public void RemoveIndexRange(int begin, int end)
{
if (end <= begin)
{
return;
}
int range = end - begin;
Array.Copy(keys, end, keys, begin, Size - end);
Array.Copy(values, end, values, begin, Size - end);
for (int i = 1; i <= range; ++i)
{
keys[Size - i] = 0;
values[Size - i] = null;
}
Size -= range;
}