Anonymous type properties are read only and they cannot be set. Anonymous types provide a convenient way to encapsulate a set of read-only properties into a single object without having to explicitly define a type first. The type name is generated by the compiler and is not available at the source code level. The type … Read more
You have to use a typed null: (List<Plane>)null Or (Plane[])null Otherwise the compiler has no idea what type you want the anonymous type’s member to be. Update As @AakashM has rightly pointed out – this solves your problem of assigning a null to an anonymous member – but doesn’t actually compile – and if it … Read more
You can create an empty list for anonymous types and then use it, enjoying full intellisense and compile-time checks: var list = Enumerable.Empty<object>() .Select(r => new {A = 0, B = 0}) // prototype of anonymous type .ToList(); list.Add(new { A = 4, B = 5 }); // adding actual values Console.Write(list[0].A);
Update 2019-07-31: CreateMissingTypeMaps is now deprecated in AutoMapper v8, and will be removed in v9. Support for automatically created maps will be removed in version 9.0. You will need to explicitly configure maps, manually or using reflection. Also consider attribute mapping. Update 2016-05-11: DynamicMap is now obsolete. Now you need to create a mapper from … Read more
You can’t declare such a dictionary type directly (there are kludges but these are for entertainment and novelty purposes only), but if your data is coming from an IEnumerable or IQueryable source, you can get one using the LINQ ToDictionary() operator and projecting out the required key and (anonymously typed) value from the sequence elements: … Read more
So here’s, what I finally came up with (inspired by @BlueMonkMN’s answer): public dynamic Merge(object item1, object item2) { if (item1 == null || item2 == null) return item1 ?? item2 ?? new ExpandoObject(); dynamic expando = new ExpandoObject(); var result = expando as IDictionary<string, object>; foreach (System.Reflection.PropertyInfo fi in item1.GetType().GetProperties()) { result[fi.Name] = fi.GetValue(item1, … Read more
Just a little update to this answer since C# 7 is out in the wild. Tuples have super powers now and can sometimes replace anonymous types and classes. Take for example this method that accepts and returns tuples with named properties. To help illustrate what is possible, the Whatever function transforms the input shape and … Read more
Make the anonymous type into a class… public class Person { public Person() { } public String Name { get; set; } public DateTime DOB { get; set; } } Person p = from person in db.People where person.Id = 1 select new Person { Name = person.Name, DOB = person.DateOfBirth }
Anonymous objects are internal, which means their members are very restricted outside of the assembly that declares them. dynamic respects accessibility, so pretends not to be able to see those members. If the call-site was in the same assembly, I expect it would work. Your reflection code respects the member accessibility, but bypasses the type’s … Read more
You seem to be mixing three completely different, orthogonal things: static vs. dynamic typing manifest vs. implicit typing named vs. anonymous types Those three aspects are completely independent, they have nothing whatsoever to do with each other. Static vs. dynamic typing refers to when the type checking takes place: dynamic typing takes place at runtime, … Read more