C#异步预测

Question

我正忙着在Windows窗体上开发一个股票跟踪应用程序。为了优化我的代码，我决定重写使所有内容都保持最新的主函数。我认为选择正确的行并从正确的行中工作将更容易，而不是为正确的控件设置所有的控件。问题是:它一直跳过我想要运行的任务，不再更新它。我尝试了很多我在网上发现的东西，但我无法让它起作用。所以我回到了最简单的原始代码的形式，看看你们是否有一个想法。这一切的实质是：

        public async void KeepUpdatingEverything(List<object> positionInfo, List<string> tickerList)
        {
            foreach (string ticker in tickerList)
            {
                //code that gets the right row
                List<object> priceInfo = await GetStockPrices(ticker));
                //code that updates all the labels
            }
        }

这样做的想法是，当调用KeepUpdating函数时，它会用代码检查列表，获取每个滴答的价格，然后更新所有相关标签。但是我似乎无法让它工作，因为它总是跳过异步调用。有什么想法吗？

当输入第一个代码时，KeepUpdatingEverything只被调用一次，之后它只会继续更新代码列表。

        private async void button1_Click(object sender, EventArgs e)
        {
            string ticker;
            using (Prompt prompt = new Prompt("Enter the ticker symbol", "Add ticker"))
            {
                ticker = prompt.Result;
                ticker = ticker.ToUpper();
                if (!string.IsNullOrEmpty(ticker))
                {

                    using (Prompt prompt2 = new Prompt("Enter your volume", "Add ticker"))
                    {
                        if (Int32.TryParse(prompt2.Result, out int volume) == true)
                        {
                            using (Prompt prompt3 = new Prompt("Enter your buy price", "Add ticker"))
                            {
                                if (Double.TryParse(prompt3.Result, out double buyPrice) == true)
                                {
                                    try
                                    {
                                        List<object> priceInfo = await GetStockPrices(ticker);
                                        FillTickerLabel(ticker);

                                        List<object> positionInfo = GetPositionVars(ticker, volume, buyPrice, Convert.ToDouble(priceInfo[1]));
                                        FillPositionLabel(ticker, priceInfo[0].ToString(), positionInfo);

                                        List<object> changeInfo = GetChangeVars(ticker, priceInfo);
                                        FillChangeLabels(ticker, priceInfo[0].ToString(), changeInfo);

                                        List<string> tickerList = new List<string>();
                                        tickerList.Add(ticker);
                                        if (tickerList.Count <= 1)
                                        {
                                            _cancellationToken = new CancellationTokenSource();
                                            _runningTask = StartTimer(() => KeepUpdatingEverything(positionInfo, tickerList), _cancellationToken);

                                        }
                                    }
                                    catch
                                    {
                                        MessageBox.Show("Ticker does not exist, or entered incorrect value somewhere else");
                                    }
                                }
                                else
                                {
                                    MessageBox.Show("You did not enter one of the textboxes correctly");
                                }
                            }
                        }
                        else
                        {
                            MessageBox.Show("You did not enter one of the textboxes correctly");
                        }
                    }
                }
                else
                {
                    MessageBox.Show("You did not enter one of the textboxes correctly");
                }
            }
        }

最后，StartTimer函数：

        private async Task StartTimer(Action action, CancellationTokenSource cancellationTokenSource)
        {
            try
            {
                while (!cancellationTokenSource.IsCancellationRequested)
                {
                    await Task.Delay(5000, cancellationTokenSource.Token);
                    action();
                }
            }
            catch (OperationCanceledException) { }
        }

Answer 1

async void意味着您不返回调用方可以await的任务。

你应该像这样使用async Task

public async Task KeepUpdatingEverything(List<object> positionInfo, List<string> tickerList)