C# Expression to use Guid bookmark

Question

I have a requirement to work through several tables that need to be synchronized/backed up. All of these tables\' classes implement ITrackModifiedDate:

Answer 1

The general approach is to replace the unsupported Guid operators with Guid.CompareTo(Guid) calls, e.g. instead of

guidA > guidB

use

guidA.CompareTo(guidB) > 0

In your case, replace

 var greaterThanMethod = Expression.GreaterThan(propertyExp, target);

with

var compareTo = Expression.Call(propertyExp, "CompareTo", Type.EmptyTypes, target);
var greaterThanMethod = Expression.GreaterThan(compareTo, Expression.Constant(0));

This works for most of the query providers (LINQ to Objects, LINQ To Entities (EF6)). Unfortunately doesn't work with EF Core 2.x which requires a different approach. If that's the case, register the custom GuidFunctions class as explained in the linked answer, and use this instead:

var greaterThanMethod = Expression.Call(
    typeof(GuidFunctions), "IsGreaterThan", Type.EmptyTypes,
    propertyExp, target);