What does “where T : class, new()” mean?

by

That is a constraint on the generic parameter T. It must be a class (reference type) and must have a public parameter-less default constructor.

That means T can’t be an int, float, double, DateTime or any other struct (value type).

It could be a string, or any other custom reference type, as long as it has a default or parameter-less constructor.

More Related Contents:

  1. C# generic “where constraint” with “any generic type” definition?
  2. How to define generic type limit to primitive types?
  3. Why does a generic type constraint result in a no implicit reference conversion error?
  4. C#’s can’t make `notnull` type nullable
  5. C# generic methods, type parameters in new() constructor constraint
  6. Pass An Instantiated System.Type as a Type Parameter for a Generic Class
  7. List or IList [closed]
  8. Check if a class is derived from a generic class
  9. Testing if object is of generic type in C#
  10. What’s the difference between SortedList and SortedDictionary?
  11. C# Create New T()
  12. What are generics in C#? [closed]
  13. Using the “params” keyword for generic parameters in C#
  14. C# vs Java generics [duplicate]
  15. What is reification?
  16. Cannot implicitly convert type ‘Int’ to ‘T’
  17. Generic List – moving an item within the list
  18. C# Generic Operators
  19. Dynamically Create a generic type for template
  20. Why can’t I assign a List to a List?
  21. Console.WriteLine and generic List
  22. In C#, how to instantiate a passed generic type inside a method?
  23. C# instantiate generic List from reflected Type [duplicate]
  24. Type must be a reference Type Error When Calling Generic Method
  25. Mocking generic methods in Moq without specifying T
  26. C# – Get the item type for a generic list
  27. Cast Object to Generic List
  28. The component does not have a resource identified by the uri
  29. How does Java’s use-site variance compare to C#’s declaration site variance?
  30. Convert DataTable to Generic List in C#

Leave a Comment