Resolving null values in C#

Say you have a method which accepts a string parameter. The method may need to handle null values in some way. One strategy is to validate the parameter and throw an exception:

private static string Resolve(string input)
	if (input == null) throw new ArgumentNullException("Input");

Another strategy is to provide some default value with an if-else statement:

private static string Resolve(string input)
	string res;
	if (input == null)
		res = "Empty input string";
		res = input;
	return res;

This can be greatly simplified with the ternary operator:

private static string Resolve(string input)
	string res = input == null ? "Empty input string" : input;
	return res;

An even simpler solution is by using the null-coalescing operator ?? :

private static string Resolve(string input)
	string res = input ?? "Empty input string";
	return res;

This statement is equal to the first if-else solution but it’s a lot more elegant and concise.

You can use this technique with any nullable type of course, not just strings. The ?? operator can even be chained:

private static string Resolve(string input)
	string intermediate = null;
	string res = input ?? intermediate ?? "Empty input string";
	return res;

Here res will be “Empty input string” if both ‘input’ and ‘intermediate’ are null. If ‘input’ is null and ‘intermediate’ is ‘hello world’ then ‘res’ will be ‘hello world’.

View all various C# language feature related posts here.


About Andras Nemes
I'm a .NET/Java developer living and working in Stockholm, Sweden.

One Response to Resolving null values in C#

  1. Pingback: Resolving null values in C# | Dinesh Ram Kali.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


A great site

Elliot Balynn's Blog

A directory of wonderful thoughts

Robin Sedlaczek's Blog

Developer on Microsoft Technologies

HarsH ReaLiTy

A Good Blog is Hard to Find

Softwarearchitektur in der Praxis

Wissenswertes zu Webentwicklung, Domain-Driven Design und Microservices

the software architecture

thoughts, ideas, diagrams,enterprise code, design pattern , solution designs

Technology Talks

on Microsoft technologies, Web, Android and others

Software Engineering

Web development

Disparate Opinions

Various tidbits

chsakell's Blog

Anything around ASP.NET MVC,WEB API, WCF, Entity Framework & AngularJS

Cyber Matters

Bite-size insight on Cyber Security for the not too technical.

Guru N Guns's

OneSolution To dOTnET.

Johnny Zraiby

Measuring programming progress by lines of code is like measuring aircraft building progress by weight.

%d bloggers like this: