Question

I have two lists of type SelectListItem.
I am trying remove the items in a list which exists in another list.
i tried all type of code but in vain please help me
The codes i tried are:

Channels=New List<SelectListItem>();
RequestedChannels=New List<SelectListItem>();
Channels = GetChannelList();
RequestedChannels = GetChannelList(UserID, ControlChannels);

1st case

Channels = Channels.Except(RequestedChannels).ToList();

2nd case

Channels = Channels.Where(item => !RequestedChannels.Contains(item)).ToList();

3rd case

foreach (SelectListItem item in RequestedChannels)
                Channels.Remove(item);

But these cases are not working.
Please help.
Thanks and Regards,
Suraj

Answer 1

You need to override Equals and GetHashCode for the Except and Contains methods to work

To compare custom data types, implement the IEquatable(Of T) generic
interface and provide your own GetHashCode and Equals methods for the
type. The default equality comparer, Default, is used to compare
values of types that implement IEquatable(Of T).

See Enumerable.Except for details