我怎样才能将这两行重构为一个陈述？

Question

I have the following code:

// TryGetAttributeValue returns string value or null if attribute not found
var attribute = element.TryGetAttributeValue("bgimage");

// Convert attribute to int if not null
if (attribute != null) BgImage = convert.ToInt32(attribute);

The thing I don't like is that I have to create a temp variable, attribute , in order to test if it's null or not, and then assign the value to the BgImage variable, which is a nullable int .

I was hoping I could figure out a way to write it all on one line, but I cannot figure a way. I even tried using a ternary statement, but got nowhere:

if (element.TryGetAttributeValue("bgimage") != null) ? BgImage = //Convert result to int :  else null; 

Realistically, my original two lines of code do the job. I was just hoping to pare it down to one line. But, if anyone knows how to do what I'm trying to accomplish, I'd love to learn how.

Answer 1

I recommend you to use Linq to Xml for parsing Xml (according to your attempt you have BgImage as nullable integer):

BgImage = (int?)element.Attribute("bgimage");

You also can assign some default value if BgImage is not nullable:

BgImage = (int?)element.Attribute("bgimage") ?? 0;

Answer 2

Assuming TryGetAttributeValue returns a string you could do something like

BgImage = convert.ToInt32(element.TryGetAttributeValue("bgimage") ?? "-1")

This would set BgImage to a default value ( -1 ) if the attribute does not exist. If you would prefer to have BgImage set to null when there is no bgimage attribute then it gets a little bit clunkier

BgImage = element.TryGetAttributeValue("bgimage") != null ? 
    convert.ToInt32(element.TryGetAttributeValue("bgimage")) : (int?)null;