Question

我无法将OnUDPRead事件链接到IdUDPServer。

代码如下：

uses
  System.SysUtils, IdUDPServer, IdGlobal, IdSocketHandle, Classes;

var
  udp: TIdUDPServer;
  buffer: TIdBytes;
  myBinding: TIdSocketHandle;

procedure UDPRead (Sender: TObject; AData: TStream; ABinding: TIdSocketHandle);
  var
    bytes_received: integer;
  begin
    bytes_received:= AData.size;
  end;

begin
  myBinding := udp.Bindings.Add;
  myBinding.IP := '0.0.0.0';
  myBinding.Port := 5100;

  udp.OnUDPRead := UDPRead; // Error occurs here
  udp.Active := True;
end.

我收到了错误消息：

 [dcc32 Error] ACUR401_20170802_UDPServer.dpr(16): E2029 ';' expected but 'OF' found
 [dcc32 Error] ACUR401_20170802_UDPServer.dpr(28): E2009 Incompatible types: 'method pointer and regular procedure'

我相信我的困难在于我无法将事件处理程序链接到该过程。

Answer 1

您必须为OnUDPRead属性分配匹配的对象方法。您分配的是常规程序。做这样的事情：

type
  TMyObject = class
  public
    procedure UDPRead(AThread: TIdUDPListenerThread; AData: TIdBytes;
      ABinding: TIdSocketHandle);
  end;

{ TMyObject }

procedure TMyObject.UDPRead(AThread: TIdUDPListenerThread; AData: TIdBytes;
  ABinding: TIdSocketHandle);
var
  Received: Integer;
begin
  Received := Length(AData);
  ...
end;

var
  MyObject: TMyObject;
  MyServer: TIdUDPServer;
  MyBinding: TIdSocketHandle;
begin
  MyServer := TIdUDPServer.Create(nil);
  try
    MyBinding := MyServer.Bindings.Add;
    MyBinding.IP := '0.0.0.0';
    MyBinding.Port := 5100;

    MyObject := TMyObject.Create;
    try
      MyServer.OnUDPRead := MyObject.UDPRead;
      MyServer.Active := True;
    finally
      MyObject.Free;
    end;
  finally
    MyServer.Free;
  end;
end.

如何链接OnUDPRead事件

1 个答案: