Filter Linq EXCEPT on properties

Question

This may seem silly, but all the examples I've found for using `Except` in linq use two lists or arrays of only strings or integers and filters them based on the matches, for example: ``` var excludes = users.Except(matches); ``` I want to use exclude to keep my code short and simple, but can't seem to find out how to do the following: ``` class AppMeta { public int Id { get; set; } } var excludedAppIds = new List {2, 3, 5, 6}; var unfilteredApps = new List { new AppMeta {Id = 1}, new AppMeta {Id = 2}, new AppMeta {Id = 3}, new AppMeta {Id = 4}, new AppMeta {Id = 5} } ``` How do I get a list of `AppMeta` back that filters on `excludedAppIds`?

Accepted Answer

Try a simple where query

```
var filtered = unfilteredApps.Where(i => !excludedAppIds.Contains(i.Id)); 
```

The except method uses equality, your lists contain objects of different types, so none of the items they contain will be equal!

Filter Linq EXCEPT on properties

Solution

Problem