Introduction to C # extension methods Small example

C # extension Methods Getting Started small case

Definition of extension method:

l must be a static class, static method

< Span style= "" >l first parameter with keyword " this "

code Description: Here's an example of writing a static class, Myextension, an extension method ADD , indicating that all the INT type of numbers will have to call this ADD the ability of the method, the condition is to introduce myextension namespace.

Let's take a look at the usage:

Code Description: What this code does is declare a int type number and assign a value of 7 , and then call ADD method, you will see the following IntelliSense:

you can see that the extension method is marked with a downward-pointing arrow. Then call on it, give it any int, because I used the params keyword, will automatically parse into an int Array, and then use the RLT The variable is received and displayed to see the result:

Example 2:

Write a way to extend the string, you can standardize the English, such as Hello World will be output, Hello World

Using system;using system.collections.generic;using system.linq;using system.text;namespace wpfLab1{public static CLA SS Strextensenclass {public static string Getnormalformat (this string s) {s = Removeextraspa            CE (s);            string[] Words = S.split (");            string ret = "";            foreach (var word in words) {ret + = STRFSTCHRUPR (word) + "";        } return ret;            } public static string Removeextraspace (this string s) {if (s = = NULL | | s.length <= 1)            {return s;            } bool Lastchrisspace = FALSE;            string ret = "";                     foreach (Var chr in s) {if (chr = = ") {if (lastchrisspace)                    {continue;  } else {lastchrisspace = true;                      RET + = CHR;                    }} else {ret + = CHR;                Lastchrisspace = false;        }} return ret;                } private static string Strfstchrupr (string s) {if (s = = NULL | | S.length < 1) {            return s; } String lowerstr = S.tolower ().            Remove (0, 1); String upperstr = Char.ToUpper (S[0]).            ToString ();        Return (Upperstr + lowerstr); }    }}

Use:

Using system;using system.collections.generic;using system.linq;using system.text;using System.Windows;using System.windows.controls;using system.windows.data;using system.windows.documents;using System.Windows.Input;using System.windows.media;using system.windows.media.imaging;using system.windows.navigation;using System.windows.shapes;using wpflab1;namespace wpflab1{    ///<summary>//MainWindow.xaml Interactive logic    // /</summary> public    partial class Mainwindow:window    {public        MainWindow ()        {            InitializeComponent ();        }        private void Btnhello_click (object sender, RoutedEventArgs e)        {            string s = "HEllo world   ,  Hi,   World,   AA dd  DW   wwdd a ";            Lblhello.content = S.getnormalformat ();}}    }

The above is the introduction of C # extension method of the contents of the small case, more relevant content please pay attention to topic.alibabacloud.com (www.php.cn)!

