C＃|将HybridDictionary条目复制到阵列实例

HybridDictionary.CopyTo(Array，Int32)方法用于将HybridDictionary条目复制到指定索引处的一维Array实例。

句法：

public void CopyTo (Array array, int index);

参数：

array : The one-dimensional Array that is the destination of the DictionaryEntry objects copied from HybridDictionary. The Array must have zero-based indexing.

index : The zero-based index in array at which copying begins.

例外情况：

• ArgumentNullException：如果数组为null。
• ArgumentOutOfRangeException：如果索引小于零。
• InvalidCastException：如果源HybridDictionary的类型不能自动转换为目标数组的类型。
• ArgumentException：如果array是多维的，或者源HybridDictionary中的元素数大于从arrayIndex到目标数组末尾的可用空间。

下面的程序说明了HybridDictionary.CopyTo(Array，Int32)方法的用法：

范例1：

// C# code to copy the HybridDictionary
// entries to a one-dimensional Array
// instance at the specified index.
using System;
using System.Collections;
using System.Collections.Specialized;
  
class GFG {
  
    // Driver code
    public static void Main()
    {
  
        // Creating a HybridDictionary named myDict
        HybridDictionary myDict = new HybridDictionary();
  
        // Adding key/value pairs in myDict
        myDict.Add("A", "Apple");
        myDict.Add("B", "Banana");
        myDict.Add("C", "Cat");
        myDict.Add("D", "Dog");
        myDict.Add("E", "Elephant");
        myDict.Add("F", "Fish");
  
        // Creating a one-dimensional Array named myArr
        DictionaryEntry[] myArr = new DictionaryEntry[myDict.Count];
  
        // copying the HybridDictionary entries
        // to a one-dimensional Array instance
        // at the specified index
        myDict.CopyTo(myArr, 0);
  
        for (int i = 0; i < myArr.Length; i++)
            Console.WriteLine(myArr[i].Key + " --> " 
                                  + myArr[i].Value);
    }
}

输出：

A --> Apple
B --> Banana
C --> Cat
D --> Dog
E --> Elephant
F --> Fish

范例2：

// C# code to copy the HybridDictionary
// entries to a one-dimensional Array
// instance at the specified index.
using System;
using System.Collections;
using System.Collections.Specialized;
  
class GFG {
  
    // Driver code
    public static void Main()
    {
  
        // Creating a HybridDictionary named myDict
        HybridDictionary myDict = new HybridDictionary();
  
        // Adding key/value pairs in myDict
        myDict.Add("I", "first");
        myDict.Add("II", "second");
        myDict.Add("III", "third");
        myDict.Add("IV", "fourth");
        myDict.Add("V", "fifth");
  
        // Creating a one-dimensional Array named myArr
        DictionaryEntry[] myArr = new DictionaryEntry[myDict.Count];
  
        // copying the HybridDictionary entries
        // to a one-dimensional Array instance
        // at the specified index
        // This should raise "ArgumentOutOfRangeException"
        // as index is less than 0
        myDict.CopyTo(myArr, -2);
  
        for (int i = 0; i < myArr.Length; i++)
            Console.WriteLine(myArr[i].Key + " --> " 
                                  + myArr[i].Value);
    }
}

运行时错误：

Unhandled Exception:
System.ArgumentOutOfRangeException: Index is less than zero.
Parameter name: index

笔记：

• 元素将以枚举器通过HybridDictionary进行迭代的相同顺序复制到Array。
• 要仅复制HybridDictionary中的键，请使用HybridDictionary.Keys.CopyTo 。
• 要仅复制HybridDictionary中的值，请使用HybridDictionary.Values.CopyTo 。
• 此方法是O(n)运算，其中n是Count。

参考：

• https://docs.microsoft.com/zh-cn/dotnet/api/system.collections.specialized.hybriddictionary.copyto?view=netframework-4.7.2