如何通过DropDownList中的SelectedItem到EntityDataSource选择属性

本文介绍了如何通过DropDownList中的SelectedItem到EntityDataSource选择属性的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我想ddlCity DropDownList的选定值传递到EntityDataSource2的CommandText其中WHERE p.city = @city但我得到以下错误：

<tr id="SearchDropDown">
    <asp:EntityDataSource ID="EntityDataSource1" runat="server"
    ConnectionString="name=medicaldb2Entities"
    DefaultContainerName="medicaldb2Entities" EnableFlattening="False"
    EntitySetName="Medicals" Select="it.[medicalName], it.[city], it.[Region]">
</asp:EntityDataSource>
<td>
<td>
<asp:DropDownList ID="ddlCity" runat="server" AutoPostBack="true"
onselectedindexchanged="ddlCity_SelectedIndexChanged"
    DataSourceID="EntityDataSource1" DataTextField="city"
    DataValueField="city">
</asp:DropDownList>
</td>
</tr>
</table>

<asp:ListView ID="ListView1" runat="server" DataSourceID="EntityDataSource2">
<LayoutTemplate>
            <table>
                <tr>
                    <td>
                        City
                    </td>

                </tr>
                <asp:PlaceHolder ID="ItemPlaceHolder" runat="server"></asp:PlaceHolder>
            </table>
        </LayoutTemplate>
        <ItemTemplate>
            <tr>
                <td>
                    <%# Eval("city") %>
                </td>
            </tr>
        </ItemTemplate>

        <EmptyDataTemplate>
            Not Found...
        </EmptyDataTemplate>

</asp:ListView>

<asp:EntityDataSource ID="EntityDataSource2" runat="server"
    CommandText="SELECT p.MedicalID, p.medicalName, p.city, p.Region, p.description, p.Image,     p.adress
          FROM Medicals AS p WHERE p.city = @city"
          AutoGenerateWhereClause="False"
    ConnectionString="name=medicaldb2Entities"
    DefaultContainerName="medicaldb2Entities">

 <WhereParameters>
    <asp:ControlParameter ControlID="ddlCity" DbType="String"
      DefaultValue="2500" Name="city" PropertyName="SelectedValue"
    ConvertEmptyStringToNull="true" />
  </WhereParameters>
 </asp:EntityDataSource>

Any help would be appreciated

解决方案

You can use

<asp:EntityDataSource
....
    <WhereParameters>
        <asp:ControlParameter ControlID="costLimit" DbType="Int32"
          DefaultValue="2500" Name="ordercost" PropertyName="SelectedValue"
        ConvertEmptyStringToNull="true" />
      </WhereParameters>
.....
</asp:EntityDataSource>

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