Delphi写的DLL，OCX中多线程一个同步问题

//解决Delphi编译的DLL,OCX文件中的线程调用 TThread.Synchronize后挂起无法再激活问题
//调用了TThread.Synchronize函数的所有工程请包含此文件
//仅需将此单元包含到工程文件即可

unit Lib.Common.DLLThread;

interface


implementation

uses Classes, Windows, Messages;

type

  { TDLLSystemController }

  TDLLSystemController = class
  private
    FHandle: HWND;
    FPrevWakeMainThread: TNotifyEvent;
    procedure WakeMainThread(Sender: TObject);
    procedure HookSynchronizeWakeup;
    procedure UnhookSynchronizeWakeup;
  protected
    procedure WndProc(var Message: TMessage);
  public
    constructor Create;
    destructor Destroy; override;
  end;

var
  FDLLController:TDLLSystemController;

{ TDLLSystemController }

constructor TDLLSystemController.Create;
begin
  inherited;
  if IsLibrary then
  begin
    FHandle := AllocateHWnd(WndProc);
    HookSynchronizeWakeup;
  end;
end;

destructor TDLLSystemController.Destroy;
begin
  if IsLibrary then
  begin
    DeallocateHWnd(FHandle);
    UnhookSynchronizeWakeup;
  end;
  inherited;
end;

procedure TDLLSystemController.WndProc(var Message: TMessage);
begin
  case Message.Msg of
    WM_NULL: CheckSynchronize;
  else
    Message.Result := DefWindowProc(FHandle, Message.Msg, Message.wParam, Message.lParam);
  end;
end;

procedure TDLLSystemController.WakeMainThread(Sender: TObject);
begin
  PostMessage(FHandle, WM_NULL, 0, 0);
end;

procedure TDLLSystemController.HookSynchronizeWakeup;
begin
  FPrevWakeMainThread := Classes.WakeMainThread;
  Classes.WakeMainThread := WakeMainThread;
end;

procedure TDLLSystemController.UnhookSynchronizeWakeup;
begin
  Classes.WakeMainThread := FPrevWakeMainThread;
end;


initialization
  if IsLibrary then FDLLController := TDLLSystemController.Create
    else FDLLController:=nil;
finalization
  if Assigned(FDLLController) then FDLLController.Free;
end.