ASP.net listview下拉项从另一个表获取值

Question

我正在尝试构建一个管理页面，以便让用户创建编辑更新特定表的记录。 “区”表具有以下属性：DistrictID，DistrictName，Description，DistrictImage，CityFK。由于CityFK只是表示“城市”表的CityID的数字，并且对用户没有任何意义，我使用了下拉菜单，它将所有城市名称显示为“DataTextField”，将CityID显示为“DataValueField” ”。但我的目标是将“DataValueField”作为CityFK插入区表中。但每当我输入新的区域记录并从下拉列表中选择一个城市并按下列表视图的“插入”按钮时，关于记录的CityFK就是“0”。

我粘贴整个列表视图，但是如果你看一下InsertItemTemplate或EditItemTemplate的下拉列表，你就是我的意思;

 <asp:ListView ID="DistrictList" runat="server" DataKeyNames="DistrictID" InsertItemPosition="LastItem" DataSourceID="DistrictEntityDataSource" >
    <AlternatingItemTemplate>
        <tr style="background-color:#FFF8DC;">
            <td>
                <asp:Button ID="DeleteButton" runat="server" CommandName="Delete" Text="Delete" />
                <asp:Button ID="EditButton" runat="server" CommandName="Edit" Text="Edit" />
            </td>
            <td>
                <asp:Label ID="DistrictIDLabel" runat="server" Text='<%# Eval("DistrictID") %>' />
            </td>
            <td>
                <asp:Label ID="DistrictNameLabel" runat="server" Text='<%# Eval("DistrictName") %>' />
            </td>
            <td>
                <asp:Label ID="DescriptionLabel" runat="server" Text='<%# Eval("Description") %>' />
            </td>
            <td>
                <asp:Image ID="DistrictImageLabel" runat="server" Height="100px" ImageUrl='<%# "~/Handlers/ImageHandler.ashx?ID="+Eval("DistrictID")+"&Entity=District"%>'/>
            </td>
            <td>
                <asp:Label ID="CityFKLabel" runat="server" Text='<%# Eval("CityFK") %>' />
            </td>
        </tr>
    </AlternatingItemTemplate>
    <EditItemTemplate>
        <tr style="background-color:#008A8C;color: #FFFFFF;">
            <td>
                <asp:Button ID="UpdateButton" runat="server" CommandName="Update" Text="Update" />
                <asp:Button ID="CancelButton" runat="server" CommandName="Cancel" Text="Cancel" />
            </td>
            <td>
                <asp:Label ID="DistrictIDLabel1" runat="server" Text='<%# Eval("DistrictID") %>' />
            </td>
            <td>
                <asp:TextBox ID="DistrictNameTextBox" runat="server" Text='<%# Bind("DistrictName") %>' />
            </td>
            <td>
                <asp:TextBox ID="DescriptionTextBox" runat="server" Text='<%# Bind("Description") %>' />
            </td>
            <td>
                <asp:FileUpload ID="FileUploadDistrict2" runat="server" />

            </td>
             <td>
                <asp:DropDownList ID="CityFKDropDownList" runat="server" AutoPostBack="true" DataSourceID="ddlCityFK_DataSource" ViewStateMode="Enabled"
                    DataTextField="CityName" DataValueField="CityID"
                    AppendDataBoundItems="true">
                    <asp:ListItem Text="-Stadt Wählen-" Value="0" ></asp:ListItem>
                </asp:DropDownList>

                <asp:EntityDataSource ID="ddlCityFK_DataSource" runat="server"
                    ConnectionString="name=MedicalEntities" DefaultContainerName="MedicalEntities"
                    EntitySetName="Cities" >
                </asp:EntityDataSource> 
            </td>

        </tr>
    </EditItemTemplate>
    <EmptyDataTemplate>
        <table runat="server" style="background-color: #FFFFFF;border-collapse: collapse;border-color: #999999;border-style:none;border-width:1px;">
            <tr>
                <td>No data was returned.</td>
            </tr>
        </table>
    </EmptyDataTemplate>
    <InsertItemTemplate>
        <tr style="">
            <td>
                <asp:Button ID="InsertButton" runat="server" CommandName="Insert" Text="Insert" />
                <asp:Button ID="CancelButton" runat="server" CommandName="Cancel" Text="Clear" />
            </td>
            <td>
                <asp:TextBox ID="DistrictIDTextBox" runat="server" Text='<%# Bind("DistrictID") %>' />
            </td>
            <td>
                <asp:TextBox ID="DistrictNameTextBox" runat="server" Text='<%# Bind("DistrictName") %>' />
            </td>
            <td>
                <asp:TextBox ID="DescriptionTextBox" runat="server" Text='<%# Bind("Description") %>' />
            </td>
            <td>
                <asp:FileUpload ID="FileUploadDistrict" runat="server"/>

            </td>
            <td>
                <asp:DropDownList ID="CityFKDropDownList" runat="server" AutoPostBack="true" DataSourceID="ddlCityFK_DataSource" ViewStateMode="Enabled"
                    DataTextField="CityName" DataValueField="CityID"
                    AppendDataBoundItems="true">
                    <asp:ListItem Text="-Stadt Wählen-" Value="0" ></asp:ListItem>
                </asp:DropDownList>

                <asp:EntityDataSource ID="ddlCityFK_DataSource" runat="server"
                    ConnectionString="name=MedicalEntities" DefaultContainerName="MedicalEntities"
                    EntitySetName="Cities">
                </asp:EntityDataSource> 
            </td>
        </tr>
    </InsertItemTemplate>
    <ItemTemplate>
        <tr style="background-color:#DCDCDC;color: #000000;">
            <td>
                <asp:Button ID="DeleteButton" runat="server" CommandName="Delete" Text="Delete" />
                <asp:Button ID="EditButton" runat="server" CommandName="Edit" Text="Edit" />
            </td>
            <td>
                <asp:Label ID="DistrictIDLabel" runat="server" Text='<%# Eval("DistrictID") %>' />
            </td>
            <td>
                <asp:Label ID="DistrictNameLabel" runat="server" Text='<%# Eval("DistrictName") %>' />
            </td>
            <td>
                <asp:Label ID="DescriptionLabel" runat="server" Text='<%# Eval("Description") %>' />
            </td>
            <td>
                <asp:Image ID="DistrictImageLabel" runat="server" Height="100px" ImageUrl='<%# "~/Handlers/ImageHandler.ashx?ID="+Eval("DistrictID")+"&Entity=District"%>'/>
            </td>
            <td>
                <asp:Label ID="CityFKLabel" runat="server" Text='<%# Eval("CityFK") %>' />
            </td>
        </tr>
    </ItemTemplate>
    <LayoutTemplate>
        <table runat="server">
            <tr runat="server">
                <td runat="server">
                    <table id="itemPlaceholderContainer" runat="server" border="1" style="background-color: #FFFFFF;border-collapse: collapse;border-color: #999999;border-style:none;border-width:1px;font-family: Verdana, Arial, Helvetica, sans-serif;">
                        <tr runat="server" style="background-color:#DCDCDC;color: #000000;">
                            <th runat="server"></th>
                            <th runat="server">DistrictID</th>
                            <th runat="server">DistrictName</th>
                            <th runat="server">Description</th>
                            <th runat="server">DistrictImage</th>
                            <th runat="server">CityFK</th>
                        </tr>
                        <tr id="itemPlaceholder" runat="server">
                        </tr>
                    </table>
                </td>
            </tr>
            <tr runat="server">
                <td runat="server" style="text-align: center;background-color: #CCCCCC;font-family: Verdana, Arial, Helvetica, sans-serif;color: #000000;">
                    <asp:DataPager ID="DataPager1" runat="server">
                        <Fields>
                            <asp:NextPreviousPagerField ButtonType="Button" ShowFirstPageButton="True" ShowLastPageButton="True" />
                        </Fields>
                    </asp:DataPager>
                </td>
            </tr>
        </table>
    </LayoutTemplate>
    <SelectedItemTemplate>
        <tr style="background-color:#008A8C;font-weight: bold;color: #FFFFFF;">
            <td>
                <asp:Button ID="DeleteButton" runat="server" CommandName="Delete" Text="Delete" />
                <asp:Button ID="EditButton" runat="server" CommandName="Edit" Text="Edit" />
            </td>
            <td>
                <asp:Label ID="DistrictIDLabel" runat="server" Text='<%# Eval("DistrictID") %>' />
            </td>
            <td>
                <asp:Label ID="DistrictNameLabel" runat="server" Text='<%# Eval("DistrictName") %>' />
            </td>
            <td>
                <asp:Label ID="DescriptionLabel" runat="server" Text='<%# Eval("Description") %>' />
            </td>
            <td>
                <asp:Image ID="DistrictImageLabel" runat="server" Height="100px" ImageUrl='<%# "~/Handlers/ImageHandler.ashx?ID="+Eval("DistrictID")+"&Entity=District"%>'/>
            </td>
            <td>
                <asp:Label ID="CityFKLabel" runat="server" Text='<%# Eval("CityFK") %>' />
            </td>
        </tr>
    </SelectedItemTemplate>
</asp:ListView> 

<asp:EntityDataSource ID="DistrictEntityDataSource" runat="server" ConnectionString="name=MedicalEntities" 
    DefaultContainerName="MedicalEntities" EnableDelete="True" EnableFlattening="False" EnableInsert="True" 
    EnableUpdate="True" EntitySetName="Districts" Include="City" EntityTypeFilter="District">
</asp:EntityDataSource>

所以我试图在插入和编辑操作期间将这些下拉列表值绑定到CityFK。

Answer 1

我明白了。作为解决方法，我使用下拉列表在同一列添加了一个文本框，并将其visible属性设置为false;

<asp:TextBox ID="CityFKTextBoxInsert" runat="server" Visible="false" Text='<%# Bind("CityFK") %>' />

如果你遇到这样的问题，我在这里添加代码隐藏和asp端;

        <InsertItemTemplate>
        <tr style="">
            <td>
                <asp:Button ID="InsertButton" runat="server" CommandName="Insert" Text="Insert" />
                <asp:Button ID="CancelButton" runat="server" CommandName="Cancel" Text="Clear" />
            </td>
            <td>
                <asp:TextBox ID="DistrictIDTextBox" runat="server" Text='<%# Bind("DistrictID") %>' />
            </td>
            <td>
                <asp:TextBox ID="DistrictNameTextBox" runat="server" Text='<%# Bind("DistrictName") %>' />
            </td>
            <td>
                <asp:TextBox ID="DescriptionTextBox" runat="server" Text='<%# Bind("Description") %>' />
            </td>
            <td>
                <asp:FileUpload ID="FileUploadDistrictInsert" runat="server" />

            </td>
            <td>

                <asp:TextBox ID="CityFKTextBoxInsert" runat="server" Visible="false" Text='<%# Bind("CityFK") %>' />
                <asp:DropDownList ID="CityFKDropDownListInsert" runat="server" AutoPostBack="true" DataSourceID="ddlCityFK_DataSource2" ViewStateMode="Enabled"
                    DataTextField="CityName" DataValueField="CityID" OnSelectedIndexChanged="CityFKDropDownListInsert_SelectedIndexChanged"
                    AppendDataBoundItems="true">
                    <asp:ListItem Text="-Stadt Wählen-" Value="0" ></asp:ListItem>
                </asp:DropDownList>

                <asp:EntityDataSource ID="ddlCityFK_DataSource2" runat="server"
                    ConnectionString="name=MedicalEntities" DefaultContainerName="MedicalEntities"
                    EntitySetName="Cities" >
                </asp:EntityDataSource> 

            </td>
        </tr>
    </InsertItemTemplate>

然后我在下拉列表中添加了一个“OnSelectedIndexChanged”事件，并将所选值分配给该文本框;

 protected void CityFKDropDownListInsert_SelectedIndexChanged(object sender, EventArgs e)
    {
        DropDownList DropdownDistrict = (DropDownList)DistrictList.InsertItem.FindControl("CityFKDropDownListInsert");
        TextBox DistrictTextBox = (TextBox)DistrictList.InsertItem.FindControl("CityFKTextBoxInsert");

        DistrictTextBox.Text = DropdownDistrict.SelectedValue;
    }

如果您想将该解决方案也应用于EditItemTemplate，则只需更改该行;

DropDownList DropdownDistrict = (DropDownList)DistrictList.InsertItem.FindControl("CityFKDropDownListInsert");

到此;

DropDownList DropdownDistrict = (DropDownList)DistrictList.EditItem.FindControl("CityFKDropDownListInsert");