delphi 线程的使用

unit untWorkThread;



interface



uses

  Windows,Classes,SysUtils;



type

  TWorkItem=class

  end;

  TProcessWork=procedure (Sender:TObject;Work:TWorkItem) of Object;

  TWorkThread=class(TThread)

  private

    FCriticalSection:TRTLCriticalSection;

    hEvent:Cardinal;

    FList:TList;

    FProcessWork:TProcessWork;

    procedure ProcessWork(Work:TWorkItem);

    function GetWork(var AWork:TWorkItem):Boolean;

  protected

    procedure Execute;override;

  public

    procedure AddWork(AWork:TWorkItem);

    constructor Create;

    destructor Destroy; override;

    property OnProcessWork:TProcessWork read FProcessWork write FProcessWork;

  end;



implementation



{TWorkThread}



constructor TWorkThread.Create;

begin

  InitializeCriticalSection(FCriticalSection);

  hEvent:=CreateEvent(nil,False,False,nil);

  FList:=TList.Create;

  Self.FreeOnTerminate:=False;

  inherited Create(False);

end;



destructor TWorkThread.Destroy;

var

  i:Integer;

begin

  for i:=FList.Count-1 downto 0 do TWorkItem(FList.Items[i]).Free;

  DeleteCriticalSection(FCriticalSection);

  FList.Free;

  CloseHandle(hEvent);

end;



function TWorkThread.GetWork(var AWork:TWorkItem):Boolean;

begin

  Result:=False;

  EnterCriticalSection(FCriticalSection);

  try

    if FList.Count>0 then

    begin

      AWork:=TWorkItem(FList.Items[0]);

      FList.Delete(0);

      Result:=True;

    end;

  finally

    LeaveCriticalSection(FCriticalSection);

  end;

end;



procedure TWorkThread.Execute;

var

  Work:TWorkItem;

begin

  while not Self.Terminated do

  begin

    WaitForSingleObject(hEvent,INFINITE);

    while GetWork(Work) do

    begin

      ProcessWork(Work);

      Work.Free;

    end;

  end;

end;



procedure TWorkThread.ProcessWork(Work:TWorkItem);

begin

  if Assigned(FProcessWork) then FProcessWork(Self,Work);

end;



procedure TWorkThread.AddWork(AWork:TWorkItem);

begin

  EnterCriticalSection(FCriticalSection);

  try

    FList.Add(AWork);

  finally

    LeaveCriticalSection(FCriticalSection);

  end;

  SetEvent(hEvent);

end;



end.