C#

private async Task<int> SearchForAllNumbers(int num = -1)
       {
           if (num == -1)
               DisplayLoadingMessage(true, GetString(Resource.String.Common_SearchTitle), GetString(Resource.String.Common_SearchMessage));
           dates = DateFunctions.GetSelectedDates(DateFrom, DateTo);

           var list = string.Empty;
           var klirwseis = ", Κληρωσεις: ";
           if (num == -1)
               list = ListTextView.Text;
           else
               list = num.ToString();
           var nums = list.Split(',').Select(Int32.Parse).ToList();
           if (seperateCheckBox.Checked)
           {
               DisplayLoadingMessage(false);
               seperateCheckBox.Checked = false;
               for (int k = 0; k < nums.Count; k++)
               {
                   await SearchForAllNumbers(nums[k]);
               }
               return -1;
           }
           var totalCoutner = 0;
           for (int datesPos = 0; datesPos <= dates.Count; datesPos++)
           {
              ... Do some calculations
               }
               HistoryTextView.Text = "Ημερομηνία: " + dates[datesPos] + ", Λίστα: " + list + ", Κληρώθηκε: " + totalCoutner + " φορές" + HistoryTextView.Text;
               if (showListsCheckBox.Checked)
                   HistoryTextView.Text = klirwseis + HistoryTextView.Text;
           }
           DisplayLoadingMessage(false);
           HistoryTextView.Text = ".\n" + HistoryTextView.Text;
           return totalCoutner;
           return 0;
       }

private async Task SearchFoNumbersAsync()
        {
            ActiveCancellationTokenSource = new CancellationTokenSource();
            DrawResultsTypeEnum searchType = (DrawResultsTypeEnum)ShowResultsSpinnerPosition;

            var task = Task.Run(async () =>
            {
                if (searchType == DrawResultsTypeEnum.AllNumbers)
                    await SearchForAllNumbers();
                else if (searchType == DrawResultsTypeEnum.AnyWinningCombination)
                    await SearchAnyWinningCombination();
                SaveHistory();
            }, ActiveCancellationTokenSource.Token); // Pass same token to Task.Run.

            try
            {
                await task;
            }
            catch (System.OperationCanceledException e)
            {
                Console.WriteLine($"{nameof(System.OperationCanceledException)} thrown with message: {e.Message}");
                DisplayLoadingMessage(false);
            }
            finally
            {
                ActiveCancellationTokenSource.Dispose();
                DisplayLoadingMessage(false);
            }
        }

try
            {
                await task;
            }

SearchForAllNumbers()

SearchAnyWinningCombination()