邮箱的删除邮件和垃圾管理

 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.SqlClient;

namespace Long5
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        //收件箱的Click事件
        private void toolStripButton1_Click_1(object sender, EventArgs e)
        {
            string sql = "select * from Mails where IsDelete=0";
            try
            {
                 SqlCommand command=new SqlCommand(sql,DBHelper.connection);
                 DBHelper.connection.Open();
                 SqlDataReader dataReader=command.ExecuteReader();
                 listView1.Items.Clear();                     //清空收件箱的相同内容，避免重复
                 while (dataReader.Read())
                 {
                    ListViewItem item = new ListViewItem(dataReader["Receiver"].ToString());
                    item.Tag=(int)dataReader["id"];
                    listView1.Items.Add(item);
                    item.SubItems.AddRange(new string[]       //循环读取和数据库中绑定的列的内容
                {
                         dataReader["Acceptor"].ToString(),
                         dataReader["Subject"].ToString(),
                         dataReader["Date"].ToString(),
                }  );
                }
                dataReader.Close();
            }
            catch(Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            finally
            {
                DBHelper.connection.Close();
            }
        }

        //垃圾箱的Click事件
        private void toolStripButton2_Click(object sender, EventArgs e)
        {
            if (listView1.SelectedItems.Count == 0)
            {
                MessageBox.Show("请选中要删除的邮件", "提示");
            }
            else
            {
                DialogResult result = MessageBox.Show("确定要删除吗？", "提示",MessageBoxButtons.YesNo,MessageBoxIcon.Information);
                if (result==DialogResult.Yes)
                {
                    try
                    {
                        //查询数据库中的id列一行的内容
                        string sql = string.Format("select isdelete from Mails where id='{0}'", (int)listView1.SelectedItems[0].Tag);
                        SqlCommand command = new SqlCommand(sql,DBHelper.connection);
                        DBHelper.connection.Open();
                        bool isdelete = (bool)command.ExecuteScalar();
                        if (isdelete == false)
                        {
                            //更新数据库表的删除状态
                            string sql1 = string.Format("update Mails set isdelete=1 where id='{0}'", (int)listView1.SelectedItems[0].Tag);
                            command.CommandText = sql1;          //重新指定sql语句，下同
                            int count = command.ExecuteNonQuery();
                            if (count > 0)
                            {
                                MessageBox.Show("删除成功，邮件存放于垃圾箱", "提示");
                            }
                            else
                            {
                                MessageBox.Show("删除失败", "提示");
                            }
                        }
                        else
                        {
                            string sql1 = string.Format("delete from Mails where id='{0}'", listView1.SelectedItems[0].Tag);
                            command.CommandText = sql1;
                            int count = command.ExecuteNonQuery();
                            if (count > 0)
                            {
                                MessageBox.Show("确定要彻底删除邮件吗？", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                            }
                            else
                            {
                                MessageBox.Show("删除失败", "提示");
                            }
                        }
                    }
                    catch(Exception ex)
                    {
                     MessageBox.Show(ex.Message);
                    }
                    finally
                    {
                        DBHelper.connection.Close();
                    }
                }
            }
        }

        //删除的Click事件
        private void toolStripButton3_Click(object sender, EventArgs e)
        {
            listView1.Items.Clear();
            try
            {
                string sql = string.Format("select * from Mails where isdelete=1");
                SqlCommand command = new SqlCommand(sql,DBHelper.connection);
                DBHelper.connection.Open();
                SqlDataReader dataReader = command.ExecuteReader();
                while(dataReader.Read())
                {
                    ListViewItem listView = new ListViewItem(dataReader["Receiver"].ToString());
                    listView.Tag = (int)dataReader["id"];
                    listView1.Items.Add(listView);
                    listView.SubItems.AddRange(new string[]
                {     
                    dataReader["Acceptor"].ToString(),
                    dataReader["Subject"].ToString(),
                    dataReader["Date"].ToString()
                } );
                }
            }
            catch(Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            finally
            {
                DBHelper.connection.Close();
            }
        }
       
        private void toolStripButton4_Click(object sender, EventArgs e)
        {
            this.Close();
        }
    }
}