Webform（分页与组合查询配合使用）

Posted 2020-08-15 fei！

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

 1  int PageCount = 5; //每页显示条数
 2     Hashtable hs = new Hashtable();
 3  protected void Page_Load(object sender, EventArgs e)
 4     {
 5         if(!IsPostBack)
 6         {
 7            string tsql = "select top "+PageCount+" *from Student";//查询前PageCount条数据
 8            //Repeater1数据源指向
 9             List<Student> list = new StudentData().Select(tsql,hs);
10         Repeater1.DataSource = list;
11         Repeater1.DataBind();
12         Label2.Text = "1";//第一页
13             //获取最大页
14         string sql = "select *from Student";
15         Label3.Text = MaxPageNumber(sql,hs).ToString();
16  for (int i = 1; i <= MaxPageNumber(sql,hs); i++)//给可快速跳转列表框赋值
17     {
18         DropDownList2.Items.Add(new ListItem(i.ToString(), i.ToString()));
19     }
20 }
21 }

Page_Load

1  public int MaxPageNumber(string sql, Hashtable hs)
2     {
3         List<Student> list = new StudentData().Select(sql, hs);//查询所有数据
4 
5         double de = list.Count / (PageCount * 1.0);
6 
7         int aa = Convert.ToInt32(Math.Ceiling(de));//取上限
8         return aa;
9     }

获取最大页

4.根据组合查询拼接语句方法

  1  /// <summary>
  2     /// 
  3     /// </summary>
  4     /// <param name="sql">拼接查询前PageCount条数据的语句</param>
  5     /// <param name="sql2">查询所有的语句</param>
  6     /// <param name="tj">用于分页查询与sql等拼接</param>
  7     /// <param name="count">判断前几项是否为空</param>
  8     private void Tsql(out string sql, out string sql2,out string tj,out int count)
  9     {
 10         count = 0;
 11         sql = "select top " + PageCount + " *from Student";
 12         sql2 = "select *from Student";
 13        tj = "";
 14         //性别不为空
 15         if (!string.IsNullOrEmpty(tb_sex.Text.Trim()))
 16         {//判断输入的是男是女，其它输入默认为未输入内容
 17             if (tb_sex.Text.Trim() == "男")
 18             {
 19                 sql += " where Sex = @a";
 20                 sql2 += " where Sex = @a";
 21                 tj += " where Sex = @a";
 22                 hs.Add("@a", "true");
 23                 count++;
 24             }
 25             else if (tb_sex.Text.Trim() == "女")
 26             {
 27                 sql += " where Sex = @a";
 28                 sql2 += " where Sex = @a";
 29                 tj += " where Sex = @a";
 30                 hs.Add("@a", "false");
 31                 count++;
 32             }
 33         }
 34         //年龄不为空
 35         if (!string.IsNullOrEmpty(tb_age.Text.Trim()))
 36         {
 37             int a = DateTime.Now.Year;//获取当前时间的年
 38             try//确保输入的是数字
 39             {
 40                 int ag = Convert.ToInt32(tb_age.Text.Trim());
 41                 int g = a - ag;
 42                 DateTime d = Convert.ToDateTime(g.ToString() + "-1-1");
 43                 if (DropDownList3.SelectedValue == ">=")//小于或等于您输入的年龄,即大于或等于某个时间
 44                 {
 45                     if (count == 0)//前面的一项未输入（性别）
 46                     {
 47                         sql += " where Birthday " + DropDownList3.SelectedValue + "@b";
 48                         sql2 += " where Birthday " + DropDownList3.SelectedValue + "@b";
 49                         tj += " where Birthday " + DropDownList3.SelectedValue + "@b";
 50                     }
 51                     else
 52                     {
 53                         sql += " and Birthday " + DropDownList3.SelectedValue + "@b";
 54                         sql2 += " and Birthday " + DropDownList3.SelectedValue + "@b";
 55                         tj += " and Birthday " + DropDownList3.SelectedValue + "@b";
 56                     }
 57                     hs.Add("@b", d);
 58                 }
 59                 else//大于或等于您输入的年龄,即小于或等于某个时间
 60                 {
 61                     DateTime dd = Convert.ToDateTime(g.ToString() + "-12-31");
 62                     if (count == 0)
 63                     {
 64                         sql += " where Birthday " + DropDownList3.SelectedValue + "@b";
 65                         sql2 += " where Birthday " + DropDownList3.SelectedValue + "@b";
 66                         tj += " where Birthday " + DropDownList3.SelectedValue + "@b";
 67                     }
 68                     else
 69                     {
 70                         sql += " and Birthday " + DropDownList3.SelectedValue + "@b";
 71                         sql2 += " and Birthday " + DropDownList3.SelectedValue + "@b";
 72                         tj += " and Birthday " + DropDownList3.SelectedValue + "@b";
 73                     }
 74                     hs.Add("@b", dd);
 75                 }
 76                 count++;
 77             }
 78             catch
 79             {
 80             }
 81         }
 82         if (!string.IsNullOrEmpty(tb_s.Text.Trim()))//判断专业是否为空
 83         {
 84             List<Subject> li = new SubjectData().Select(tb_s.Text.Trim());//调用查询方法模糊查询专业
 85             if (li.Count <= 0)//未查到数据
 86             {
 87             }
 88             else//查到数据
 89             {
 90                 int cou = 0;//用于查到的为多条数据
 91                 foreach (Subject ub in li)
 92                 {
 93                     if (li.Count == 1)//只查到一条数据
 94                     {
 95                         if (count == 0)//性别与年龄输入框都未输入内容
 96                         {
 97                             sql += " where SubjectCode =@c";
 98                             sql2 += " where SubjectCode =@c";
 99                             tj += " where SubjectCode =@c";
100                         }
101                         else
102                         {
103                             sql += " and SubjectCode =@c";
104                             sql2 += " and SubjectCode =@c";
105                             tj += " and SubjectCode =@c";
106                         }
107                         hs.Add("@c", ub.SubjectCode);
108                         cou++;
109                         count++;
110                     }
111                     else//查到多条数据
112                     {
113                         if (cou == 0)//第一次遍历
114                         {
115                             if (count == 0)
116                             {
117                                 sql += " where (SubjectCode =@c";
118                                 sql2 += " where (SubjectCode =@c";
119                                 tj += " where (SubjectCode =@c";
120                             }
121                             else//性别与年龄输入框都未输入内容
122                             {
123                                 sql += " and (SubjectCode =@c";
124                                 sql2 += " and (SubjectCode =@c";
125                                 tj += " and (SubjectCode =@c";
126                             }
127                             hs.Add("@c", ub.SubjectCode);
128                             cou++;
129                         }
130                         else
131                         {
132                             sql += " or SubjectCode =@d)";
133                             sql2 += " or SubjectCode =@d)";
134                             tj += " or SubjectCode =@d)";
135                             hs.Add("@d", ub.SubjectCode);
136                         }
137                     }
138 
139                 }
140             }
141         }
142     }

Tsql方法

5.组合查询 按钮功能赋予

 1  void Button2_Click(object sender, EventArgs e)
 2     {       
 3         string sql;//拼接查询前PageCount条数据的语句
 4         string sql2;//查询所有的语句
 5         string tj;
 6         int count;
 7         Tsql(out sql, out sql2,out tj,out count);
 8         Repeater1.DataSource = new StudentData().Select(sql, hs);//数据指向
 9         Repeater1.DataBind();
10         Label2.Text = "1";
11         Label3.Text = MaxPageNumber(sql2,hs).ToString();//获取当前的最大页
12         DropDownList2.Items.Clear();
13         for (int i = 1; i <= MaxPageNumber(sql2,hs); i++)//更新快捷跳转列表框
14         {
15             DropDownList2.Items.Add(new ListItem(i.ToString(), i.ToString()));
16         }
17     }

组合查询

6.分页代码

 1  void btn_next_Click(object sender, EventArgs e)
 2     {
 3         int pagec = Convert.ToInt32(Label2.Text) + 1;//获取下一页为第几页
 4         string sql;//拼接查询前PageCount条数据的语句
 5         string sql2;//查询所有的语句
 6         string tj;
 7         int count;
 8         Tsql(out sql, out sql2, out tj, out count);
 9         if (pagec > MaxPageNumber(sql2,hs))//当前为最大页
10         {
11             return;
12         }
13         else
14         {
15            if(count>0)//进行的是组合查询的下一页跳转
16            {
17               sql += " and Code not in(select top " + (PageCount * (pagec - 1)) + " Code from Student " + tj + ")";
18            }
19             else
20            {
21                sql += " where Code not in(select top " + (PageCount * (pagec - 1)) + " Code from Student " + tj + ")";
22            }
23         }
24         Repeater1.DataSource = new StudentData().Select(sql, hs);//数据指向
25         Repeater1.DataBind();
26         Label2.Text = pagec.ToString();//更新当前页面
27         DropDownList2.SelectedValue = pagec.ToString();
28     }

下一页

 1   void btn_prev_Click(object sender, EventArgs e)
 2     {
 3         int pagec = Convert.ToInt32(Label2.Text) - 1;//获取上一页为第几页
 4         string sql;//拼接查询前PageCount条数据的语句
 5         string sql2;
 6         string tj;
 7         int count;
 8         Tsql(out sql, out sql2, out tj, out count);
 9         if (pagec <= 0)//当前为第一页
10         {
11             return;
12         }
13         if (count > 0)//进行的是组合查询的上一页跳转
14         {
15             sql += " and Code not in(select top " + (PageCount * (pagec - 1)) + " Code from Student " + tj + ")";
16         }
17         else
18         {
19             sql += " where Code not in(select top " + (PageCount * (pagec - 1)) + " Code from Student " + tj + ")";
20         }
21         List<Student> list = new StudentData().Select(sql, hs);//数据指向
22         Repeater1.DataSource = list;
23         Repeater1.DataBind();
24         Label2.Text = pagec.ToString();//更新当前页面
25         DropDownList2.SelectedValue = pagec.ToString();
26     }

上一页

 1   void btn_first_Click(object sender, EventArgs e)
 2     {
 3         string sql;
 4         string sql2;
 5         string tj;
 6         int count;
 7         Tsql(out sql, out sql2, out tj, out count);
 8         List<Student> list = new StudentData().Select(sql, hs);//数据指向
 9         Repeater1.DataSource = list;
10         Repeater1.DataBind();
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