Updating entity in EF Core application with SQLite gives DbUpdateConcurrencyException

Question

I try to use optimistic concurrency check in EF Core with SQLite. The simplest positive scenario (even without concurrency itself) gives me Microsoft.EntityFrameworkCore.

Answer 1

I have been using Ivan's answer with great success up to this point. When I updating to EntitiyFrameworkCore 3.1, though, I started getting this warning:

The property '{column name}' on entity type '{entity name}' is a collection or enumeration type with a value converter but with no value comparer. Set a value comparer to ensure the collection/enumeration elements are compared correctly.

To address this, I enhanced his solution by adding:

property.SetValueComparer(new ValueComparer(
    (c1, c2) => c1.SequenceEqual(c2),
    c => c.Aggregate(0, (a, v) => HashCode.Combine(a, v.GetHashCode())),
    c => c.ToArray()));

(based off of a response to a GitHub issue)