/// <summary>
 /// This method is called by clicking the ok button and add valid input value to InputValueList.
 /// Listbox which is screen fills from input Value List
 /// </summary>
 public void EnterCommandExecute()
 {
     if (FilteredNumber != null)
     {
         InputValueList.Add(FilteredNumber.Value);
     }
     FilteredNumber = null;
 }
        /// <summary>
        /// the input values were summed.
        /// </summary>
        private void FilterBySumInput()
        {
            var sumData = InputValueList.ToList()
                          .Distinct()
                          .Sum();

            _outputValueList = Convert.ToString(sumData);
            NotifyPropertyChanged("OutputValueList");
        }
        /// <summary>
        /// Sorted input values in listbox by decreasing order.Duplicate values were skipped by distinct method
        /// </summary>
        private void FilterByDecreaseOrder()
        {
            var filteredData = InputValueList.ToList()
                               .Distinct()
                               .OrderByDescending(x => x);

            _outputValueList = string.Join(",", filteredData);
            NotifyPropertyChanged("OutputValueList");
        }
        /// <summary>
        /// Filtered even input values Where(x => x % 2 == 0)
        /// </summary>
        private void FilterByEvenInput()
        {
            var evenData = InputValueList.ToList()
                           .Distinct()
                           .Where(x => x % 2 == 0)
                           .OrderBy(t => t);

            _outputValueList = string.Join(",", evenData);
            NotifyPropertyChanged("OutputValueList");
        }