Both the built-in nullable types (e.g. int?) and any Nullable<T> types that you use have a HasValue property that lets you determine whether a particular nullable object has a value or not.
- HasValue is true if the object has a value of the corresponding type
- HasValue is false if the object has a null value
For example, if you are using a nullable int:
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| int? herAge = null; |
And you later want to see if this variable has a value (of type int), you can do this:
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| if (herAge.HasValue) Console.WriteLine("She is {0} yrs old", herAge); |
HasValue is useful in cases when you want to perform an operation on an object, where the operation is only valid if the object is non-null.