Web 组合查询加 分页

使用ADO.NET 数据访问技术制作web端组合查询加分页的功能关键在于查询SQL语句的拼接

以Car 表为例 每页显示3条数据

数据访问类使用查询方法，tsql 查询的连接字符串，查询的参数放到Hashtable中

 public List<Car> Select(string tsql, Hashtable hh)
     {
         List<Car> list = new List<Car>();
         cmd.CommandText = tsql;
         cmd.Parameters.Clear();
         foreach (string k in hh.Keys)
         {
             cmd.Parameters.Add(k, hh[k]);
         }
         conn.Open();
         SqlDataReader dr = cmd.ExecuteReader();
         if (dr.HasRows)
         {
             while (dr.Read())
             {
                 Car c = new Car();
                 c.Code = dr["Code"].ToString();
                 c.Name = dr["Name"].ToString();
                 c.Brand = dr["Brand"].ToString();
                 c.Oil = Convert.ToDecimal(dr["Oil"]);
                 c.Powers = Convert.ToInt32(dr["Powers"]);
                 c.Exhaust = Convert.ToInt16(dr["Exhaust"]);
                 c.Price = Convert.ToDecimal(dr["Price"]);
                 list.Add(c);
             }
         }
         conn.Close();
         return list;
     }

后台代码封装查询连接字符的方法

/// <summary>
    /// 拼接查询分页的SQL语句
    /// </summary>
    /// <param name="pagenumber">显示第几页</param>
    /// <param name="isall">查最大页数的SQL语句</param>
    /// <returns>查询sql语句的字符创</returns>
    public string ReturnTsql(int pagenumber,bool isall)
    {
        hs.Clear();//清空哈希表数据
        int count = ;//文本是否输内容
        string Tsql = "select top " + pagecount + " *from Car";
        if (isall)//true查所有拼接的语句
            Tsql = "select *from Car";
        string tj = "";
        if (!string.IsNullOrEmpty(TextBox_name.Text.Trim()))//文本框有内容
        {
            Tsql += " where Name like @a";
            tj += "where Name like @a";
            hs.Add("@a", "%" + TextBox_name.Text.Trim() + "%");
            count++;
        }
        if (!string.IsNullOrEmpty(TextBox_oil.Text.Trim()))
        {
            if (count == )
            {
                Tsql += " where Oil" + DropDownList_oil.SelectedValue + " @b";
                tj += " where Oil" + DropDownList_oil.SelectedValue + " @b";
            }
            else
            {
                Tsql += " and Oil" + DropDownList_oil.SelectedValue + " @b";
                tj += " and Oil" + DropDownList_oil.SelectedValue + " @b";
            }
            hs.Add("@b", TextBox_oil.Text.Trim());
            count++;
        }
        if (!string.IsNullOrEmpty(TextBox_price.Text.Trim()))
        {
            if (count == )
            {
                Tsql += " where Price" + DropDownList_pri.SelectedValue + " @c";
                tj += " where Price" + DropDownList_pri.SelectedValue + " @c";
            }
            else
            {
                Tsql += " and Price" + DropDownList_pri.SelectedValue + " @c";
                tj += " and Price" + DropDownList_pri.SelectedValue + " @c";
            }
            hs.Add("@c", TextBox_price.Text.Trim());
            count++;
        }
       //最终拼接的TSQL语句
        if (count > )//文本框有输入
        {
            Tsql += " and Code not in(select top " + (pagecount * (pagenumber - )) + " Code from Car " + tj + ")";
        }
        else//没有输入
        {
            Tsql += " where Code not in(select top " + (pagecount * (pagenumber - )) + " Code from Car " + tj + ")";
        }
        return Tsql;
    }
    //查询最大页数
    public int Maxpage(string tsql,Hashtable has)
    {
        List<Car> clist = new CarData().Select(tsql, has);
        return Convert.ToInt32(Math.Ceiling(clist.Count / (pagecount * 1.0)));
    }

功能代码 （查询 首页 下一页）

 int pagecount = ;//每页显示的数据
     Hashtable hs = new Hashtable();//实例化一个全局的哈希表集合
     protected void Page_Load(object sender, EventArgs e)
     {
         if (!IsPostBack)//加载页面数据绑定
         {
             Repeater1.DataSource = new CarData().Select(ReturnTsql(,false), hs);
             Repeater1.DataBind();
             Label_now.Text = "";//当前页数
             Label_max.Text = Maxpage(ReturnTsql(,true), hs).ToString();//最大页数
             DropDownList_jump.Items.Clear();//跳转页下拉列表数据绑定
             for (int i = ; i <= Maxpage(ReturnTsql(, true), hs); i++)
             {

                 DropDownList_jump.Items.Add(new ListItem(i.ToString(),i.ToString()));
             }
         }
         Button_sel.Click += Button_sel_Click;//查询
         LinkButton_frist.Click += LinkButton_frist_Click;//首页
         LinkButton_prve.Click += LinkButton_prve_Click;//上一页
         LinkButton_next.Click += LinkButton_next_Click;// 下一页
         LinkButton_last.Click += LinkButton_last_Click;//尾页
         DropDownList_jump.SelectedIndexChanged += DropDownList_jump_SelectedIndexChanged;//跳转
     }
 void Button_sel_Click(object sender, EventArgs e)// 查询
     {
         Label_now.Text = "";
         Label1.Text = ReturnTsql(, false);
         Repeater1.DataSource = new CarData().Select(ReturnTsql(, false), hs);
         Repeater1.DataBind();
         Label_max.Text = Maxpage(ReturnTsql(, true), hs).ToString();
         DropDownList_jump.Items.Clear();
         for (int i = ; i <= Maxpage(ReturnTsql(, true), hs); i++)
         {

             DropDownList_jump.Items.Add(new ListItem(i.ToString(), i.ToString()));
         }
     }
     void LinkButton_frist_Click(object sender, EventArgs e)//首页
     {
         Label_now.Text = "";
         Repeater1.DataSource = new CarData().Select(ReturnTsql(, false), hs);
         Repeater1.DataBind();
         //上一页按钮不可用，下一页按钮可用
         LinkButton_next.Enabled = true;
         LinkButton_prve.Enabled = false;
     }
　　　　void LinkButton_next_Click(object sender, EventArgs e)//下一页
     {
         int pagenumber = Convert.ToInt32(Label_now.Text) + ;
         Repeater1.DataSource = new CarData().Select(ReturnTsql(pagenumber, false), hs);
         Repeater1.DataBind();
         Label_now.Text = pagenumber.ToString();//改变当前页数的显示数据
         if (pagenumber >= Maxpage(ReturnTsql(,true),hs))//大于最大页数下一页按钮不可用
         {
             LinkButton_next.Enabled = false;
         }
         LinkButton_prve.Enabled = true;
     }