Question

Looking for some best-practice guidance. Let’s say I have a line of code like this:

Color color = someOrder.Customer.LastOrder.Product.Color;

where Customer, LastOrder, Product, and Color could be null under normal conditions. I’d like color to be null if any one of the objects in the path is null, however; in order to avoid null reference exceptions, I’d need to check for the null condition for each one of the objects, e.g.

Color color = someOrder == null ||
              someOrder.Customer == null || 
              someOrder.Customer.LastOrder == null ||
              someOrder.Customer.Product == null ? 
              null : someOrder.Customer.LastOrder.Product.Color;

or I could do this

Color color = null;
try {color = someOrder.Customer.LastOrder.Product.Color}
catch (NullReferenceException) {}

The first method clearly works, but it seems a bit more tedious to code and harder to read. The second way is a bit easier but probably not a good idea to use exception handling for this.

Is there another shortcut way of checking for nulls and assigning null to color if necessary? Or any thoughts on how to avoid NullReferenceExceptions when using such nested references?

Answer 1

You are looking for the null-safe dereferencing operator.

Color color = someOrder?.Customer?.LastOrder?.Product?.Color;

Unfortunately C# doesn’t support it. Maybe it will be added later, but there are no plans to do that at the moment.

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