Question

我正在尝试创建音乐商店应用程序。在服务（实际上是音乐商店）页面上，我创建了一个包含不同音乐流派的下拉列表。我已设法将下拉列表绑定到我的数据库类型。但是当我从下拉列表中选择特定选项时（例如Pop ...），我无法显示数据库中的音乐。

这就是我的代码对services.aspx的看法。

的流派

                <hr class="hrsmallleft wow fadeInDown" data-wow-duration="1000ms" data-wow-delay="600ms" />
            </div>

                <div><strong>POP SONGS</strong></div>


    <div>
    <asp:DropDownList id="DropDownList1" runat="server" DataSourceID="SqlDataSource1" DataTextField="Genre" DataValueField="Name" OnSelectedIndexChanged="DropDown1_SelectedIndexChanged" AutoPostBack="True">
        <asp:ListItem>--Select a Genere--</asp:ListItem>

    </asp:DropDownList>

        <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:RegisterConnectionString %>" SelectCommand="SELECT * FROM [MusicRecord]"></asp:SqlDataSource>

    </div>

    <br />
    <br />

       <div class="col-md-4">
            <div class="panel panel-success wow fadeInDown" data-wow-duration="1000ms" data-wow-delay="600ms">
            <div class="panel-heading">
                <h4>
                    <i class="fa fa-fw fa-check"></i>Katy Perry - Prism</h4>
            </div>
            <div class="panel-body">
                <p>
                    <img src="img/katpop.jpg" height="250" width="294"/>

               </p>
                 <br />
                    <asp:HyperLink ID="HyperLink1" runat="server" CssClass="btn btn-success">Learn More</asp:HyperLink>

            </div>
            </div>
        </div>               
            <!-- 1st content -->
            <div class="col-md-4">
            <div class="panel panel-success wow fadeInDown" data-wow-duration="1000ms" data-wow-delay="600ms">
                <div class="panel-heading">
                    <h4>
                        <i class="fa fa-fw fa-check"></i>Katy Perry - Prism</h4>
                </div>
                <div class="panel-body">
                    <p>
                       <img src="img/katpop.jpg" height="250" width="294"/>

                    </p>
                    <br />
                    <asp:HyperLink ID="HyperLink3" runat="server" CssClass="btn btn-success">Learn More</asp:HyperLink>

                </div>
            </div>
        </div>

            <div class="col-md-4">
            <div class="panel panel-success wow fadeInDown" data-wow-duration="1000ms" data-wow-delay="600ms">
                <div class="panel-heading">
                    <h4>
                        <i class="fa fa-fw fa-check"></i>Katy Perry - Prism</h4>
                </div>
                <div class="panel-body">
                    <p>
                       <img src="img/katpop.jpg" height="250" width="294"/>

                    </p>
                    <br />
                    <asp:HyperLink ID="HyperLink2" runat="server" CssClass="btn btn-success">Learn More</asp:HyperLink>

                </div>
            </div>
        </div>

            <div class="col-md-4">
            <div class="panel panel-success wow fadeInDown" data-wow-duration="1000ms" data-wow-delay="600ms">
                <div class="panel-heading">
                    <h4>
                        <i class="fa fa-fw fa-check"></i>Katy Perry - Prism</h4>
                </div>
                <div class="panel-body">
                    <p>
                       <img src="img/katpop.jpg" height="250" width="294"/>

                    </p>
                    <br />
                    <asp:HyperLink ID="HyperLink4" runat="server" CssClass="btn btn-success">Learn More</asp:HyperLink>

                </div>
            </div>
        </div>

            <div class="col-md-4">
            <div class="panel panel-success wow fadeInDown" data-wow-duration="1000ms" data-wow-delay="600ms">
                <div class="panel-heading">
                    <h4>
                        <i class="fa fa-fw fa-check"></i>Katy Perry - Prism</h4>
                </div>
                <div class="panel-body">
                    <p>
                       <img src="img/katpop.jpg" height="250" width="294"/>

                    </p>
                    <br />
                    <asp:HyperLink ID="HyperLink5" runat="server" CssClass="btn btn-success">Learn More</asp:HyperLink>

                </div>
            </div>
        </div>

            <div class="col-md-4">
            <div class="panel panel-success wow fadeInDown" data-wow-duration="1000ms" data-wow-delay="600ms">
                <div class="panel-heading">
                    <h4>
                        <i class="fa fa-fw fa-check"></i>Katy Perry - Prism</h4>
                </div>
                <div class="panel-body">
                    <p>
                       <img src="img/katpop.jpg" height="250" width="294"/>

                    </p>
                    <br />
                    <asp:HyperLink ID="HyperLink6" runat="server" CssClass="btn btn-success">Learn More</asp:HyperLink>

                </div>
            </div>
        </div>

        </div>
    </div>
</div>

Answer 1

将选定的值属性添加到下拉列表

 <asp:DropDownList id="DropDownList1" runat="server" DataSourceID="SqlDataSource1" DataTextField="Genre" DataValueField="Name" OnSelectedIndexChanged="DropDown1_SelectedIndexChanged" AutoPostBack="True" SelectedValue='<%# Eval("Name") %>'>
    <asp:ListItem>--Select a Genere--</asp:ListItem>

Answer 2

为什么不摆脱SQL数据源控件。将实体框架添加到您的项目中。运行LINQ查询并将结果绑定到DropdownList。然后“OnSelectedIndexChanged”事件运行另一个LINQ查询以从数据库中提取数据。

using (var rep = new efEntities()){
     var results= rep.Genre.ToList();
     // bind
     DropDownList1.datasource=results;
     DropDownList1.DataTextField="";
     DropDownList1.DataValueField="";
     DropDownList1.DataBind();
}

protected void DropDownList1_selectedindexChanged(){
    int genreID = convert.toint32(DropDownList1.selectedvalue);
    // search database
    using (var rep = new efEntities()){
    var results = rep.Music.Where(m=>m.genreID==genreID).ToList();

    // loop to get results
    foreach(var item in results){
        //do stuff
}
}
}

如何将下拉菜单链接到包含产品的数据库并在ASP中显示这些产品？

2 个答案: