Automapper Ignore All Non Existing Properties

Code Snippet

73. public static IMappingExpression<TSource, TDestination> IgnoreAllNonExisting<TSource, TDestination>
74.                                             (this IMappingExpression<TSource, TDestination> expression)
75.         {
76.             var sourceType = typeof(TSource);
77.             var destinationType = typeof(TDestination);
78.             var existingMaps = Mapper.GetAllTypeMaps().First(x => x.SourceType.Equals(sourceType) && x.DestinationType.Equals(destinationType));
79.             foreach (var property in existingMaps.GetUnmappedPropertyNames())
80.             {
81.                 expression.ForMember(property, opt => opt.Ignore());
82.             }
83.             return expression;
84.         }