Add item to an anonymous list

Question

I have a list of anonymous type

var myList = db.Products.Select(a => new {a.ProductName, a.ProductId, 
a.Priority}).ToList();

And I want to add an other item to this list like

myList.Insert(0, new { "--All--", 0, 0}); //Error: Has some invalid arguments

I also tried

myList.Add(new { "--All--", 0, 0}); //Error: Has some invalid arguments

How can I do that?

Edit:

I did this after first answer

var packageList = db.Products.Select(a => new { 
         a.ProductName, a.ProductId, a.Priority }).ToList();

packageList.Insert(0, new { ProductName = "All", ProductId = 0, Priority = 0 });

but same error again.

Answer 1

You should specify property names of anonymous object you create:

myList.Insert(0, new { ProductName = "--All--", ProductId = 0, Priority = 0});

Keep in mind - you should list all properties of anonymous type (names should be same), they should be used in same order, and they should have exactly same types. Otherwise object of different anonymous type will be created.