Question

我尝试将try catch放在Task.WhenAll（任务）周围，但它没有抓到任何东西。在我的一个任务中，我试图通过在空字符串上使用Substring来人为地生成异常。但所有发生的事情都是应用程序崩溃，默认为Application_UnhandledException。

    private async void RunTasks()
    {

        tasks[0] = HttpExtensions.GetMyData("http://www....");

        tasks[1] = HttpExtensions.GetMyData("http://www.....");

        tasks[2] = GeoLocate.OneShotGeoLocate();

        try
        {
            await Task.WhenAll(tasks);
        }
        catch (AggregateException ae)
        {

            App.ViewModel.ErrorMessage = ae.Message;

        }

 }

Answer 1

要从执行任务中获取所有异常，请使用以下命令：

public static class Resize
{
    public static void ResizeImage(string fileName)
    {
        ResizeImage(fileName, 1000, 1000, true);
    }

    public static void ResizeImage(string fileName, int newHeight, int newWidth, bool keepAspectRatio = true)
    {
        string saveto = Path.GetDirectoryName(fileName) + @"\Alternate\" + Path.GetFileName(fileName);
        try
        {
            using (FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read))
            {
                using (Image ImageFromStream = Image.FromStream(fs))
                {
                    var ImageSize = new Size(newHeight, newWidth);
                    if (keepAspectRatio)
                    {
                        int oWidth = ImageFromStream.Width;
                        int oHeight = ImageFromStream.Height;
                        double pWidth = ((double)ImageSize.Width / (double)oWidth);
                        double pHeight = ((double)ImageSize.Height / (double)oWidth);
                        double percent;
                        if (pHeight < pWidth)
                            percent = pHeight;
                        else
                            percent = pWidth;
                        newWidth = (int)(oWidth * percent);
                        newHeight = (int)(oHeight * percent);
                    }
                    else
                    {
                        newWidth = ImageSize.Width;
                        newHeight = ImageSize.Height;
                    }
                    var ResizedImage = new Bitmap(newWidth, newHeight);
                    using (Graphics gfxHandle = Graphics.FromImage(ResizedImage))
                    {
                        gfxHandle.InterpolationMode = InterpolationMode.HighQualityBicubic;
                        gfxHandle.DrawImage(ImageFromStream, 0, 0, newWidth, newHeight);
                        if (!Directory.Exists(Path.GetDirectoryName(saveto))) { Directory.CreateDirectory(Path.GetDirectoryName(saveto)); }
                        ResizedImage.Save(saveto, ImageFormat.Jpeg);
                    }
                    ResizedImage.Dispose();
                    ResizedImage = null;
                }
            }
        }
        catch (Exception ex)
        {
            Debug.WriteLine(string.Format("Exception: {0}", ex.Message));
        }
    }

Answer 2

这要归功于'nakiya'

private async void RunTasks()
{

    tasks[0] = HttpExtensions.GetMyData("http://www....");

    tasks[1] = HttpExtensions.GetMyData("http://www.....");

    tasks[2] = GeoLocate.OneShotGeoLocate();

    try
    {
        await Task.WhenAll(tasks);
    }
    catch (Exception ae)
    {

        App.ViewModel.ErrorMessage = ae.Message;

    }

}

如何在使用Task.WhenAll（）时捕获在Tasks中发生的异常？

2 个答案: