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

namespace ACCESS增删改操作源码
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private OleDbConnection conn;
        private OleDbDataAdapter da;
        private DataSet ds;

        //以下方法用于填充列表框
        private void ListBoxFill()
        {
            if (this.ds.Tables[0].Rows != null) this.ds.Tables[0].Rows.Clear();
            this.listBoxEmployee.DataSource = null;
            this.listBoxEmployee.Items.Clear();
            this.da.Fill(ds, "雇员");
            this.listBoxEmployee.DataSource = ds.Tables["雇员"];
            this.listBoxEmployee.DisplayMember = "姓名";
            this.listBoxEmployee.ValueMember = "雇员ID";
        }

        //加载窗体时执行以下事件处理程序
        private void Form1_Load(object sender, EventArgs e)
        {
            string NorthwindConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=Northwind.mdb;";
            string quueryString = "select 雇员ID,姓氏,名字,姓氏+名字 AS 姓名 from 雇员";
            this.conn = new OleDbConnection(NorthwindConnectionString);
            this.ds = new DataSet();
            this.ds.Tables.Add("雇员");
            this.da = new OleDbDataAdapter(quueryString, conn);
            //对数据适配器设置插入命令,insert 语句中包含的问号表示查询参数
            this.da.InsertCommand = new OleDbCommand("insert into 雇员(姓氏,名字)values(?,?)", conn);
            this.da.InsertCommand.Parameters.AddWithValue("姓氏", "");
            this.da.InsertCommand.Parameters.AddWithValue("名字", "");
            //对数据适配器设置更新命令,update 语句中包含的问号表示查询参数
            this.da.UpdateCommand = new OleDbCommand("update 雇员 set 姓氏=?,名字=? where 雇员ID=?", conn);
            this.da.UpdateCommand.Parameters.AddWithValue("姓氏", "");
            this.da.UpdateCommand.Parameters.AddWithValue("名字", "");
            this.da.UpdateCommand.Parameters.AddWithValue("雇员ID", -1);
            //对数据适配器设置删除命令,delete 语句中包含的问号表示查询参数
            this.da.DeleteCommand = new OleDbCommand("delete * from 雇员 where 雇员ID=?", conn);
            this.da.DeleteCommand.Parameters.AddWithValue("ID", -1);
            //用雇员姓名信息填充列表框
            this.ListBoxFill();
        }

        //当单击"新增"按钮时执行以下事件处理程序
        private void buttonNew_Click(object sender, EventArgs e)
        {
            if (this.textBoxSurName.Text == "" || this.textBoxName.Text == "")
            {
                this.labelMsg.Text = "姓氏和名字不能为空";
                return;
            }
            //通过parameter对象向insert 语句传递参数
            this.da.InsertCommand.Parameters["姓氏"].Value = this.textBoxSurName.Text;
            this.da.InsertCommand.Parameters["名字"].Value = this.textBoxName.Text;
            DataRow dr = this.ds.Tables[0].NewRow();         //在数据表中新增一行
            dr["姓氏"] = this.textBoxSurName.Text;              //为该行的姓氏列设置值
            dr["名字"] = this.textBoxName.Text;              //为该行的名字列设置值
            this.ds.Tables[0].Rows.Add(dr);                  //将该行添加到数据表的行集合中。
            this.da.Update(this.ds, "雇员");                 //将更新保存到数据库表中。
            this.ListBoxFill();                              //再次填充列表框
            this.listBoxEmployee.SelectedIndex = this.listBoxEmployee.Items.Count - 1;
            this.labelMsg.Text = "新纪录添加成功";
            this.textBoxSurName.Text = "";
            this.textBoxName.Text = "";
            this.textBoxSurName.Focus();
        }

        //当单击"更改"按钮时执行一下处理程序
        private void buttonModify_Click_1(object sender, EventArgs e)
        {
            int selectedIndex = this.listBoxEmployee.SelectedIndex;
            //通过 parameter 对象向 update 语句传递参数
            this.da.UpdateCommand.Parameters["雇员ID"].Value = this.listBoxEmployee.SelectedValue;
            this.da.UpdateCommand.Parameters["姓氏"].Value = this.textBoxSurName.Text;
            this.da.UpdateCommand.Parameters["名字"].Value = this.textBoxName.Text;
            //获取当前选择的数据行
            DataRow dr = this.ds.Tables["雇员"].Select("雇员ID=" + this.listBoxEmployee.SelectedValue)[0];
            dr["姓氏"] = this.textBoxSurName.Text;
            dr["名字"] = this.textBoxName.Text;
            this.da.Update(this.ds, "雇员");
            this.ListBoxFill();
            this.listBoxEmployee.SelectedIndex = selectedIndex;
            this.labelMsg.Text = "选定的记录已经被更新";
        }


        //当单击"删除"按钮时执行以下事件处理程序
        private void buttonDelete_Click_1(object sender, EventArgs e)
        {
            //通过parameter 对象向 delete 语句传递参数
            this.da.DeleteCommand.Parameters["ID"].Value = this.listBoxEmployee.SelectedValue;
            //获取要删除的数据行
            DataRow dr = this.ds.Tables[0].Select("雇员ID=" + this.listBoxEmployee.SelectedValue)[0];
            dr.Delete();
            this.da.Update(this.ds, "雇员");
            this.ListBoxFill();
            this.labelMsg.Text = "选定的记录已经被删除";
        }
        //当在列表框中单击一项时执行以下事件处理程序
        private void listBoxEmployee_Click(object sender, EventArgs e)
        {
            DataRow dr = null;
            if (this.listBoxEmployee.SelectedIndex != -1)
            {
                dr = this.ds.Tables[0].Select("雇员ID=" + this.listBoxEmployee.SelectedValue)[0];
                this.textBoxSurName.Text = dr["姓氏"].ToString();
                this.textBoxName.Text = dr["名字"].ToString();
            }

        }
        //当单击 退出 按钮时执行以下事件处理程序
        private void buttonExit_Click_1(object sender, EventArgs e)
        {
            Application.Exit();
        }

    }
}