Tuples in Dotnet 4.0

A tuple is a data structure that has a specific number and sequence of elements. An example of a tuple is a data structure with three elements (known as a 3-tuple or triple) that is used to store an identifier such as a person's name in the first element, a last name in the second element, and the person's age in the third element. The .NET Framework directly supports tuples with one to seven elements. In addition, you can create tuples of eight or more elements by nesting tuple objects in the Rest property of a Tuple<T1, T2, T3, T4, T5, T6, T7, TRest> object.

Tuples are commonly used in four ways:

• To provide easy access to, and manipulation of, a data set.
• To represent a single set of data. For example, a tuple can represent a database record, and its components can represent individual fields of the record.
• To pass multiple values to a method through a single parameter. For example, the Thread.Start(Object) method has a single parameter that lets you supply one value to the method that the thread executes at startup time. If you supply a Tuple<T1, T2, T3> object as the method argument, you can supply the thread’s startup routine with three items of data.
• To return multiple values from a method without using out parameters (in C#) or ByRef parameters (in Visual Basic).

The Tuple class does not itself represent a tuple. Instead, it is a factory class that provides static methods for creating instances of the tuple types that are supported by the .NET Framework. It provides helper methods that you can call to instantiate tuple objects without having to explicitly specify the type of each tuple component.

Let’s see how to use Tuple,

//Creating Tuple using constructor

Tuple<string, string, int> t1 = new Tuple<string, string, int>("Kalpesh","Patolia", 27);

//Creating Tuple using static method

Tuple<string, string, int> t1 = Tuple.Create("Kalpesh", "Patolia", 27);

Console.WriteLine(t1.Item1); // Output - "Kalpesh"

Console.WriteLine(t1.Item2); // Output - "Patolia"

Console.WriteLine(t1.Item3); // Output - 27

Each item in Tuple is statically typed so while using those items don’t need to cast. So instead of using object array and doing boxing and unboxing you can easily use Tuple in that scenario.

For more information refer the MSDN http://msdn.microsoft.com/en-us/library/system.tuple.aspx