Can a collection be null C#?
It is better to return empty collections rather than null when writing methods. The reason being that any code calling your method then doesn’t need to explicitly handle a special null case. Returning an empty collection makes the null check redundant and results in much cleaner method calling code. In C#, the System.
Is list empty or null C#?
As other answers here have shown, in order to check if the list is empty you need to get the number of elements in the list ( myList. Count ) or use the LINQ method . Any() which will return true if there are any elements in the list.
How do I know if IEnumerable collection is empty?
“check if ienumerable is empty c#” Code Answer
- IEnumerable enumerable = new List();
- if(! enumerable. Any())
- {
- throw new InvalidOperationException();
- }
Does .ANY check for null?
Why doesn’t Any() work on a c# null object When calling Any() on a null object, it throws an ArgumentNullException in C#. If the object is null, there definitely aren’t ‘any’, and it should probably return false. Why does C# behave this way? null and an empty sequence are something different.
Should I return null or empty?
Returning an empty collection is better in most cases. The reason for that is convenience of implementation of the caller, consistent contract, and easier implementation. If a method returns null to indicate empty result, the caller must implement a null checking adapter in addition to enumeration.
Why returning null is bad?
This is a violation of DRY principle. Getting a null value is an ambiguous for caller, because it doesn’t say whether the null is returned due to the bug or due to the fact that the order was not found in the database. Returning null is definitely not a domain-driven design approach.
How do you check if an ArrayList contains null?
ArrayList isEmpty() in Java with example The isEmpty() method of ArrayList in java is used to check if a list is empty or not. It returns true if the list contains no elements otherwise it returns false if the list contains any element. Parameter: It does not accepts any parameter.
Is Empty list in C#?
Check Whether a List Is Empty With the List. Any() Function in C. The List. Any() function can also be used to check whether the list is empty or not in C#.
Is IEnumerable empty?
On IEnumerable or IEnumerable , no. But it really doesn’t make much sense. If a collection is empty and you try to iterate over it using IEnumerable , the call to IEnumerator.
Can IEnumerable be null?
An object collection such as an IEnumerable can contain elements whose value is null. If a source collection is null or contains an element whose value is null , and your query doesn’t handle null values, a NullReferenceException will be thrown when you execute the query.
Can FirstOrDefault return null?
8 Answers. FirstOrDefault returns the default value of a type if no item matches the predicate. For reference types that is null . Thats the reason for the exception.
Is it good practice to return null?
Returning null Creates More Work An ideal function, like an assistant cook, will encapsulate work and produce something useful. A function that returns a null reference achieves neither goal. Returning null is like throwing a time bomb into the software. Other code must a guard against null with if and else statements.