C# 4.0 - Optional Parameters and Named Arguments

This post covers two new language feature being added to C# 4.0 – Optional Parameters & Named Arguments.

 

Optional Parameters

 

·         C# 4.0 now supports using optional parameters with methods, constructors, and indexers (note: VB has supported optional parameters for awhile).

·         Parameters Are Optional When A Default Value Is Specified as part of a declaration. E.g.

 

	public void SendMail(string toAddress, string bodyText, bool ccAdministrator = true, bool isBodyHtml = false) {     // Full implementation here }   Now the call could be made as:   email.SendMail("bob@foo.com", "Hello World"); email.SendMail("bob@foo.com", "Hello World", true, false);

 

Note: But this approach will not let you pass the value for 4^th parameter - isBodyHtml and utilize optional feature for the 3^rd one. Here comes the usage of Named arguments.

 

Named Arguments:

 

·         C# 4.0 also now supports the concept of “named arguments”. 

·         This allows you to explicitly name an argument you are passing to a method – instead of just identifying it by argument position.

 

·         This enables us to call the above method as: Let you pass the value for 4^th parameter - isBodyHtml and utilize optional feature for the 3^rd one

 

email.SendMail("bob@foo.com", "Hello World", isBodyHtml: true);

 

 

Overall, it’s by no means an earth shattering feature that is being added to the language in stand-alone scenarios

 

Reference : Link

 

Hope this helps.

Arun Manglick