C#图片上一张下一张

namespace 照片
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        //获得文件夹中所有图片文件的全路径
        string[] path = Directory.GetFiles(@"C:\Users\yn\Pictures\C#\");
        int i = 0;
        //下一张
        private void button2_Click(object sender, EventArgs e)
        {
            //每点一下，i++，path[i]指向下一张图片
            i++;
            if (i>path.Length-1)
            {
                i = 0;//到最后一张，返回第一张
            }
            pictureBox1.Image = Image.FromFile(path[i]);
        }
        //上一张
        private void button1_Click(object sender, EventArgs e)
        {
            i--;
            if (i<0)
            {
                i = path.Length-1;
            }
            pictureBox1.Image = Image.FromFile(path[i]);
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            //窗体加载时，显示一张图片
            pictureBox1.Image = Image.FromFile(@"C:\Users\yn\Pictures\C#\31113.png");
        }
    }
}