private void MergeSort(List <T> inputList, PropertyComparer <T> comparer)
{
int left = 0;
int right = inputList.Count - 1;
InternalMergeSort(inputList, comparer, left, right);
}
void InternalMergeSort(List <T> inputList, PropertyComparer <T> comparer, int left, int right)
{
if (left < right)
{
int mid = (left + right) / 2;
InternalMergeSort(inputList, comparer, left, mid);
InternalMergeSort(inputList, comparer, (mid + 1), right);
MergeSortedList(inputList, comparer, left, mid, right);
}
}
private void MergeSortedList(List <T> inputList, PropertyComparer <T> comparer, int left, int mid, int right)
{
int total_elements = right - left + 1; //BODMAS rule
int right_start = mid + 1;
int temp_location = left;
List <T> tempList = new List <T>();
while ((left <= mid) && right_start <= right)
{
if (comparer.Compare(inputList[left], inputList[right_start]) <= 0)
{
tempList.Add(inputList[left++]);
}
else
{
tempList.Add(inputList[right_start++]);
}
}
if (left > mid)
{
for (int j = right_start; j <= right; j++)
{
tempList.Add(inputList[right_start++]);
}
}
else
{
for (int j = left; j <= mid; j++)
{
tempList.Add(inputList[left++]);
}
}
//Array.Copy(tempArray, 0, inputArray, temp_location, total_elements); // just another way of accomplishing things (in-built copy)
for (int i = 0, j = temp_location; i < total_elements; i++, j++)
{
inputList[j] = tempList[i];
}
}
protected override void ApplySortCore(PropertyDescriptor prop, ListSortDirection direction)
{
OnSortStarted();
List <T> itemsList = (List <T>)Items;
Type propertyType = prop.PropertyType;
if (!comparers.TryGetValue(propertyType, out PropertyComparer <T> comparer))
{
comparer = new PropertyComparer <T>(prop, direction);
comparers.Add(propertyType, comparer);
}
comparer.SetPropertyAndDirection(prop, direction);
MergeSort(itemsList, comparer);
propertyDescriptor = prop;
listSortDirection = direction;
isSorted = true;
OnListChanged(new ListChangedEventArgs(ListChangedType.Reset, -1));
OnSortFinished();
}