
  begin  
    FS := TFileStream.Create(Handle);  
    try  
      FIdHTTP.Get(FURL, FS);  
    finally  
      FS.Free;  
    end;  
  end;
end;  

procedure DownloadThread.InternalOnWork(ASender: TObject; AWorkMode: TWorkMode;
      AWorkCount: Integer);
begin
  if Assigned(FWorkEvent) then
    FWorkEvent(Self, AWorkMode, AWorkCount);
end;  

procedure DownloadThread.InternalOnWorkBegin(ASender: TObject; AWorkMode: TWorkMode;
      AWorkCountMax: Integer);
begin  
  FWorkCountMax := AWorkCountMax;
end;  

end.                    

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  Thread2 := DownloadThread.Create;
  with Thread2 do
  begin
    FreeOnTerminate := True;
    OnWork := Self.OnWork;
    URL := 'http://battlefield-basis.de/bf2maps/Kursk.zip';
    FileName := 'test.zip';
    Resume;
  end;                    

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procedure TMainForm.OnWork(Sender: TThread; AWorkMode: TWorkMode; const AWorkCount: Integer);
const
  S_MSG = '%d Bytes von %d Bytes gedownloadet.';
begin
  if Sender = Thread2 then
    Label1.Caption := Format(S_MSG, [AWorkCount, (Sender as DownloadThread).WorkCountMax]);
    Progress2.Max := (Sender as DownloadThread).WorkCountMax;
    Progress2.Position := AWorkCount
end;                    

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  if Sender = Thread2 then
    Synchronize(UpdateGUI);