C# Feature Details

In this post, would like to provide the new features introduced between major version releases of C# as below:

Version 7.0

        Released on: March, 2017         Target Framework: 4.6.2         Visual Studio version: 2017

• Out variable: In this improved version, you can now declare out variables in the argument list of a method call, rather than writing a separate declaration statement above the line and assign an initial value.

  if (int.TryParse(input, out var answer))
          Console.WriteLine(answer);
  else
          Console.WriteLine("Could not parse input");

• Tuples and Deconstruction: Tuples are lightweight data structures that contain multiple fields to represent the data members. The fields aren't validated, and you can't define your own methods. A tuple can be created by assigning a value to each member, and optionally providing semantic names to each of the members of the tuple.

  (string Alpha, string Beta) namedLetters = ("a", "b");
  Console.WriteLine($"{namedLetters.Alpha}, {namedLetters.Beta}");

  In a tuple assignment, you can also specify the names of the fields on the right-hand side of the assignment as below:

  var alphabetStart = (Alpha: "a", Beta: "b");
  Console.WriteLine($"{alphabetStart.Alpha}, {alphabetStart.Beta}");

  There may be times when you want to unpackage the members of a tuple that were returned from a method. You can do that by declaring separate variables for each of the values in the tuple. This unpackaging is called deconstructing the tuple. It looks as below:

  (int max, int min) = Range(numbers);
  Console.WriteLine(max);
  Console.WriteLine(min);

• Pattern matching
• Local functions
• Expanded expression bodied members
• Ref locals and returns
• Discards
• Binary Literals and Digit Separators
• Throw expressions

Version 6.0

        Released on: July, 2015         Target Framework: 4.6         Visual Studio version: 2015

• Static imports
• Exception filters
• Auto-property initializers
• Expression bodied members
• Null propagator
• String Interpolation
• nameof operator
• Index initializers

Version 5.0

        Released on: August, 2012         Target Framework: 4.5         Visual Studio version: 2012 and 2013

• Asynchronous members
• Caller info attributes

Version 4.0

        Released on: April, 2010         Target Framework: 4.0         Visual Studio version: 2010

• Dynamic binding
• Named/optional arguments
• Generic covariant and contravariant

Version 3.0

        Released on: November, 2007         Target Framework: 2.0, 3.0 and 3.5         Visual Studio version: 2008 and 2010

• Auto-implemented properties
• Anonymous types
• Query expressions
• Lambda expressions
• Expression trees
• Extension methods
• Implicitly typed variables
• Partial methods
• Object and collection initializers

Version 2.0

        Released on: November, 2005         Target Framework: 2.0         Visual Studio version: 2005

• Generics
• Partial types
• Anonymous methods
• Nullable types
• Iterators
• Covariance and contravariance

Version 1.0

        Released on: January, 2002         Target Framework: 1.0         Visual Studio version: 2002

• Classes
• Stucts
• Interfaces
• Events
• Properties
• Delegates
• Expressions
• Statements
• Attributes