C# elegant way to check if a property's property is null

c# nullreferenceexception nullable null-conditional-operator
Jon Kragh picture Jon Kragh · Aug 12, 2010 · Viewed 103.2k times · Source

In C#, say that you want to pull a value off of PropertyC in this example and ObjectA, PropertyA and PropertyB can all be null.

ObjectA.PropertyA.PropertyB.PropertyC

How can I get PropertyC safely with the least amount of code?

Right now I would check:

if(ObjectA != null && ObjectA.PropertyA !=null && ObjectA.PropertyA.PropertyB != null)
{
    // safely pull off the value
    int value = objectA.PropertyA.PropertyB.PropertyC;
}

It would be nice to do something more like this (pseudo-code).

int value = ObjectA.PropertyA.PropertyB ? ObjectA.PropertyA.PropertyB : defaultVal;

Possibly even further collapsed with a null-coalescing operator.

EDIT Originally I said my second example was like js, but I changed it to psuedo-code since it was correctly pointed out that it would not work in js.

Answer

Phillip Ngan picture Phillip Ngan · Nov 7, 2014

In C# 6 you can use the Null Conditional Operator. So the original test will be:

int? value = objectA?.PropertyA?.PropertyB?.PropertyC;

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