Indy TIdTCPClient 接收文本

Question

我嘗試在 idtcpclient 中接收文本，但它不起作用。 這是我在計時器中使用的代碼：

procedure TForm1.Timer2Timer(Sender: TObject);
var
  receivedtext:string;
begin
  if idtcpclient1.Connected = true then
  begin
    with idtcpclient1 do
    begin
      if not IOHandler.InputBufferIsEmpty then
      begin
        try
          receivedtext := IOHandler.ReadLn;
        finally
          if receivedtext = '' = false then
          begin
            showmessage(receivedtext);
            idtcpclient1.IOHandler.InputBuffer.Clear;
            receivedtext := '';
          end;
        end;
      end;
    end;
  end
  else
  begin
    timer2.Enabled := false;
  end;
end;

定時器的間隔為 8 毫秒。 計時器在連接時自動啟用。 但是當我發送一些東西時，我沒有收到消息框或錯誤。 我確信我寫了數據，因為當我使用tclientsocket我確實收到了它。

我做錯了什么？

Answer 1

使用更像這樣的東西：

procedure TForm1.Timer2Timer(Sender: TObject);
var
  receivedtext: string;
begin
  with IdTCPClient1 do
  begin
    try
      if IOHandler.InputBufferIsEmpty then
      begin
        IOHandler.CheckForDataOnSource(0);
        IOHandler.CheckForDisconnect;
        if IOHandler.InputBufferIsEmpty then Exit;
      end;
      receivedtext := IOHandler.ReadLn;
    except
      Timer2.Enabled := False;
      Exit;
    end;
    if receivedtext <> '' then
      ShowMessage(receivedtext);
  end;
end;

話雖如此，這種代碼最好使用工作線程而不是計時器來實現。

1 - 創建一個從TThread派生的新類（文件 > 新建 > 其他 > 線程對象）

type
  TDataEvent = procedure(const Data: string) of object;

  TReadingThread = class(TThread)
  private
    FClient: TIdTCPClient;
    FData: string;
    FOnData: TDataEvent;
    procedure DataReceived;
  protected
    procedure Execute; override;
  public
    constructor Create(AClient: TIdTCPClient); reintroduce;
    property OnData: TDataEvent read FOnData write FOnData;
  end;

constructor TReadingThread.Create(AClient: TIdTCPClient);
begin
  inherited Create(True);
  FClient := AClient;
end;

procedure TReadingThread.Execute;
begin
  while not Terminated do
  begin
    FData := FClient.IOHandler.ReadLn;
    if (FData <> '') and Assigned(FOnData) then
      Synchronize(DataReceived);
  end;
end;

procedure TReadingThread.DataReceived;
begin
  if Assigned(FOnData) then
    FOnData(FData);
end;

2 - 修改您的連接代碼：

IdTCPClient1.Connect;
try
  Thread := TReadingThread.Create(IdTCPClient1);
  Thread.OnData := DataReceived;
  Thread.Resume;
except
  IdTCPClient1.Disconnect;
  raise;
end;

...

if Assigned(Thread) then Thread.Terminate;
try
  IdTCPClient1.Disconnect;
finally
  if Assigned(Thread) then
  begin
    Thread.WaitFor;
    FreeAndNil(Thread);
  end;
end;

...

procedure TForm1.DataReceived(const Data: string);
begin
  ShowMessage(Data);
end;