Build an Expression that instantiates an Anonymous Type

gistfile1.cs

    public void CreateExpression()
    {
        Type argType = typeof (MyClass);
        string propertyName = "Name";

        ParameterExpression paramExpression = Expression.Parameter(argType, "item");

        //Create "item.Name" and "item.GetType()" expressions
        var propertyAccessExpression = Expression.Property(paramExpression, propertyName); 
        var getTypeExpression = Expression.Call(paramExpression, "GetType", Type.EmptyTypes);

        Type anonType = CreateAnonymousType<String, Type>("SelectedProp", "TypeOfProp");

        //"SelectProp = item.name"
        MemberBinding assignment1 = Expression.Bind(anonType.GetField("SelectedProp"), propertyAccessExpression);
        //"TypeOfProp = item.GetType()"
        MemberBinding assignment2 = Expression.Bind(anonType.GetField("TypeOfProp"), getTypeExpression);

        //"new AnonymousType()"
        var creationExpression = Expression.New(anonType.GetConstructor(Type.EmptyTypes));

        //"new AnonymousType() { SelectProp = item.name, TypeOfProp = item.GetType() }"
        var initialization = Expression.MemberInit(creationExpression, assignment1, assignment2);

        //"item => new AnonymousType() { SelectProp = item.name, TypeOfProp = item.GetType() }"
        Expression expression = Expression.Lambda(initialization, paramExpression);
    }

    public static Type CreateAnonymousType<TFieldA, TFieldB>(string fieldNameA, string fieldNameB)
    {
        AssemblyName dynamicAssemblyName = new AssemblyName("TempAssembly");
        AssemblyBuilder dynamicAssembly = AssemblyBuilder.DefineDynamicAssembly(dynamicAssemblyName, AssemblyBuilderAccess.Run);
        ModuleBuilder dynamicModule = dynamicAssembly.DefineDynamicModule("TempAssembly");

        TypeBuilder dynamicAnonymousType = dynamicModule.DefineType("AnonymousType", TypeAttributes.Public);

        dynamicAnonymousType.DefineField(fieldNameA, typeof(TFieldA), FieldAttributes.Public);
        dynamicAnonymousType.DefineField(fieldNameB, typeof(TFieldB), FieldAttributes.Public);

        return dynamicAnonymousType.CreateType();
    }
    
    public class MyClass
    {
        public string Name { get; set; }
    }