LINQ 07- Anonymous Types

Anonymous types allows users to create objects without creating classes. In many cases, we may need to store compound related data, but that will be referred in within a particular method. In .net framework 2.0, anonymous types, we have to write a simple classes and properties to achieve this.

Anonymous types works with Automatic Type Inferencing, Auto Implemented properties and Object Initializers

Example

var e = new {
    ID = 10,
    Name = "John",
    Designation = "Software Engineer",
    Age = 25
};

 

C# Compiler implicitly creates a type and uses it.

Notes:

• As the type name is unknown, automatic type inferencing should be used.
• As Automatic type inferencing is the only option to declare anonymous types, it can be used within code blocks only, can not be used as type member
• Anonymous types with same properties with same property types are considered as equal.

Hence

var e = new {
    ID = 10,
    Name = "John",
    Designation = "Software Engineer",
    Age = 25
};

and

var f = new {
    ID = 11,
    Name = "Mike",
    Designation = "Software Engineer",
    Age = 26
};

are considered as same type.

• Arrays with anonymous type elements can be created as

var e = new[]{ new {
    ID = 10,
    Name = "John",
    Designation = "Software Engineer",
    Age = 25
},
new {
    ID = 11,
    Name = "Mike",
    Designation = "Software Engineer",
    Age = 26
}};

• It is not possible to refer property values within declaration. Following statement is WRONG.

var e = new {
    ID = 10,
    FirstName = "John",
    LastName ="Carter",
    FullName = FirstName + " " + LastName,
    Designation = "Software Engineer",
    Age = 25
};