Check for null csharp

If there is a need to represent the possible abscence of a value I prefer the Option type. Unfortunately all NRTs bring to the table are compile-time checks that you are putting your null-guards in :. Thanks Thomas. I had the following piece of code that does a null check within a Ternary Expression:. Empty : attribute. The compiler explained to me that I am trying to do a null check against a non-nullable value type.

By attempting this, I realized the null check was not necessary after confirming the type System. CustomAttributeTypedArgument is a non-nullable struct. Does this seem accurate to you? Point of sharing this is to demonstrate after going through a code base to update null checks, I learned something the code was doing that is not necessary: a null check against a non-nullable value type.

Hey Jamie, yes, your adjustments looks accurate to me. I see a lot of code that does null checks against value types that can not be null. NET development. But I see that his followers have inherited the same traits.

Your email address will not be published. Notify me of follow-up comments by email. Notify me of new posts by email. This site uses Akismet to reduce spam. Learn how your comment data is processed. In the previous blog posts you learned about different C I've seen also Object.

ReferenceEquals obj, null for this purpose. Is it to avoid equality overrides? LucaPiccioni I've used it to prevent value-type-complains when using generics: geekality. I prefer null! Just to extend your answer: whenever you see a NullReferenceException , you'll generally see that the null object is followed by a. Using that as a rule of thumb, it becomes clear that the exception for datalist. Add data can only be about datalist. Comparatively; for datalist. Value , the problem could be either in datalist or data.

Footnote: I had not seen that this was a 7 year necropost. I'm sorry — Flater. Show 1 more comment. I wonder is there an "isn't null"? Wish they'd implement if obj aint null : — Nick Bull. For isn't null there is if obj is object — yatskovsky. OrnKristjansson because! I miss the IsNot operator from VB.

Show 6 more comments. C 6 has monadic null checking : before: if points! FirstOrDefault ; if next! Jowen Jowen 4, 1 1 gold badge 41 41 silver badges 40 40 bronze badges. That's sneaky. I still love coding Add a comment. Your dataList is null as it has not been instantiated, judging by the code you have posted. Pang 8, gold badges 82 82 silver badges bronze badges.

But trying to do. Equals on a null would throw an exception. Should do! What an oversight! I was thinking that the NullReferenceException was from the object..

I'm new to c and I figured there was a special way of checking for null in c! That too, but I saw Ed S. DaveShaw: Thanks for the heads up. I want to avoid a null object being added for later processing though, so I'll still do a check.

Show 2 more comments. WriteLine object. Community Bot 1 1 1 silver badge. Actually I just tried this, and the remark 'The implied advantage is that it ignores any overrides that may be present in data's class, like "operator! Darren Ruane 2, 1 1 gold badge 7 7 silver badges 16 16 bronze badges. Eugene Chybisov Eugene Chybisov 1, 2 2 gold badges 22 22 silver badges 30 30 bronze badges. Your program is crashing because dataList is null as you never initialize it.

Darren Ruane Darren Ruane 2, 1 1 gold badge 7 7 silver badges 16 16 bronze badges. Is that an assumption or a fact? The compiled output in a test app shows that it gets compiled to a simple! But even on debug builds it compiles to ldloc. I'm very surprised and apologies for causing confusion.

If it is compiled to the simpler! EKW because the! I'm not in a position to check right now but I believe the compiled output of the above code will always cast the object to object ensuring to not call any overloaded operators. Ygalbel Ygalbel 4, 21 21 silver badges 30 30 bronze badges. Charles Plager 9 9 silver badges 18 18 bronze badges.

Ali Ali 3, 4 4 gold badges 36 36 silver badges 53 53 bronze badges. I'm not sure I agree. It looks strange to be calling a method on an object to check if it is null. Without knowing it was an extension method you would think it would throw a null reference exception.

Can totally confirm that Jamie is correct - this will not work. I know because I had a hare-brained moment and wrote a similar extension method :P The code always threw a null reference exception, it absolutely will not go into the extension method.

In this article, you will learn what null values are and how to handle null values in C. Today, in this post, we are going to discuss the Nullable type of C. C data types are divided into two categories - first is Value Type, and the other is Reference Type. Today, we will see the use of NULL values with the help of examples. Any type is known as nullable if you can assign a value or null to this variable it means that the type will have no value. In C all reference types like string are of a nullable type, but the other types like int32 are not nullable type.

A nullable type has two members, HasValue Value HasValue is a Boolean type value that can again have two types of values one in True and other is False. If the variable has a non-null value, then it will be set to true. Value is of Boolean type. The variable value contains the data stored in the nullable type.

HasValue Console. WriteLine var. ToString ; else Console. So in this way, the Null values are handled in C. Now we will see one other important term associated with Null types, and that is Null-Collation in the next section of this post.

It is known as the null-coalescing operator that is used to define the default value for nullable reference or value types. In case if the operand is not null then it returns left-hand operand otherwise the right operand is returned by this. It is used to check the null values.