VixenModules.Editor.TimedSequenceEditor.MarkManager.decreaseSelectedMarks C# (CSharp) Method

        private void decreaseSelectedMarks()
        {
            int incrementValue = Convert.ToInt32(textBoxTimeIncrement.Text);
            TimeSpan incrementSpan = TimeSpan.FromMilliseconds(incrementValue);
            List<TimeSpan> selectedMarks = new List<TimeSpan>();
            foreach (int itemIndex in listViewMarks.SelectedIndices)
            {
                TimeSpan newTimeSpan = _displayedCollection.Marks[itemIndex].Subtract(incrementSpan);
                if (newTimeSpan.CompareTo(TimeSpan.Zero) < 0)   //Make sure theres never a negative timespan
                {
                    newTimeSpan = TimeSpan.Zero;
                }
                updateMark(itemIndex, newTimeSpan);
                selectedMarks.Add(newTimeSpan);
            }
            selectMarks(selectedMarks);
        }