C# String.CopyTo()用法及代码示例

C# String.CopyTo() 方法

String.CopyTo() 方法用于将指定数量的字符从字符串的给定索引复制到字符数组中的指定位置。

用法:

    public void CopyTo (int source_index, 
        char[] destination, 
        int destination_index, 
        int count);

参数：

• source_index- 索引到要从哪里复制字符串的字符串
• destination- 要在其中复制字符串部分的目标字符数组
• destination_index- 目标字符数组中的索引
• count- 要在字符数组中复制的字符总数

返回值： void- 它什么都不返回。

例：

    Input:
    string str = "Hello world!";
    char[] arr = { 'I', 'n', 'c', 'l', 'u', 'd', 'H', 'e', 'l', 'p' };
    
    copying "Hello " to arr:
    str.CopyTo(0, arr, 0, 6);

    Output:
    str = Hello world!
    arr = Hello Help

使用 String.CopyTo() 方法将字符从字符串复制到字符数组的 C# 示例

using System;
using System.Text;

namespace Test
{
    class Program
    {
        static void printCharArray(char[] a){
            foreach (char item in a)
            {
                Console.Write(item);
            }
        }

        static void Main(string[] args)
        {
            string str = "Hello world!";
            char[] arr = { 'I', 'n', 'c', 'l', 'u', 'd', 'H', 'e', 'l', 'p' };

            //printing values
            Console.WriteLine("Before CopyTo...");
            Console.WriteLine("str = " + str);
            Console.Write("arr = ");
            printCharArray(arr);
            Console.WriteLine();

            //copying "Hello " to arr
            str.CopyTo(0, arr, 0, 6);

            //printing values
            Console.WriteLine("After CopyTo 1)...");
            Console.WriteLine("str = " + str);
            Console.Write("arr = ");
            printCharArray(arr);
            Console.WriteLine();


            //copying "World! " to arr
            str.CopyTo(6, arr, 0, 6);

            //printing values
            Console.WriteLine("After CopyTo 1)...");
            Console.WriteLine("str = " + str);
            Console.Write("arr = ");
            printCharArray(arr);
            Console.WriteLine();

            //hit ENTER to exit
            Console.ReadLine();
        }
    }
}

输出

Before CopyTo...
str = Hello world!
arr = IncludHelp
After CopyTo 1)...
str = Hello world!
arr = Hello Help
After CopyTo 1)...
str = Hello world!
arr = world!Help

参考：String.CopyTo(Int32, Char[], Int32, Int32) 方法