WebForm 分页与组合查询

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[0].ToString();
                s.SubjectName = dr[1].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[0].ToString();
                s.Name = dr[1].ToString();
                s.Sex = Convert.ToBoolean(dr[2]);
                s.Birthday = Convert.ToDateTime(dr[3]);
                s.SubjectCode = dr[4].ToString();
                s.Nation = dr[5].ToString();
                list.Add(s);
            }
        }
        conn.Close();
        return list;
    }

查询方法

3.Page_Load部分，最大页方法

int PageCount = 5; //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 = "1";//第一页
            //获取最大页
        string sql = "select *from Student";
        Label3.Text = MaxPageNumber(sql,hs).ToString();
 for (int i = 1; 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 = 0;
        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 == 0)//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 == 0)
                    {
                        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 <= 0)//未查到数据
            {
            }
            else//查到数据
            {
                int cou = 0;//用于查到的为多条数据
                foreach (Subject ub in li)
                {
                    if (li.Count == 1)//只查到一条数据
                    {
                        if (count == 0)//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 == 0)//第一次遍历
                        {
                            if (count == 0)
                            {
                                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 = "1";
        Label3.Text = MaxPageNumber(sql2,hs).ToString();//获取当前的最大页
        DropDownList2.Items.Clear();
        for (int i = 1; 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) + 1;//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>0)//进行的是组合查询的下一页跳转
           {
              sql += " and Code not in(select top " + (PageCount * (pagec - 1)) + " Code from Student " + tj + ")";
           }
            else
           {
               sql += " where Code not in(select top " + (PageCount * (pagec - 1)) + " 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) - 1;//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 <= 0)//当前为第一页
        {
            return;
        }
        if (count > 0)//进行的是组合查询的上一页跳转
        {
            sql += " and Code not in(select top " + (PageCount * (pagec - 1)) + " Code from Student " + tj + ")";
        }
        else
        {
            sql += " where Code not in(select top " + (PageCount * (pagec - 1)) + " 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 = "1";
        DropDownList2.SelectedValue = "1";
    }

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 > 0)//进行的是组合查询的末页跳转
        {
            sql += " and Code not in(select top " + (PageCount * (MaxPageNumber(sql2,hs) - 1)) + " Code from Student " + tj + ")";
        }
        else
        {
            sql += " where Code not in(select top " + (PageCount * (MaxPageNumber(sql2, hs) - 1)) + " 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 > 0)//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) - 1)) + " Code from Student " + tj + ")";
        }
        else
        {
            sql += " where Code not in(select top " + (PageCount * (Convert.ToInt32(DropDownList2.SelectedValue) - 1)) + " 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