this.AcceptButton = button1的用法：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace Test02
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            this.AcceptButton = button1;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            MessageBox.Show("引发了接受按钮1");
        }

        
    }
}

this.AcceptButton = button1;只是能对选中的按钮进行操作，并不能对未选中的进行操作。