EF Core: Soft delete with shadow properties and query filters

Question

I've created an interface to try to do a soft delete, mixing shadow properties and query filters. But it's not working.

public interface IDeletableEntity {}

And then in my model builder

 builder.Model.GetEntityTypes()
                .Where(entityType => typeof(IDeletableEntity).IsAssignableFrom(entityType.ClrType))
                .ToList()
                .ForEach(entityType =>
                {
                    builder.Entity(entityType.ClrType).Property<Boolean>("IsDeleted");
                    builder.Entity(entityType.ClrType).HasQueryFilter(e => EF.Property<Boolean>(e, "IsDeleted") == false);
                });

But the line with the query filter doesn't compile. The error I got is "cannot convert lambda expression to type 'lambda expression' because it is not a delegate type"

If I do this it's working.

builder.Entity<MyEntity>().HasQueryFilter(m => EF.Property<Boolean>(m, "IsDeleted") == false);

there are any way to do this? It's in order to have an Interface with IDeletableEntity and not have to do it, in every Entity that I want to use a soft delete Entity

Many thanks in advance,

Answer 1

I've found a simple solution for my answer ;-). Thanks anyway Ivan Stoev

The interface is:

public interface IDeletableEntity
{
    bool IsDeleted { get; }
}

And in your model Builder configuration:

builder.Model.GetEntityTypes()
                       .Where(entityType => typeof(IDeletableEntity).IsAssignableFrom(entityType.ClrType))
                       .ToList()
                       .ForEach(entityType =>
                       {
                           builder.Entity(entityType.ClrType)
                           .HasQueryFilter(ConvertFilterExpression<IDeletableEntity>(e => !e.IsDeleted, entityType.ClrType));
                       });

You need to convertfilterExpression

private static LambdaExpression ConvertFilterExpression<TInterface>(
                            Expression<Func<TInterface, bool>> filterExpression,
                            Type entityType)
                {
                    var newParam = Expression.Parameter(entityType);
                    var newBody = ReplacingExpressionVisitor.Replace(filterExpression.Parameters.Single(), newParam, filterExpression.Body);

                    return Expression.Lambda(newBody, newParam);
                }