Dropdownlist Datasource by LINQ查询
Dropdownlist Datasource by LINQ查询
提问于 2013-09-08 00:25:39
我不知道为什么当ddlMedicalName的值改变时，ddlCity不会被填充。我只是尝试构建函数"ddlMedicalName_SelectedIndexChanged“，以便如果有人从下拉列表ddlMedicalName中选择任何一个MedicalName，则应根据ddlMedicalName的选择值填充另一个下拉列表"ddlCity”数据源。
代码隐藏：
protected void ddlMedicalName_OnSelectedIndexChanged(object sender, EventArgs e)
{
//string entityString = ConfigurationManager.ConnectionStrings["medicaldb2Entities"].ConnectionString;
//EntityDataSource eds = new EntityDataSource();
using (Entity.medicaldbEntities context = new Entity.medicaldbEntities())
{
string selected = ddlMedicalName.SelectedItem.Value;
int slct = Convert.ToInt32(selected);
var orders = from order in context.Cities
where order.CityID == slct
select new { order.CityID, order.CityName };
var lstSrc = orders.ToList();
ddlCity.DataSource = lstSrc;
ddlCity.DataTextField = "CityName";
ddlCity.DataValueField = "CityID";
ddlCity.DataBind();
}
}ASPX：
<tr id="SearchDropDown">
<asp:EntityDataSource ID="EntityDataSource1" runat="server"
ConnectionString="name=medicaldbEntities"
DefaultContainerName="medicaldbEntities" EnableFlattening="False"
EntitySetName="Medicals" Select="it.[medicalName],it.[CityFK]">
</asp:EntityDataSource>
<td>
<asp:DropDownList ID="ddlMedicalName" runat="server" AutoPostBack="false"
OnSelectedIndexChanged="ddlMedicalName_OnSelectedIndexChanged"
DataSourceID="EntityDataSource1" DataTextField="MedicalName"
DataValueField="CityFK">
</asp:DropDownList>
</td>
<td>
<asp:DropDownList ID="ddlRegion" runat="server" AutoPostBack="true"
OnSelectedIndexChanged="ddlRegion_SelectedIndexChanged"
DataSourceID="EntityDataSource1" DataTextField="MedicalName"
DataValueField="MedicalName">
</asp:DropDownList>
</td>
<td>
<asp:DropDownList ID="ddlCity" runat="server" AutoPostBack="false"
OnSelectedIndexChanged="ddlCity_SelectedIndexChanged"
DataTextField="CityID"
DataValueField="CityID">
</asp:DropDownList>
</td>
<td>
<asp:Button ID="SearchButton" runat="server" Text="Suche" onclick="SearchButton_Click" />
</td>
</tr>这就是我得到的错误：
如果我将其更改为：
List<string> lstSrc = orders.ToList();它不会抛出任何错误，但也不能工作(未填充ddlCity)。
Stack Overflow用户
发布于 2014-03-21 17:39:38
我的问题非常具体；在master.site的main form标签上有一个警告。表单的结束标记已经存在，但由于一些不允许的控件或标记，它没有被检测到，也没有呈现，这导致了奇怪的下拉列表问题的原因。然后我编辑了我的html和main form标签，摆脱了"Form1没有结束标签“的警告，一切都恢复正常了。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/18675406
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