C Sharp/Extension methods
外觀
< C Sharp
擴展方法是C# 3.0引入的特性。允許你寫自己的方法擴展類的方法。但擴展方法不能訪問類的私有或保護的方法、屬性、欄位。
擴展方法必須聲明在靜態類的靜態方法,至少一個參數指出該擴展方法適用的類。
public static class MyExtensions
{
public static string[] ToStringArray<T>(this List<T> list)
{
string[] array = new string[list.Count];
for (int i = 0; i < list.Count; i++)
array[i] = list[i].ToString();
return array;
}
// to be continued...
}
調用該擴展方法:
List<int> list = new List<int>();
list.Add(1);
list.Add(2);
list.Add(3);
string[] strArray = list.ToStringArray(); // strArray will now contain "1", "2" and "3".
using System;
using System.Collections.Generic;
public static class MyExtensions
{
... // continued from above
public static void WriteToConsole(this string str)
{
Console.WriteLine(str);
}
public static string Repeat(this string str, int times)
{
System.Text.StringBuilder sb = new System.Text.StringBuilder();
for (int i = 0; i < times; i++)
sb.Append(str);
return sb.ToString();
}
}
class ExtensionMethodsDemo
{
static void Main()
{
List<int> myList = new List<int>();
for (int i = 1; i <= 10; i++)
myList.Add(i);
string[] myStringArray = myList.ToStringArray();
foreach (string s in myStringArray)
s.Repeat(4).WriteToConsole(); // string is extended by WriteToConsole()
Console.ReadKey();
}
}