System.ArgumentOutOfRangeException：'StartIndex不能小于零。参数名: startIndex‘错误在try-catch中仍然显示

using System;

class Program
{
    static void Main()
    {
        string str = "Hello, World!";
        int startIndex = -5; // 故意设置为负数以触发错误

        try
        {
            // 检查 startIndex 是否小于零
            if (startIndex < 0)
            {
                throw new ArgumentOutOfRangeException(nameof(startIndex), "StartIndex 不能小于零。");
            }

            string result = str.Substring(startIndex, 5);
            Console.WriteLine(result);
        }
        catch (ArgumentOutOfRangeException ex)
        {
            Console.WriteLine(ex.Message);
        }
    }
}