Comparing Generic List?

Question

I am working in vb.net. I have two generic lists of a user defined class - lets call this class students.

I am issuing a call to a database which gives me a dataset which I arrange into a generic list of students. Student will have properties like: firstname, lastname, phone, address, etc.

I then issue a call to a foreign web api that I arrange the data back into another generic list of students - same class.

Now I am trying to compare one for one if there are any differences in the database side from what I get in the call to the web api. Is there an easy way to compare generic list of class like this to another object? I cannot be sure of the order of the items so that makes a direct comparison not possible - but is there an obvious way I am missing other than iterating through the generic list and searching for the match in the other generic list.

Lets call them... DatabaseList and APIList

There are these possibilities:

1. Exists in Database but not API
2. Exists in API but not Database
3. Exists in both but not matching between the two

I would love to end up with three new lists so that I can take appropriate actions. Right now the only way I can pull this off is to iterate through the lists and that seems like a bad idea - there must be a better way.

Answer 1

There is an Enumarable.SequenceEqual method for comparing generic sequences. You would probably need to sort the collections first and you would need to implement IEqualityComparer(Of T) for the items.