Linq代码问题

Question

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;namespace Linq实现对数据库的操作
{
    public partial class Form1 : Form
    {
        LinqtosqlClassDataContext linq;
        string strCon = "Data Source=.;Initial Catalog=Student;Integrated Security=True";        public Form1()
        {
            InitializeComponent();
        }        #region 查询班级信息
       ///<summary>
       ///查询班级信息
       ///<summary>
       ///<param name="strKey">查询关键字</param>
        private void BindInfo(string strKey)
        {
            linq = new LinqtosqlClassDataContext(strCon);
            if (strKey == "")
            {
                //获取班级信息
                var result = from info in linq.Class_Info
                             select new
                             {
                                 班级编号 = info.class_No,
                                 班级名称 = info.class_Name,
                                 教授 = info.director,
                                 专业 = info.profession
                             };
                dataGridView1.DataSource = result;
            }
            else
            {
                switch (cboxCondition.Text)
                {
                    case "班级编号":
                        //根据班级编号查询员工信息
                        var resultid = from info in linq.Class_Info
                                       where info.class_No.ToString() == strKey
                                       select new
                                       {
                                           班级编号 = info.class_No,
                                           班级名称 = info.class_Name,
                                           教授 = info.director,
                                           专业 = info.profession
                                       };
                        dataGridView1.DataSource = resultid; 
                        break;
                    case "班级名称":
                        //根据班级编号查询员工信息
                        var resultname = from info in linq.Class_Info
                                       where info.class_Name == strKey
                                       select new
                                       {
                                           班级编号 = info.class_No,
                                           班级名称 = info.class_Name,
                                           教授 = info.director,
                                           专业 = info.profession
                                       };
                        dataGridView1.DataSource = resultname;
                        break;
                    case "教授":
                        //根据班级编号查询员工信息
                        var resultdirector = from info in linq.Class_Info
                                       where info.director == strKey
                                       select new
                                       {
                                           班级编号 = info.class_No,
                                           班级名称 = info.class_Name,
                                           教授 = info.director,
                                           专业 = info.profession
                                       };
                        dataGridView1.DataSource = resultdirector;
                        break;
                }
            }
        }        private void btnSelect_Click(object sender, EventArgs e)
        {
            BindInfo(txtkeyword.Text);
        }        private void btnAdd_Click(object sender, EventArgs e)
        {
            linq = new LinqtosqlClassDataContext(strCon);
            Class_Info class1 = new Class_Info();
            class1.class_No =Convert.ToInt32(txtclassno.Text);
            class1.class_Name = txtclassname.Text;
            class1.director = txtdirector.Text;
            class1.profession = txtprofession.Text;
            linq.Class_Info.InsertAllOnSubmit(class1);
            linq.SubmitChanges();
            MessageBox.Show("班级信息添加成功");
            BindInfo("");
        }
       
    }
}
 #endregion 
显示错误
错误 1 无法从用法中推导出方法“System.Data.Linq.Table<Linq实现对数据库的操作.Class_Info>.InsertAllOnSubmit<TSubEntity>(System.Collections.Generic.IEnumerable<TSubEntity>)”的类型实参。请尝试显式指定类型实参。 E:\控制台应用程序\练习\Linq实现对数据库的操作\Linq实现对数据库的操作\Form1.cs 103 13 Linq实现对数据库的操作

Answer 1

Class_Info 使用LinqtosqlClassDataContext 映射文件内的映射的Class_Info类linq.Class_Info.InsertOnSubmit(class1);