what is Co-Varient and Contravarient in C#

Question

Sumit Joshi · Answer

// Assignment compatibility. string str = test ; // An object of a more derived type is assigned to an object of a less derived type. object obj = str; // Covariance. IEnumerable string > strings = new List string >(); // An object that is instantiated with a more derived type argument // is assigned to an object instantiated with a less derived type argument. // Assignment compatibility is preserved. IEnumerable object > objects = strings; / / Contravariance. // Assume that the following method is in the class: // static void SetObject(object o) { } Action object > actObject = SetObject; // An object that is instantiated with a less derived type argument // is assigned to an object instantiated with a more derived type argument. // Assignment compatibility is reversed. Action string > actString = actObject;

Siddarth Pathak · Answer

Can you describe more sir

Sumit Joshi · Answer

Dear Siddarth Covariance and Contravariance are polymorphism extension to the arrays delegates and generics. It provides implicit reference conversion for Arrays Delegates and Generic parameter types. Covariance preserves the assignment compatibility and Contravariance opposite the covariance functionality.

Francis · Answer

Please follow the below url for the detailed information: http://www.codeproject.com/Articles/42863/Covariance-and-Contravariance-in-C

Munesh Sharma · Answer

http://www.c-sharpcorner.com/UploadFile/hasansheik/covariance-and-contravariance-in-C-Sharp/