按年龄组对网格视图进行排序的最佳方法

Question

我正在使用 Visual Studio 在 C# 中创建一个 asp.net Web 应用程序。我有一个注册页面，孩子们可以在其中注册，然后他们的详细信息被发送到我数据库中的“孩子”表中，点击“查看已注册的孩子”按钮后，会打开一个新页面，其中显示名字、出生日期和用户名（ pk) 的每个注册儿童。按照目前的情况，DOB 被存储并读取为“04/02/2006”。我现在需要找到一种从 DOB 获取年龄并能够按年龄组（6-10、11-13、14-16）查看孩子的方法。

我想知道实现这一目标的最简单方法是什么？每个年龄组的单选按钮，即在选择时，只显示GridView中该年龄组中的孩子。或者当页面被加载并且所有的孩子都显示在网格视图上时，他们已经被分类到年龄组中？

请记住，我是 C# 和 asp.net 的新手，谁能告诉我实现这一目标的最简单方法！我附上了我的 gridview 当前外观的屏幕截图。提前致谢。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Configuration;
using System.Data.SqlClient;

namespace Coursework
{
public partial class Testy1 : System.Web.UI.Page
{
    //create a datasource
    SqlDataSource source = new SqlDataSource();

    protected void Page_Load(object sender, EventArgs e)
    {
        //always set some defaults for the sqldatasource
        source.ID = "source1";
        SqlConnection connectionString = new SqlConnection(ConfigurationManager.ConnectionStrings["newregDBConnectionString"].ConnectionString);
        source.SelectCommand = "SELECT firstname, dob, DATEDIFF(hour, dob, GETDATE()) / 8766 AS age FROM table ORDER BY age";

        if (!IsPostBack)
        {
            //bind the grid
            GridView1.DataSource = source;
            GridView1.DataBind();
        }
    }

    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        //the new database query, now with where clause
        source.SelectCommand = "SELECT firstname, dob, DATEDIFF(hour, dob, GETDATE()) / 8766 AS age FROM table WHERE (DATEDIFF(hour, dob, GETDATE()) / 8766 BETWEEN @start AND @end) ORDER BY age";

        //get the end age from the dropdown and cast as int
        int end = Convert.ToInt32(DropDownList1.SelectedValue);

        //get the start int for the filter
        int start = end - 5;

        //if the filter is resetted, make sure the query returns all ages
        if (end == 0)
        {
            start = 0;
            end = 99;
        }

        //replace the parameters in the query
        source.SelectParameters.Add("start", start.ToString());
        source.SelectParameters.Add("end", end.ToString());

        //rebind the grid
        GridView1.DataSource = source;
        GridView1.DataBind();
    }
}

}

Answer 1

你可以从这个 sn-p 开始。您需要做的第一件事是编辑从数据库中获取数据的查询。添加以下内容：DATEDIFF(hour, dob, GETDATE()) / 8766 as AGE，这将为您提供数据库中人员的年龄。然后，您可以使用它按年龄进行过滤。

然后将一个 DropDownList 添加到页面，其中包含 OnSelectedIndexChanged 事件并将 AutoPostback 设置为 true。

<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="true" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
    <asp:ListItem Text="Filter age" Value="0"></asp:ListItem>
    <asp:ListItem Text="0 - 5" Value="5"></asp:ListItem>
    <asp:ListItem Text="6 - 10" Value="10"></asp:ListItem>
    <asp:ListItem Text="10 - 15" Value="15"></asp:ListItem>
</asp:DropDownList>

<asp:GridView ID="GridView1" runat="server">
    <Columns>
        <asp:TemplateField>
            <ItemTemplate>
                <%# Eval("firstname") %>
            </ItemTemplate>
        </asp:TemplateField>
        <asp:TemplateField>
            <ItemTemplate>
                <%# Convert.ToDateTime(Eval("dob")).ToString("d MMMM yyyy") %>
            </ItemTemplate>
        </asp:TemplateField>
        <asp:TemplateField>
            <ItemTemplate>
                <%# Eval("age") %>
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

然后在后面的代码中

using System;
......

namespace Project1
{
    public partial class WebForm1: System.Web.UI.Page
    {
        //create a datasource
        SqlDataSource source = new SqlDataSource();

        protected void Page_Load(object sender, EventArgs e)
        {
            //always set some defaults for the sqldatasource
            source.ID = "source1";
            source.ConnectionString = "connectionString";
            source.SelectCommand = "SELECT firstname, dob, DATEDIFF(hour, dob, GETDATE()) / 8766 AS age FROM table ORDER BY age";

            if (!IsPostBack)
            {
                //bind the grid
                GridView1.DataSource = source;
                GridView1.DataBind();
            }
        }

        protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
        {
            //the new database query, now with where clause
            source.SelectCommand = "SELECT firstname, dob, DATEDIFF(hour, dob, GETDATE()) / 8766 AS age FROM table WHERE (DATEDIFF(hour, dob, GETDATE()) / 8766 BETWEEN @start AND @end) ORDER BY age";

            //get the end age from the dropdown and cast as int
            int end = Convert.ToInt32(DropDownList1.SelectedValue);

            //get the start int for the filter
            int start = end - 5;

            //if the filter is resetted, make sure the query returns all ages
            if (end == 0)
            {
                start = 0;
                end = 99;
            }

            //replace the parameters in the query
            source.SelectParameters.Add("start", start.ToString());
            source.SelectParameters.Add("end", end.ToString());

            //rebind the grid
            GridView1.DataSource = source;
            GridView1.DataBind();
        }
    }
}