C # basics-Application of extension methods,

C # basics-Application of extension methods,

Recently I was interested in the extension method. I looked at the information and recorded several methods of the extension method.

I. basic use of the extension method:

Note: 1. Extension methods must be in static classes. 2 extension methods must declare static methods. 3 extension methods cannot call other custom methods.

public static int TryToInt(this string intStr)        {            int number = 0;            int.TryParse(intStr, out number);            return number;        }public static IEnumerable<string> StartsWith(this IEnumerable<string> ie, string startStr)        {            IEnumerable<string> returnIe = null;            if (ie != null)            {                returnIe = ie.Where(x => x.StartsWith(startStr));            }            return returnIe;        }

Ii. Extension Method generics: The above are all types of extension methods written to death, extension methods support generics as well:

public static bool IsBetween<T>(this T value, T low, T high) where T : IComparable<T>        {            return value.CompareTo(low) >= 0 && value.CompareTo(high) < 0;        }

Iii. Delegation of generic methods: the generic method supports delegation, which facilitates data operations. The foreach method of the set is simulated below.

public static void Each<T>(this IEnumerable<T> items, Action<T> action)   {         foreach (T item in items)         {              action(item);         }    }