Question

I have an object with string properties, for example, a Patient object with weight and height.

But when the property is null, my code fails when I try to use it, as the property is set to null. I’m trying to create a function that checks if the string/property is null, and if so, set the property to "".

I know that I can do this:

if(string.isNullOrEmpty(patient.weight)) patient.weight = "";

But I need the code to be as clean as possible, and I have a lot of properties, so I don’t want to manually check each one. Ideally, I’d like to have a function that can take the string, (without failing even if it is null), and simply return either the value if it’s not null, or a "" if it is null.

Can anyone give me a clue on this?

Answer 1

Personally I would ensure those properties can never be null by writing them like this:

private string _Name = string.Empty;
public string Name
{
    get
    {
        return _Name;
    }
    set
    {
        _Name = value ?? string.Empty;
    }
}

However, what you’re looking for is probably the ?? operator, also known as the null-coalescing operator, as used above, basically, this expression:

x = y ?? z;

means the same as this:

if (y != null)
    x = y;
else
    x = z;

and that’s not entirely true either. In the above example y is evaluated twice, which does not happen with the ?? operator so a better approximation would be this:

var temp = y;
if (temp != null)
    x = temp;
else
    x = z;