C# 中 Array.AsReadOnly(T[]) 方法
C# 中的 Array.AsReadOnly(T[]) 方法為指定陣列返回一個只讀包裝器,即只讀的 ReadOnlyCollection<T>。
語法
public static System.Collections.ObjectModel.ReadOnlyCollection<T> AsReadOnly<T> (T[] array);
此處,T 是陣列元素的型別,而 array T[] 是基於零的、一維陣列。
接下來,我們來看一個實現 Array.AsReadOnly(T[]) 方法的示例 −
示例
using System; using System.Collections.Generic; public class Demo { public static void Main() { String[] arr = { "John", "Tom", "Katie", "Brad" }; // read-only IList wrapper IList<String> list = Array.AsReadOnly( arr ); // Display the values of the read-only IList. Console.WriteLine( "Initial read-only IList..." ); display( list ); // Let us now change the read-only wrapper try { list[0] = "Kevin"; list[1] = "Bradley"; } catch ( NotSupportedException e ) { Console.WriteLine(e.GetType()); Console.WriteLine(e.Message ); Console.WriteLine(); } Console.WriteLine( "After changing two elements, the IList remains the same since it is read-only..." ); display( list ); } public static void display( IList<String> list ) { for ( int i = 0; i < list.Count; i++ ) { Console.WriteLine(list[i] ); } Console.WriteLine(); } }
輸出
將生成以下輸出 −
Initial read-only IList... John Tom Katie Brad System.NotSupportedException Collection is read-only. After changing two elements, tthe IList remains the same since it is read-only... John Tom Katie Brad
廣告