Webform（分页与组合查询配合使用）

1.封装实体类

2.写查询方法

//SubjectData类
public List<Subject> Select(string name)
    {
        List<Subject> list = new List<Subject>();
        cmd.CommandText = "select *from Subject where SubjectName like @a ";
        cmd.Parameters.Clear();
        cmd.Parameters.Add("@a","%"+name+"%");
        conn.Open();
        SqlDataReader dr = cmd.ExecuteReader();
        if (dr.HasRows)
        {
            while (dr.Read())
            {
                Subject s = new Subject();
                s.SubjectCode = dr[].ToString();
                s.SubjectName = dr[].ToString();
                list.Add(s);
            }
        }
        conn.Close();

        return list;
    }
//StudentData类
  /// <summary>
    /// 查询方法
    /// </summary>
    /// <param name="tsql">SQL语句</param>
    /// <param name="hh">哈希表</param>
    /// <returns></returns>
    public List<Student> Select(string tsql,Hashtable hh)
    {
        List<Student> list = new List<Student>();
        cmd.CommandText = tsql;
        cmd.Parameters.Clear();
        foreach( string s in hh.Keys)
        {
        cmd.Parameters.Add(s,hh[s]);
        }
        conn.Open();
        SqlDataReader dr = cmd.ExecuteReader();
        if (dr.HasRows)
        {
            while (dr.Read())
            {
                Student s = new Student();
                s.Code = dr[].ToString();
                s.Name = dr[].ToString();
                s.Sex = Convert.ToBoolean(dr[]);
                s.Birthday = Convert.ToDateTime(dr[]);
                s.SubjectCode = dr[].ToString();
                s.Nation = dr[].ToString();
                list.Add(s);
            }
        }
        conn.Close();
        return list;
    }

3.Page_Load部分，最大页方法

int PageCount = ; //每页显示条数
    Hashtable hs = new Hashtable();
 protected void Page_Load(object sender, EventArgs e)
    {
        if(!IsPostBack)
        {
           string tsql = "select top "+PageCount+" *from Student";//查询前PageCount条数据
           //Repeater1数据源指向
            List<Student> list = new StudentData().Select(tsql,hs);
        Repeater1.DataSource = list;
        Repeater1.DataBind();
        Label2.Text = "";//第一页
            //获取最大页
        string sql = "select *from Student";
        Label3.Text = MaxPageNumber(sql,hs).ToString();
 for (int i = ; i <= MaxPageNumber(sql,hs); i++)//给可快速跳转列表框赋值
    {
        DropDownList2.Items.Add(new ListItem(i.ToString(), i.ToString()));
    }
}
}

Page_Load

public int MaxPageNumber(string sql, Hashtable hs)
    {
        List<Student> list = new StudentData().Select(sql, hs);//查询所有数据

        double de = list.Count / (PageCount * 1.0);

        int aa = Convert.ToInt32(Math.Ceiling(de));//取上限
        return aa;
    }

获取最大页

4.根据组合查询拼接语句方法

 /// <summary>
     ///
     /// </summary>
     /// <param name="sql">拼接查询前PageCount条数据的语句</param>
     /// <param name="sql2">查询所有的语句</param>
     /// <param name="tj">用于分页查询与sql等拼接</param>
     /// <param name="count">判断前几项是否为空</param>
     private void Tsql(out string sql, out string sql2,out string tj,out int count)
     {
         count = ;
         sql = "select top " + PageCount + " *from Student";
         sql2 = "select *from Student";
        tj = "";
         //性别不为空
         if (!string.IsNullOrEmpty(tb_sex.Text.Trim()))
         {//判断输入的是男是女，其它输入默认为未输入内容
             if (tb_sex.Text.Trim() == "男")
             {
                 sql += " where Sex = @a";
                 sql2 += " where Sex = @a";
                 tj += " where Sex = @a";
                 hs.Add("@a", "true");
                 count++;
             }
             else if (tb_sex.Text.Trim() == "女")
             {
                 sql += " where Sex = @a";
                 sql2 += " where Sex = @a";
                 tj += " where Sex = @a";
                 hs.Add("@a", "false");
                 count++;
             }
         }
         //年龄不为空
         if (!string.IsNullOrEmpty(tb_age.Text.Trim()))
         {
             int a = DateTime.Now.Year;//获取当前时间的年
             try//确保输入的是数字
             {
                 int ag = Convert.ToInt32(tb_age.Text.Trim());
                 int g = a - ag;
                 DateTime d = Convert.ToDateTime(g.ToString() + "-1-1");
                 if (DropDownList3.SelectedValue == ">=")//小于或等于您输入的年龄,即大于或等于某个时间
                 {
                     if (count == )//前面的一项未输入（性别）
                     {
                         sql += " where Birthday " + DropDownList3.SelectedValue + "@b";
                         sql2 += " where Birthday " + DropDownList3.SelectedValue + "@b";
                         tj += " where Birthday " + DropDownList3.SelectedValue + "@b";
                     }
                     else
                     {
                         sql += " and Birthday " + DropDownList3.SelectedValue + "@b";
                         sql2 += " and Birthday " + DropDownList3.SelectedValue + "@b";
                         tj += " and Birthday " + DropDownList3.SelectedValue + "@b";
                     }
                     hs.Add("@b", d);
                 }
                 else//大于或等于您输入的年龄,即小于或等于某个时间
                 {
                     DateTime dd = Convert.ToDateTime(g.ToString() + "-12-31");
                     if (count == )
                     {
                         sql += " where Birthday " + DropDownList3.SelectedValue + "@b";
                         sql2 += " where Birthday " + DropDownList3.SelectedValue + "@b";
                         tj += " where Birthday " + DropDownList3.SelectedValue + "@b";
                     }
                     else
                     {
                         sql += " and Birthday " + DropDownList3.SelectedValue + "@b";
                         sql2 += " and Birthday " + DropDownList3.SelectedValue + "@b";
                         tj += " and Birthday " + DropDownList3.SelectedValue + "@b";
                     }
                     hs.Add("@b", dd);
                 }
                 count++;
             }
             catch
             {
             }
         }
         if (!string.IsNullOrEmpty(tb_s.Text.Trim()))//判断专业是否为空
         {
             List<Subject> li = new SubjectData().Select(tb_s.Text.Trim());//调用查询方法模糊查询专业
             if (li.Count <= )//未查到数据
             {
             }
             else//查到数据
             {
                 int cou = ;//用于查到的为多条数据
                 foreach (Subject ub in li)
                 {
                     if (li.Count == )//只查到一条数据
                     {
                         if (count == )//性别与年龄输入框都未输入内容
                         {
                             sql += " where SubjectCode =@c";
                             sql2 += " where SubjectCode =@c";
                             tj += " where SubjectCode =@c";
                         }
                         else
                         {
                             sql += " and SubjectCode =@c";
                             sql2 += " and SubjectCode =@c";
                             tj += " and SubjectCode =@c";
                         }
                         hs.Add("@c", ub.SubjectCode);
                         cou++;
                         count++;
                     }
                     else//查到多条数据
                     {
                         if (cou == )//第一次遍历
                         {
                             if (count == )
                             {
                                 sql += " where (SubjectCode =@c";
                                 sql2 += " where (SubjectCode =@c";
                                 tj += " where (SubjectCode =@c";
                             }
                             else//性别与年龄输入框都未输入内容
                             {
                                 sql += " and (SubjectCode =@c";
                                 sql2 += " and (SubjectCode =@c";
                                 tj += " and (SubjectCode =@c";
                             }
                             hs.Add("@c", ub.SubjectCode);
                             cou++;
                         }
                         else
                         {
                             sql += " or SubjectCode =@d)";
                             sql2 += " or SubjectCode =@d)";
                             tj += " or SubjectCode =@d)";
                             hs.Add("@d", ub.SubjectCode);
                         }
                     }

                 }
             }
         }
     }

Tsql方法

5.组合查询 按钮功能赋予

 void Button2_Click(object sender, EventArgs e)
     {
         string sql;//拼接查询前PageCount条数据的语句
         string sql2;//查询所有的语句
         string tj;
         int count;
         Tsql(out sql, out sql2,out tj,out count);
         Repeater1.DataSource = new StudentData().Select(sql, hs);//数据指向
         Repeater1.DataBind();
         Label2.Text = "";
         Label3.Text = MaxPageNumber(sql2,hs).ToString();//获取当前的最大页
         DropDownList2.Items.Clear();
         for (int i = ; i <= MaxPageNumber(sql2,hs); i++)//更新快捷跳转列表框
         {
             DropDownList2.Items.Add(new ListItem(i.ToString(), i.ToString()));
         }
     }

组合查询

6.分页代码

 void btn_next_Click(object sender, EventArgs e)
     {
         int pagec = Convert.ToInt32(Label2.Text) + ;//获取下一页为第几页
         string sql;//拼接查询前PageCount条数据的语句
         string sql2;//查询所有的语句
         string tj;
         int count;
         Tsql(out sql, out sql2, out tj, out count);
         if (pagec > MaxPageNumber(sql2,hs))//当前为最大页
         {
             return;
         }
         else
         {
            if(count>)//进行的是组合查询的下一页跳转
            {
               sql += " and Code not in(select top " + (PageCount * (pagec - )) + " Code from Student " + tj + ")";
            }
             else
            {
                sql += " where Code not in(select top " + (PageCount * (pagec - )) + " Code from Student " + tj + ")";
            }
         }
         Repeater1.DataSource = new StudentData().Select(sql, hs);//数据指向
         Repeater1.DataBind();
         Label2.Text = pagec.ToString();//更新当前页面
         DropDownList2.SelectedValue = pagec.ToString();
     }

下一页

 void btn_prev_Click(object sender, EventArgs e)
     {
         int pagec = Convert.ToInt32(Label2.Text) - ;//获取上一页为第几页
         string sql;//拼接查询前PageCount条数据的语句
         string sql2;
         string tj;
         int count;
         Tsql(out sql, out sql2, out tj, out count);
         if (pagec <= )//当前为第一页
         {
             return;
         }
         if (count > )//进行的是组合查询的上一页跳转
         {
             sql += " and Code not in(select top " + (PageCount * (pagec - )) + " Code from Student " + tj + ")";
         }
         else
         {
             sql += " where Code not in(select top " + (PageCount * (pagec - )) + " Code from Student " + tj + ")";
         }
         List<Student> list = new StudentData().Select(sql, hs);//数据指向
         Repeater1.DataSource = list;
         Repeater1.DataBind();
         Label2.Text = pagec.ToString();//更新当前页面
         DropDownList2.SelectedValue = pagec.ToString();
     }

上一页

 void btn_first_Click(object sender, EventArgs e)
     {
         string sql;
         string sql2;
         string tj;
         int count;
         Tsql(out sql, out sql2, out tj, out count);
         List<Student> list = new StudentData().Select(sql, hs);//数据指向
         Repeater1.DataSource = list;
         Repeater1.DataBind();
         Label2.Text = "";
         DropDownList2.SelectedValue = "";
     }

跳转到第一页

 void btn_end_Click(object sender, EventArgs e)
     {
         string sql;
         string sql2;
         string tj;
         int count;
         Tsql(out sql, out sql2, out tj, out count);
         if (count > )//进行的是组合查询的末页跳转
         {
             sql += " and Code not in(select top " + (PageCount * (MaxPageNumber(sql2,hs) - )) + " Code from Student " + tj + ")";
         }
         else
         {
             sql += " where Code not in(select top " + (PageCount * (MaxPageNumber(sql2, hs) - )) + " Code from Student " + tj + ")";
         }
         List<Student> list = new StudentData().Select(sql, hs);//数据指向
         Repeater1.DataSource = list;
         Repeater1.DataBind();
         Label2.Text = MaxPageNumber(sql2,hs).ToString();
         DropDownList2.SelectedValue = MaxPageNumber(sql2,hs).ToString();
     }

最后一页跳转

 void DropDownList2_SelectedIndexChanged(object sender, EventArgs e)
     {
         string sql;
         string sql2;
         string tj;
         int count;
         Tsql(out sql, out sql2, out tj, out count);
         if (count > )//进行的是组合查询的快捷跳转
         {
             sql += " and Code not in(select top " + (PageCount * (Convert.ToInt32(DropDownList2.SelectedValue) - )) + " Code from Student " + tj + ")";
         }
         else
         {
             sql += " where Code not in(select top " + (PageCount * (Convert.ToInt32(DropDownList2.SelectedValue) - )) + " Code from Student " + tj + ")";
         }
         Repeater1.DataSource = new StudentData().Select(sql, hs);//数据指向
         Repeater1.DataBind();
         Label2.Text = DropDownList2.SelectedValue;
     }

快捷跳转

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