c# (连接)流读取异步无限读取 0

本文关键字：读取 异步 无限 连接 | 更新日期: 2023-09-27 18:30:41

给定以下从Stream异步读取的方法（简化）：

private async void WaitForIncomingMessagesAsync()
{
    var responseStream = WebRequest.Create("some url").GetResponse().GetResponseStream(); // onle here in the example
    var buffer = new byte[8192];
    var stringBuilder = new StringBuilder();
    while (IsRunning /*set by other parts of the program*/)
    {
        int receivedDataCount;
        do
        {
            receivedDataCount = await responseStream.ReadAsync(buffer, 0, buffer.Length);
            if (receivedDataCount != 0)
            {
                stringBuilder.Append(Encoding.ASCII.GetString(buffer, 0, receivedDataCount));
            }
        } while (receivedDataCount > 0);
        var receivedDataJson = stringBuilder.ToString();
        Array.Clear(buffer, 0, buffer.Length);
        stringBuilder.Clear();
    }
}

这工作正常，直到我通过流收到第一条"消息"。从那时起，它将不再停留在 await 处，因为它始终读取 0。

流本身必须始终保持开放。

我错过了什么？我是否必须重置流、刷新流或将位置设置回 0？

responseStream.Position = 0;或responseStream.Seek(0, SeekOrigin.Begin)

抛出 NotSupportedException

c# (连接)流读取异步无限读取 0

根据您的代码，我想您希望每次运行外部循环时都读取新消息。如果是这样，则 GetResponse 应位于外部循环内，否则一旦内部循环完成对流的迭代，您将永远不会读取新数据。

private async void WaitForIncomingMessagesAsync()
{
    var buffer = new byte[8192];
    var stringBuilder = new StringBuilder();
    while (IsRunning)
    {
        using (var responseStream = WebRequest.Create("some url").GetResponse().GetResponseStream())
        {
            int receivedDataCount;
            do
            {
                receivedDataCount = await responseStream.ReadAsync(buffer, 0, buffer.Length);
                if (receivedDataCount != 0)
                {
                    stringBuilder.Append(Encoding.ASCII.GetString(buffer, 0, receivedDataCount));
                }
            } while (receivedDataCount > 0);
        }
        var receivedDataJson = stringBuilder.ToString();
        Array.Clear(buffer, 0, buffer.Length);
        stringBuilder.Clear();
    }
}

我还将您的响应流包装成使用 （..） {} 构造，因此您不必担心手动关闭和处置它。

相关文章：