c# - 在父任务抛出异常时停止继续任务

Question

我想确保如果在并行循环中抛出预期，则继续任务不会发生

 var parent = tf.StartNew(() =>

    Parallel.ForEach(QuestionsLangConstants.questionLangs.Values, (i, state) =>
          {
             try
               {
                 qrepo.UploadQuestions(QWorkBook.Worksheets[i.QSheet],
                 QWorkBook.Worksheets[i.QTranslationSheet], i, prog);
               }
             catch (Exception ex)
               {

                 context.Dispose();
                 state.Break();
                //make sure the execution fails  
               }
          }));

var finalTast = parent.ContinueWith(i =>
            {
                if (context != null)
                {
                    DialogResult result = 
     MessageBox.Show("Do You Want to Commit the Questions?", "Save to DB",
      MessageBoxButtons.OKCancel, MessageBoxIcon.Question);

                    if (result.Equals(DialogResult.OK))
                    {
                       //Do Stuff here
                    }
                    else
                    {
                        return;
                    }
                }
            });

Answer 1

您需要使用 ContinueWith overload接收 TaskContinuationOptions 并允许执行冒泡

 var parent = tf.StartNew(() =>

    Parallel.ForEach(QuestionsLangConstants.questionLangs.Values, (i, state) =>
          {
             try
               {
                 qrepo.UploadQuestions(QWorkBook.Worksheets[i.QSheet],
                 QWorkBook.Worksheets[i.QTranslationSheet], i, prog);
               }
             catch (Exception ex)
               {

                 context.Dispose();
                 state.Break();
                //make sure the execution fails  
                throw; //<-- This line was added to stop the continuation task.
               }
          }));

var finalTast = parent.ContinueWith(i =>
            {
               //...
            }, TaskContinuationOptions.OnlyOnRanToCompletion);