LINQ to SQL ,直接在datagridview中修改，结合使用submitchange()

思路是：

直接将IQueryable<T>绑定到BindingSource
再把BindingSource绑定到DataGridView
这样就可以直接用DataContext.SubmitChanges()来向数据库提交更改

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

namespace _18
{
    public partial class Form1 : Form
    {
        booksDataClassesDataContext bookstore = new booksDataClassesDataContext();

        public Form1()
        {

            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            this.book_infoDataGridView.DataSource = this.bookstore.book_info;
            BindingSource bds = new BindingSource();
            bds.DataSource = this.bookstore.book_info;
            this.book_infoBindingSource = bds;
            this.book_infobindingNavigator.BindingSource = bds;

        }



        private void save_Click(object sender, EventArgs e)
        {
            //this.book_infoBindingSource.EndEdit();
            this.book_infoDataGridView.EndEdit();
            var bookquery = from booked in bookstore.book_info
                            select booked;
            ////将泛型集合IQueryable<T>的 bookquery对象集赋给DataGridView
            this.book_infoDataGridView.DataSource = bookquery;

            bookstore.SubmitChanges();
        }
    }
}