线程池如何传递参数

Question

我从CodeGear的实例里整理出一个类：unit ThreadPoolUnit;interface
uses
  Windows,  SysUtils,  Classes;
type
  TObjectHelper = class helper for TObject
end;  TThreadPool = class
  private
    type
      TUserWorkItem = class
        FSender: TObject;
        FWorkerEvent: TNotifyEvent;
      end;
    class procedure QueueWorkItem(Sender: TObject; WorkerEvent: TNotifyEvent; Flags: ULONG); overload; static;
  public
    class procedure QueueWorkItem(Sender: TObject; WorkerEvent: TNotifyEvent); overload; static;
    class procedure QueueIOWorkItem(Sender: TObject; WorkerEvent: TNotifyEvent); static;
    class procedure QueueUIWorkItem(Sender: TObject; WorkerEvent: TNotifyEvent); static;
  end;implementation
const
  WT_EXECUTEDEFAULT       = ULONG($00000000);
  WT_EXECUTEINIOTHREAD    = ULONG($00000001);
  WT_EXECUTEINUITHREAD    = ULONG($00000002);
  WT_EXECUTEINWAITTHREAD  = ULONG($00000004);
  WT_EXECUTEONLYONCE      = ULONG($00000008);
  WT_EXECUTEINTIMERTHREAD = ULONG($00000020);
  WT_EXECUTELONGFUNCTION  = ULONG($00000010);
  WT_EXECUTEINPERSISTENTIOTHREAD  = ULONG($00000040);
  WT_EXECUTEINPERSISTENTTHREAD = ULONG($00000080);
  WT_TRANSFER_IMPERSONATION = ULONG($00000100);function QueueUserWorkItem (func: TThreadStartRoutine; Context: Pointer; Flags: ULONG): BOOL; stdcall; external kernel32 name 'QueueUserWorkItem';function InternalThreadFunction(lpThreadParameter: Pointer): Integer; stdcall;
begin
  Result := 0;
  try
    try
      with TThreadPool.TUserWorkItem(lpThreadParameter) do
        if Assigned(FWorkerEvent) then
          FWorkerEvent(FSender);
    finally
      TThreadPool.TUserWorkItem(lpThreadParameter).Free;
    end;
  except  end;
end;{ TThreadPool }class procedure TThreadPool.QueueWorkItem(Sender: TObject; WorkerEvent: TNotifyEvent);
begin
  QueueWorkItem(Sender, WorkerEvent, WT_EXECUTEDEFAULT);
end;class procedure TThreadPool.QueueIOWorkItem(Sender: TObject; WorkerEvent: TNotifyEvent);
begin
  QueueWorkItem(Sender, WorkerEvent, WT_EXECUTEINIOTHREAD);
end;class procedure TThreadPool.QueueUIWorkItem(Sender: TObject; WorkerEvent: TNotifyEvent);
begin
  QueueWorkItem(Sender, WorkerEvent, WT_EXECUTEINUITHREAD);
end;class procedure TThreadPool.QueueWorkItem(Sender: TObject; WorkerEvent: TNotifyEvent; Flags: ULONG);
var
  WorkItem: TUserWorkItem;
begin
  if Assigned(WorkerEvent) then
  begin
    IsMultiThread := True;
    WorkItem := TUserWorkItem.Create;
    try
      WorkItem.FWorkerEvent := WorkerEvent;
      WorkItem.FSender := Sender;
      if not QueueUserWorkItem(InternalThreadFunction, WorkItem, Flags) then
        RaiseLastOSError;
    except
      WorkItem.Free;
      raise;
    end;
 end;
end;
end.请问如何修改可以让线程池传递参数？
如果不可以用全局变量可以么？

Answer 1

可以把你的参数放到一个class当中，作为Sender传递过去，这样子就可以直接在相应的WorkerEvent当中对class的成员做操作。Type
TMyObject = class
  public
    MyParam0: Integer;
    MyParam1: Integer;
    MyResult: Integer;
  class procedure DoWorker(Sender: TObject);
end;class procedure TMyObject.DoWorker(Sender: TObject);
var
  Obj: TMyObject;
begin
  if Not (Sender is TMyObject) then Exit;
  Obj := TMyObject(Sender);  MyResult := MyParam0 + MyParam1;
end;Obj := TMyObject.Create;
Obj.MyParam0 := 100;
Obj.MyParam1 := 99;
TThreadPool.QueueWorkItem(Obj, TMyObject.DoWorker);