Question

我有一个TCP＆＃34; Server＆＃34;，即每20秒发送一次数据。我试图接收这些数据并显示结果。目前，数据显示3次而不是一次。然后再等待20秒，再次显示数据3次。

with Client do
begin

    Connect;

    while True do
    begin
        try
        if IOHandler.CheckForDataOnSource(1000) then
        begin
            WriteLn('Bytes available: ' IntToStr(IOHandler.InputBuffer.Size));
            IOHandler.ReadBytes(buffer, IOHandler.InputBuffer.Size);
        end;
        except
            on e : exception do
                writeln(e.message);
        end;

        if(buffer <> nil) then
        begin
            SetString(msg, PAnsiChar(@buffer[0], length(buffer));
            buffer := nil;
            IOHandler.InputBuffer.Clear;
        end;

        write(msg);
    end;
end;

Answer 1

无论您是否真正读取任何新数据，您都会在每次循环迭代时调用write(msg)。您在将buffer分配给msg后将其重置为零，但在编写后msg未将''重置为msg。因此，每次循环迭代都会写入已经存在的任何with Client do begin Connect; buffer := nil; repeat try if IOHandler.CheckForDataOnSource(1000) then begin WriteLn('Bytes available: ' + IntToStr(IOHandler.InputBuffer.Size)); IOHandler.ReadBytes(buffer, IOHandler.InputBuffer.Size); SetString(msg, PAnsiChar(buffer), Length(buffer)); Write(msg); buffer := nil; end; except on E: Exception do WriteLn(E.Message); end; until not Connected; end;，直到为其分配新值。

请尝试使用此代码：

with Client do
begin
  Connect;
  buffer := nil;
  repeat
    try
      IOHandler.ReadBytes(buffer, -1);
      WriteLn('Bytes read: ' + Length(buffer));
      SetString(msg, PAnsiChar(buffer), Length(buffer));
      Write(msg);
      buffer := nil;
    except
      on E: Exception do
        WriteLn(E.Message);
    end;
  until not Connected;
end;

可以简化为：

with Client do
begin
  Connect;
  repeat
    try
      if IOHandler.CheckForDataOnSource(IdTimeoutDefault) then
      begin
        WriteLn('Bytes available: ' + IntToStr(IOHandler.InputBuffer.Size));
        Write(IOHandler.InputBufferAsString(en8bit));
      end;
    except
      on E: Exception do
        WriteLn(E.Message);
    end;
  until not Connected;
end;

甚至：

{{1}}

Answer 2

我修复了我遇到的问题，将write（msg）移动到if语句中检查缓冲区是否为nil。

with Client do
begin

    Connect;

    while True do
    begin
        try
            if IOHandler.CheckForDataOnSource(1000) then
            begin
                WriteLn('Bytes available: ' IntToStr(IOHandler.InputBuffer.Size));
                IOHandler.ReadBytes(buffer, IOHandler.InputBuffer.Size);
            end;
        except
            on e : exception do
                writeln(e.message);
        end;

        if(buffer <> nil) then
        begin
            SetString(msg, PAnsiChar(@buffer[0], length(buffer));
            buffer := nil;
            IOHandler.InputBuffer.Clear;
            write(msg); {only write out the message when the buffer is not nil}
        end;
    end;
end;

等待Indy10的数据

2 个答案: