Casting Linq Query to a Structure in .Net

Question

Good Morning,
I have created a structure to be a cut down version of a Class that I already have. I am trying to use a linq query to iterate through the list of MyClass and create a List based on the results (A discinct list based on a few of the properties on MyClass). Something like this...

List<MyStructure> thisList = (from MyClass thisClass in List<MyClass>
                              select thisClass.Property1, thisClass.Property2, thisClass.Property3 Distinct.Cast<MyStructure>()).ToList<MyStructure>();

where MyStructure contains 3 variables of Property1, Property3 and Property3 with the same types.

I am fully aware that the above code wont compile, but that is the sort i am trying to do. Could someone please tell me if this is possible to do?

Thanks

Answer 1

        var List = new List<MyClass> { 
            new MyClass { Property1 = 1, Property2 = 2, Property3 = 3},
            new MyClass { Property1 = 10, Property2 = 20, Property3 = 30},
            new MyClass { Property1 = 1, Property2 = 2, Property3 = 3} };

        // method 1 - anonymous class
        var thisList = (from MyClass thisClass in List
                        select new
                        {
                            thisClass.Property1,
                            thisClass.Property2,
                            thisClass.Property3
                        }).Distinct().ToList();

        // method 2 - anonymous class
        var result = List.Select(x => new { x.Property1, x.Property2, x.Property3 }).Distinct().ToList();



        // method 3 - group (get the first MyClass object from the 'distinct' group)
        var grouped = (from item in List
                      group item by new { item.Property1, item.Property2, item.Property3 } into itemGroup
                      select itemGroup.First()).ToList();

Answer 2

Exactly what you need

It's called Anonymous types.

From the link:

Answer 3

If you want to use your existing MyStructure, you can simply use the following:

  List<MyStructure> thisList = myClassList.Distinct()
    .Select(c => new MyStructure 
                 { 
                   Property1 = c.Property1, 
                   Property2 = c.Property2, 
                   Property3 = c.Property3
                 }).ToList();