1. ASP. NET MVC Introduction to Mastery--new grammar

C # Feature extension methods

Primarily for generic collections and generic classes

The nature of the extension method: Compile-time, directly to Str. Writeself (2015) replaced with stringutil.writeself (STR,2015);
What if you want to add some members to a type?
Extension methods:

 classProgram {Static voidMain (string[] args) {            stringstr ="2015-01-01"; //calling a static methodDateTime Resualt =Str.            Totry (DateTime.Now);            Console.Write (Resualt); Console.Write (Resualt.            GetType ());        Console.readkey (); }    }    /// <summary>    ///extension method Static class/// </summary>     Public Static classConverttotype {/// <summary>        ///extension method Keyword this/// </summary>        /// <param name= "value" >types to be transferred</param>        /// <returns>returns 0 by default</returns>         Public Static intTotry ( This stringvalue) {            inttemp =0; if(!string. IsNullOrEmpty (value)) {Try                {                    int. TryParse (Value, outtemp); }                Catch{Temp=0; }            }            returntemp; }        /// <summary>        ///Data type Conversions/// </summary>        /// <typeparam name= "T" ></typeparam>        /// <param name= "value" ></param>        /// <param name= "DefaultValue" ></param>        /// <returns></returns>         Public StaticT totry<t> ( This Objectvalue, T defaultvalue) {            //1 Determining type of T 2 type of Object//one problem that arises in generic classes and generic methods is how to assign a default value to a parameterized type T when the following conditions are not known in advance://The DEFAULT keyword returns null if T is a reference type, and the value type returns 0,null return System.Nullable (Of T)            ObjectStartvalue =default(T); if(Value! =NULL)            {                //typeof and GetType () differences//typeof for Type//GetType for type instantiation//Test t=new Test () T.gettype () and typeof (T)                Try{Type Converttype=typeof(T); if(Converttype = =typeof(String)) {Startvalue=value.                    ToString (); }                    if(Converttype = =typeof(Int32)) {Startvalue=Convert.ToInt32 (value); }                    if(Converttype = =typeof(DateTime)) {Startvalue=convert.todatetime (value); }                    return(T) Startvalue; }                Catch                {                    returnDefaultValue; }            }            Else            {                returnDefaultValue; }        }    }

1. ASP. NET MVC Introduction to Mastery--new grammar