Lambda表达式里面？ （如果是快捷方式）运算符

Question

I like short code, so recently I was trying to fit if statement and Linq query with lambda expression in one line.

Is it possible to do something like:

db.Users.First(x => x.UserId == providedId)??x.SomeUsefullField

That should return null if user not found, and value of some field if user does exists.

Is it possible to do without first getting user and than getting field value like this:

var user = db.Users.First(x => x.UserId == providedId);
var fieldValue = user.SomeUsefullField;

Thank you for possible solution and knowledge sharing.

Answer 1

Yes, you can use the null propagation operator:

var userField = db.Users.FirstOrDefault(x => x.UserId == providedId)?.SomeUsefullField;

Important here is to use FirstOrDefault , which will return null when no match is found. Then use ?. to only get the SomeUsefullField property when the expression doesn't return null .