C# String.CopyTo()用法及代碼示例

C# String.CopyTo() 方法

String.CopyTo() 方法用於將指定數量的字符從字符串的給定索引複製到字符數組中的指定位置。

用法:

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

參數：

• source_index- 索引到要從哪裏複製字符串的字符串
• destination- 要在其中複製字符串部分的目標字符數組
• destination_index- 目標字符數組中的索引
• count- 要在字符數組中複製的字符總數

返回值： void- 它什麽都不返回。

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() 方法將字符從字符串複製到字符數組的 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();
        }
    }
}

輸出

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

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