// Returns the index of the last occurrence of a given value in a range of
// this list. The list is searched backwards, starting at index
// index and upto count elements. The elements of
// the list are compared to the given value using the Object.Equals
// method.
//
// This method uses the Array.LastIndexOf method to perform the
// search.
//
public int LastIndexOf(T item, int index, int count)
{
if ((Count != 0) && (index < 0))
{
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.index, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum);
}
if ((Count != 0) && (count < 0))
{
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.count, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum);
}
#if DEBUG
Contract.Ensures(Contract.Result <int>() >= -1);
Contract.Ensures(((Count == 0) && (Contract.Result <int>() == -1)) || ((Count > 0) && (Contract.Result <int>() <= index)));
Contract.EndContractBlock();
#endif
if (_size == 0)
{ // Special case for empty list
return(-1);
}
if (index >= _size)
{
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.index, ExceptionResource.ArgumentOutOfRange_BiggerThanCollection);
}
if (count > index + 1)
{
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.count, ExceptionResource.ArgumentOutOfRange_BiggerThanCollection);
}
int found = _items.LastIndexOf(item);
if (found < index || found > index + count)
{
return(-1);
}
return(found);
}
