.net 组合查询

首先写HTML布局:

 <style type="text/css">
        #tab1 {
             100%;
            text-align: center;
            background-color: navy;
            border-spacing: 1px; /*边框之间的空隙变成1像素*/
        }

            #tab1 thead tr {
                color: white;
            }

            #tab1 tbody tr {
                background-color: white;
            }

            #tab1 td {
                padding: 7px 5px;
            }

            #tab1 tbody tr:hover {
                background-color: #f00; /*//鼠标移入时候的背景颜色*/
            }
       
    </style>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    <table id="tab1">
        <br />
       
        昵称:<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>&nbsp;&nbsp;&nbsp;
        性别:<asp:DropDownList ID="DropDownList1" runat="server">
             <asp:ListItem Value="true">全部</asp:ListItem>
            <asp:ListItem >男</asp:ListItem>
             <asp:ListItem>女</asp:ListItem>
        </asp:DropDownList>
         &nbsp;&nbsp;&nbsp;
        生日:<asp:DropDownList ID="DropDownList2" runat="server">
            <asp:ListItem Value="true">全部</asp:ListItem>
            <asp:ListItem Value=">=">大于等于</asp:ListItem>
             <asp:ListItem Value="<=">小于等于</asp:ListItem>
           </asp:DropDownList>
        <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
        &nbsp;&nbsp;&nbsp;
        <asp:Button ID="Button1" runat="server" Text="查询" />
        <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
          <br />
          <br />
          <br />
                <thead>
                    <tr>
                        <td>ID</td>
                        <td>编号</td>
                        <td>用户名</td>
                        <td>密码</td>
                        <td>昵称</td>
                        <td>性别</td>
                        <td>生日</td>
                        <td>民族</td>
                       
                    </tr>
                </thead>
                <tbody>
                    <asp:Repeater ID="Repeater1" runat="server">
                        <%-- 在内容里加Repeater和TtemTemplate--%>
                        <ItemTemplate>
                            <tr>
                                <td><%#Eval("ID") %></td>
                                <td><%#Eval("ucode") %></td>
                                <td><%#Eval("username") %></td>
                                <td><%#Eval("password") %></td>
                                <td><%#Eval("nickname") %></td>
                                <td><%#Eval("sexstr") %>
                                    <%-- <img src="<%#Eval("sexImg") %>" />--%>  <%--使用图片当性别区分--%>
                                </td>
                                <td><%#Eval("birthday","{0:yyyy年MM月dd日}") %></td>
                                <%-- 日期的转换--%>
                                <td><%#Eval("NationName") %></td>   
                            </tr>
                        </ItemTemplate>
                    </asp:Repeater>
                </tbody>
            </table>
    </div>
    </form>
</body>
</html>

然后后台代码:

 protected void Page_Load(object sender, EventArgs e)
    {
        Button1.Click += Button1_Click;
        if(!IsPostBack)
        {
            Repeater1.DataSource = new UsersData().SelectAll();
            Repeater1.DataBind();
        }
    }

    void Button1_Click(object sender, EventArgs e)
    {
        
       //获取要查询的条件,拼接sql语句
        int count = 0;
        string sql = "select *from Users";
        Hashtable hs = new Hashtable();
        if(TextBox1.Text.Trim().Length>0)
        {
            sql += " where nickname like @a";
            hs.Add("@a","%"+TextBox1.Text.Trim()+"%");
            count++;
        }
        if (DropDownList1.SelectedIndex!=0 )   //索引为0就是 不选全部
        {
            if (count > 0)
            {
                sql += " and sex =" + (DropDownList1.SelectedValue == "" ? "1" : "0");
            }
            else
            {

                sql += " where sex =" + (DropDownList1.SelectedValue == "" ? "1" : "0");
            }
            count++;
        }

        if ( TextBox2.Text.Trim().Length > 0)
        {
            if (count > 0)
            {
                sql += " and Year(birthday)" + DropDownList2.SelectedValue + TextBox2.Text;
            }
            else
            {
                sql += " where Year(birthday)" + DropDownList2.SelectedValue + TextBox2.Text;
            }
          
            count++;

        }

      
        //Label1.Text = sql;   //测试用的
        //执行语句并接收返回值绑定,展示数据;
        Repeater1.DataSource = new UsersData().Selectsql(sql, hs);
        Repeater1.DataBind();
     
    }

用到的方法:

 public List<Users> SelectAll()
    {
        List<Users> ulist = new List<Users>();
        cmd.CommandText = "select *from Users";
        conn.Open();
        SqlDataReader dr = cmd.ExecuteReader();
        while (dr.Read())
        {
            Users u = new Users();
            u.ID = Convert.ToInt32(dr[0]);
            u.ucode = dr[1].ToString();
            u.username = dr[2].ToString();
            u.password = dr[3].ToString();
            u.nickname = dr[4].ToString();
            u.sex = Convert.ToBoolean(dr[5]);
            u.birthday = Convert.ToDateTime(dr[6]);
            u.nation = dr[7].ToString();
            ulist.Add(u);
        }
        conn.Close();
        return ulist;
    }

 public List<Users> Selectcount(int NowNumber, int Count)   //NowNumber当前要看的页数,Count当前页的条数
    {
        List<Users> ulist = new List<Users>();
        cmd.CommandText = "select top " + Count + " *from Users where ID not in(select top " + ((NowNumber - 1) * Count) + " ID from Users)";  //分页方法 ,把count放进去,查询前几条。后面也页数条数,就是前去前面的页数的条数。
        conn.Open();
        SqlDataReader dr = cmd.ExecuteReader();
        while (dr.Read())
        {
            Users u = new Users();
            u.ID = Convert.ToInt32(dr[0]);
            u.ucode = dr[1].ToString();
            u.username = dr[2].ToString();
            u.password = dr[3].ToString();
            u.nickname = dr[4].ToString();
            u.sex = Convert.ToBoolean(dr[5]);
            u.birthday = Convert.ToDateTime(dr[6]);
            u.nation = dr[7].ToString();
            ulist.Add(u);
        }
        conn.Close();
        return ulist;
    }

 
    public List<Users> Selectsql(string sql,Hashtable hs)
    {
        List<Users> ulist = new List<Users>();
        cmd.CommandText = sql;
        cmd.Parameters.Clear();
        foreach(string s in hs.Keys)
        {
            cmd.Parameters.AddWithValue(s,hs[s]);
        }
        conn.Open();
        SqlDataReader dr = cmd.ExecuteReader();
        while (dr.Read())
        {
            Users u = new Users();
            u.ID = Convert.ToInt32(dr["ID"]);
            u.ucode = dr["ucode"].ToString();
            u.username = dr["username"].ToString();
            u.password = dr["password"].ToString();
            u.nickname = dr["nickname"].ToString();
            u.sex = Convert.ToBoolean(dr["sex"]);
            u.birthday = Convert.ToDateTime(dr["birthday"]);
            u.nation = dr["nation"].ToString();
            ulist.Add(u);
        }
        conn.Close();
        return ulist;
    }

所有的的理解都写在了代码里面,方便下次看的时候理解。

原文地址:https://www.cnblogs.com/liuyubin0629/p/7327410.html