C# |将字符串复制到指定索引处的数组中

原文:https://www . geeksforgeeks . org/c-sharp-copy-stringdictionary-to-array-at-the-specific-index/

StringDictionary。CopyTo(Array，Int32) 方法用于将字符串字典值复制到指定索引处的一维数组实例。

语法:

public virtual void CopyTo (Array array, int index);

参数:

  • 数组:是一维数组，是从 StringDictionary 复制的值的目的地。
  • 索引:是数组中开始复制的索引。

异常:

  • ArgumentNullException : 如果密钥为空。
  • argumentoutofrangerexception:如果索引小于数组的下界。
  • ArgumentException : 如果数组是多维的或StringDictionary 中的元素数量大于从索引到数组末尾的可用空间。

下面的程序说明了字符串的使用。复制到(数组，Int32) 方法:

例 1:

// C# code to copy StringDictionary
// to Array at the specified index
using System;
using System.Collections;
using System.Collections.Specialized;

class GFG {

    // Driver code
    public static void Main()
    {

        // Creating a StringDictionary named myDict
        StringDictionary myDict = new StringDictionary();

        // Adding key and value into the StringDictionary
        myDict.Add("A", "Apple");
        myDict.Add("B", "Banana");
        myDict.Add("C", "Cat");
        myDict.Add("D", "Dog");
        myDict.Add("E", "Elephant");

        // Creating an Array named myArr
        DictionaryEntry[] myArr = { new DictionaryEntry(),
                                    new DictionaryEntry(),
                                    new DictionaryEntry(),
                                    new DictionaryEntry(),
                                    new DictionaryEntry() };

        // Copying StringDictionary to
        // Array at the specified index
        myDict.CopyTo(myArr, 0);

        // Displaying key and value pairs in Array myArr
        for (int i = 0; i < myArr.Length; i++) {
            Console.WriteLine(myArr[i].Key + " " + myArr[i].Value);
        }
    }
}

输出:

d Dog
b Banana
c Cat
e Elephant
a Apple

例 2:

// C# code to copy StringDictionary
// to Array at the specified index
using System;
using System.Collections;
using System.Collections.Specialized;

class GFG {

    // Driver code
    public static void Main()
    {

        // Creating a StringDictionary named myDict
        StringDictionary myDict = new StringDictionary();

        // Adding key and value into the StringDictionary
        myDict.Add("A", "Apple");
        myDict.Add("B", "Banana");
        myDict.Add("C", "Cat");
        myDict.Add("D", "Dog");
        myDict.Add("E", "Elephant");

        // Creating an Array named myArr
        DictionaryEntry[] myArr = { new DictionaryEntry(),
                                    new DictionaryEntry(),
                                    new DictionaryEntry() };

        // Copying StringDictionary to
        // Array at the specified index
        // This should raise "ArgumentException" as
        // the number of elements in the StringDictionary
        // is greater than the available space from
        // index to the end of array.
        myDict.CopyTo(myArr, 0);

        // Displaying key and value pairs in Array myArr
        for (int i = 0; i < myArr.Length; i++) {
            Console.WriteLine(myArr[i].Key + " " + myArr[i].Value);
        }
    }
}

运行时错误:

未处理异常: 系统。参数异常:目标数组不够长，无法复制集合中的所有项。检查数组索引和长度。

注:

  • 复制到数组的元素按照枚举器遍历 StringDictionary 的相同顺序进行排序。
  • 这个方法是一个 O(n)运算，其中 n 是 Count。

参考:

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