Question

我有一种通过TCP连接下载文件的方法，并且我想在控制台上显示下载完成指示器。我当前使用的方法是引发事件以显示进度条并对其进行更新。

我的问题是显示不同步，并且极大地减缓了下载过程。我尝试使用Tasks处理事件，但无法产生良好的结果，因为多个线程会同时更新进度条，而且很混乱。

下载方法：

public void DownloadFile(Stream stream)
{
    if (!stream.CanWrite)
    {
        // The stream can't be written : invalid argument
        throw new ArgumentException();
    }

    // Get the data lenght first
    var dataLength = long.Parse(ReadLine());

    // Send ready flag
    WriteLine("{OK}");

    var buffer = new byte[DEFAULT_BUFFER_SIZE];
    long bytesWritten = 0;
    try
    {
        // Notify that the stream transfert started if the handler has been implemented
        StreamTransfertStartEvent?.Invoke(dataLength);

        int bytesRead;
        while ((bytesRead = binaryReader.Read(buffer, 0, buffer.Length)) > 0)
        {
            stream.Write(buffer, 0, bytesRead);
            bytesWritten += bytesRead;

            // Notify that the stream transfert progress changed if the handler has been implemented
            StreamTransfertProgressEvent?.Invoke(bytesWritten);

            // The file has been totally written
            if (bytesWritten == dataLength)
            {
                break;
            }
        }
    }
    catch (Exception)
    {
        StreamTransfertFailEvent?.Invoke();
        throw new NetworkException();
    }
}

您可以在代码中看到我用来更新进度条的3个事件：

StreamTransfertStartEvent
StreamTransfertProgressEvent
StreamTransfertFailEvent

对于进度条更新代码（仅由StreamTransfertProgressEvent处理程序调用的代码）：

public static void Update(long current)
{
    var newCompletion = (int)((decimal)current / total * 100);

    // Transfert progressed
    if (completion != newCompletion)
    {
        completion = newCompletion;

        if (completion % 2 == 0)
        {
            Console.SetCursorPosition(1, lastLine - 1);
            Console.Write(new string('=', completion / 2 - 1));
            Console.Write('>');
        }

        var leftStart = 52 - total.ToString().Length - 7 - current.ToString().Length;
        Console.SetCursorPosition(leftStart, lastLine);
        Console.Write(current);

        // Transfert finished
        if (completion == 100)
        {
            Console.SetCursorPosition(50, lastLine - 1);
            Console.Write('=');

            End();
        }
    }
}

控制台应用程序进度条很慢

0 个答案: