NullSafeMapFrom extension for AutoMapper

AutoMapperExtensions.cs

public static class AutoMapperExtensions
{
    public static void NullSafeMapFrom<T, TResult>(this IMemberConfigurationExpression<T> opt, Expression<Func<T, TResult>> sourceMemberExpression)
    {
        var sourceMember = sourceMemberExpression.Compile();

        opt.MapFrom(src =>
        {
            try
            {
                return sourceMember(src);
            }
            catch (NullReferenceException)
            {}

            return default(TResult);
        });
    }
}

This'll silently catch any NullReferenceExceptions that might get thrown from null properties in a call chain. Expression is (sadly) necessary to stop Visual Studio from moaning about the exception being unhandled.

Usage:

.ForMember(dest => dest.Target, opt => opt.NullSafeMapFrom(src => src.Something.That.Will.Throw))

Obviously, it should use expression caching in high throughput environments. YMMV.

You know, I've been looking to split out a MapFrom that uses expressions and a ResolveUsing that uses Func, for this very reason. It also lets me "know" the TResult a little easier.

Hi,

Tried to compile your code both in VS2010 for .NET 4.0 and in VS2013 for .NET 4.5.1 - result is the same on line 10:

error CS0834: A lambda expression with a statement body cannot be converted to an expression tree

What I'm doing wrong?