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Anonymous Types Containing Anonymous Types

It is possible to create an anonymous type that is composed of additional anonymous types. For

example, assume you wish to model a purchase order that consists of a timestamp, a price point,

and the automobile purchased. Here is a new (slightly more sophisticated) anonymous type repre-

senting such an entity:

// Make an anonymous type that is composed of another.

var purchaseItem = new {

TimeBought = DateTime.Now,

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ItemBought = new {Color = "Red", Make = "Saab", CurrentSpeed = 55},

Price = 34.000};

ReflectOverAnonymousType(purchaseItem);

At this point, you should understand the syntax used to define anonymous types, but you may

still be wondering exactly where (and when) to make use of this new language feature. To be blunt,

the use of anonymous type declarations should be used sparingly, typically only when making use

of the LINQ technology set (see Chapter 14). You would never want to abandon the use of strongly

typed classes/structures simply for the sake of doing so, given anonymous types’ numerous limita-

tions, which include the following:

• You don’t control the name of the anonymous type.

• Anonymous types always extend System.Object.

• The fields and properties of an anonymous type are always read-only.

• Anonymous types cannot support events, custom methods, custom operators, or custom

overrides.

• Anonymous types are always implicitly sealed.

• Anonymous types are always created using the default constructor.

However, when programming with the LINQ technology set, you will find that in many cases

this syntax can be very helpful when you wish to quickly model the overall 

shape of an entity rather

than its functionality.