c# compare two generic values [duplicate]

by

You cannot use operators on generic types (except for foo == null which is special cased) unless you add where T : class to indicate it is a reference type (then foo == bar is legal)

Use EqualityComparer<T>.Default to do it for you. This will not work on types which only supply an operator overload for == without also either:

  • implement IEquatable<T>
  • overrides object.Equals()

In general implementing the == operator and not also doing at least one of these would be a very bad idea anyway so this is not likely to be an issue.

public bool IsDataChanged<T>()
{           
    T value1 = GetValue2;
    T value2 = GetValue1();

    return !EqualityComparer<T>.Default.Equals(value1 , value2);
}

If you do not restrict to IEquatable<T> then the EqualityComparer default fallback may cause boxing when used with value types if they do not implement IEquatable<T> (if you control the types which are being used this may not matter). I am assuming you were using =! for performance though so restricting to the Generic type will avoid accidental boxing via the Object.Equals(object) route.

More Related Contents:

  1. KeyValuePair with generic values [closed]
  2. How do I clone a generic list in C#?
  3. Remove duplicates from a List in C#
  4. How to dynamically create generic C# object using reflection? [duplicate]
  5. Why isn’t there generic variance for classes in C# 4.0?
  6. Generics and casting – cannot cast inherited class to base class
  7. What is the best way to clone/deep copy a .NET generic Dictionary?
  8. Generic TryParse
  9. Generic constraints, where T : struct and where T : class
  10. Nullable type issue with ?: Conditional Operator
  11. How do I implement IEnumerable
  12. What does “where T : class, new()” mean?
  13. Generic All Controls Method
  14. Nullable reference types with generic return type
  15. C# Generics won’t allow Delegate Type Constraints
  16. Generic C# Code and the Plus Operator [duplicate]
  17. Curiously Recurring Template Pattern and generics constraints (C#)
  18. C# Generic Type Inference With Multiple Types
  19. SortedList, SortedDictionary and Dictionary
  20. How do I check if a given value is a generic list?
  21. Declare a generic type instance dynamically [duplicate]
  22. Creating a Math library using Generics in C#
  23. Accessing properties through Generic type parameter
  24. Why doesn’t C# support implied generic types on class constructors?
  25. Why does this generic method require T to have a public, parameterless constructor?
  26. Are static members of a generic class tied to the specific instance?
  27. Generics with Generic Parameters and Abstract class
  28. How to constrain generic type to must have a construtor that takes certain parameters?
  29. How to write this EF Mock setup code as a reusable Generic Boilerplate?
  30. .NET Managing Layers Relationships

Leave a Comment