In AutoMapper 8.0 missing ResolveUsing
You don't need to use this expression, you can "Users.Count" and it'll return 0 if the list is empty.
In AutoMapper 8.0 missing ResolveUsing
I also have the same issue and I'm using the following prototype of ResolveUsing
:
void ResolveUsing(Func<TSource, TResult> mappingFunction);
Instead of replacing existing code, I preferred to create an extension method:
using System;
using AutoMapper;
namespace myLibrary.Extensions
{
public static class AutoMapperCompatibilityExtensions
{
// Summary:
// Resolve destination member using a custom value resolver callback. Used instead
// of MapFrom when not simply redirecting a source member This method cannot be
// used in conjunction with LINQ query projection
//
// Parameters:
// resolver:
// Callback function to resolve against source type
public static void ResolveUsing<TSource, TDestination, TMember, TResult>(this IMemberConfigurationExpression<TSource, TDestination, TMember> member, Func<TSource, TResult> resolver) => member.MapFrom((Func<TSource, TDestination, TResult>)((src, dest) => resolver(src)));
}
}
Later, in my code, I simply referred the namespace:
using myLibrary.Extensions;
...
... map.ResolveUsing(s => ...
...
Hope this helps.
Replace ResolveUsing with MapFrom, and add one more input parameter to the lambda (TDestination).
.ForMember(d => d.UsersCount, map => map.MapFrom((s,d) => s.Users?.Count ?? 0))