// Helper method for sorting an ArrayList. If the comparer is a SortFieldComparer,
// use the cached-value approach to avoid excessive reflection. For other
// comparers, sort the usual way
internal static void SortHelper(ArrayList al, IComparer comparer)
{
SortFieldComparer sfc = comparer as SortFieldComparer;
if (sfc == null)
{
// sort the usual way
al.Sort(comparer);
}
else
{
// Sort with cached values.
// Step 1. Copy the items into a list augmented with slots for
// the cached values.
int n = al.Count;
int nFields = sfc._fields.Length;
CachedValueItem[] list = new CachedValueItem[n];
for (int i = 0; i < n; ++i)
{
list[i].Initialize(al[i], nFields);
}
// Step 2. Sort the augmented list. The SortFieldComparer will
// fill in the slots as necessary to perform its comparisons.
Array.Sort(list, sfc);
// Step 3. Copy the items back into the original list, now in
// sorted order
for (int i = 0; i < n; ++i)
{
al[i] = list[i].OriginalItem;
}
}
}
object GetValueFromCVI(CachedValueItem cvi)
{
object value = cvi[index];
if (value == DependencyProperty.UnsetValue)
{
// first query for this value. Compute it and cache it.
value = cvi[index] = GetValueCore(cvi.OriginalItem);
}
return(value);
}
// Helper method for sorting an ArrayList. If the comparer is a SortFieldComparer,
// use the cached-value approach to avoid excessive reflection. For other
// comparers, sort the usual way
internal static void SortHelper(ArrayList al, IComparer comparer)
{
SortFieldComparer sfc = comparer as SortFieldComparer;
if (sfc == null)
{
// sort the usual way
al.Sort(comparer);
}
else
{
// Sort with cached values.
// Step 1. Copy the items into a list augmented with slots for
// the cached values.
int n = al.Count;
int nFields = sfc._fields.Length;
CachedValueItem[] list = new CachedValueItem[n];
for (int i=0; i<n; ++i)
{
list[i].Initialize(al[i], nFields);
}
// Step 2. Sort the augmented list. The SortFieldComparer will
// fill in the slots as necessary to perform its comparisons.
Array.Sort(list, sfc);
// Step 3. Copy the items back into the original list, now in
// sorted order
for (int i=0; i<n; ++i)
{
al[i] = list[i].OriginalItem;
}
}
}
object GetValueFromCVI(CachedValueItem cvi)
{
object value = cvi[index];
if (value == DependencyProperty.UnsetValue)
{
// first query for this value. Compute it and cache it.
value = cvi[index] = GetValueCore(cvi.OriginalItem);
}
return value;
}