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

View Code

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

View Code

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

View Code

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

首页

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

末页

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