C#-How to use empty List as optional parameter

by

Just use the null coalescing operator and an instance of empty List<string>

public void Process(string param1, List<string> param2 = null) 
{
    param2 = param2 ?? new List<string>();

    // or starting with C# 8
    param2 ??= new List<string>();
}

The problem with this is that if “param2” is null and you assign a new reference then it wouldn’t be accessible in the calling context.

More Related Contents:

  1. how to add new method to TextBox Class [closed]
  2. What is the difference between task and thread?
  3. How is Generic Covariance & Contra-variance Implemented in C# 4.0?
  4. What are the true benefits of ExpandoObject?
  5. Parse Math Expression [duplicate]
  6. List thread safety
  7. Contravariance explained
  8. Overloaded method-group argument confuses overload resolution?
  9. Iterating over JSON object in C#
  10. Limit the number of parallel threads in C#
  11. How can I simulate a mouse click at a certain position on the screen?
  12. How to check if a user belongs to an AD group?
  13. Fastest way to Remove Duplicate Value from a list by lambda
  14. C#: Dynamic runtime cast
  15. Why does C# (4.0) not allow co- and contravariance in generic class types?
  16. Adding unknown (at design time) properties to an ExpandoObject
  17. C# operator overload for `+=`?
  18. Dynamically implementing an interface in .NET 4.0 (C#)
  19. Why classes that implement variant interfaces remain invariant?
  20. DataGridView column footer c#.net winforms
  21. Using DataContractSerializer to serialize, but can’t deserialize back
  22. How to get current working directory path c#?
  23. IsAssignableFrom, IsInstanceOfType and the is keyword, what is the difference?
  24. C# Regex to match the word with dot
  25. mapping multiple tables to a single entity class in entity framework
  26. VS 2015 SSIS Script Tasks cannot be debugged
  27. How to get content type of a web address?
  28. How do I translate an expression tree of one type to a different expression type?
  29. Only assignment, call, increment, decrement, await, and new object expressions can be used as a statement
  30. USB Device Connected

Leave a Comment