Dropdown-Liste in der Listenansicht Elementvorlage einfügen, die Null an die Datenbank übergibt?

Question

Wenn ich Dropdown-Liste innerhalb der Listview anwenden fügen sie nur Nullwert warum?

Momentan habe ich eine Dropdown-Liste mit ihrer eigenen sqldatasource, die die Dropdownliste füllt. Das ddl befindet sich in einer ListView, die auch auf sqldatasource, Elementvorlage einfügen hat. Wenn wir jedoch auf Einfügen klicken, ist der Wert, der an dbase übergeben wird, null.

<asp:DropDownList ID="DropDownList1" SelectedValue= '<%# Bind("NationalityId") %>' CssClass="form-control" runat="server" 
DataSourceID="SqlDataSource1" DataTextField="NationalityName" DataValueField="NationalityId"> 
    </asp:DropDownList> 
    <asp:SqlDataSource runat="server" ID="SqlDataSource1" ConnectionString='<%$ ConnectionStrings:CRMSConnectionString %>' SelectCommand="SELECT * FROM [Nationality]"> 
     </asp:SqlDataSource> 

Answer 1

<asp:ListView ID="ListView1" runat="server" DataSourceID="SqlDataSource3" DataKeyNames="AreaId" InsertItemPosition="LastItem"> 
<InsertItemTemplate> 
       <tr style=""> 
        <td> 
         <asp:Button runat="server" CommandName="Insert" Text="Insert" ID="InsertButton" CssClass="btn-warning" Width="50px" Height="25px" /> 
         <asp:Button runat="server" CommandName="Cancel" Text="Clear" ID="CancelButton" CssClass="btn-warning" Width="50px" Height="25px" /> 
        </td> 
        <td> 
         <asp:UpdateProgress ID="UpdateProgress1" runat="server"> 
          <ProgressTemplate> 
           <img alt="as" src="Images/loader1.gif" style="width: 30px; height: 30px" /> 
          </ProgressTemplate> 
         </asp:UpdateProgress> 
        </td> 
        <td> 
         <asp:DropDownList ID="DropDownList1" runat="server" SelectedValue='<%# Bind("ProvinceId") %>' CssClass="form-control" AutoPostBack="true" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged" DataSourceID="SqlDataSource4" DataTextField="ProvinceName" DataValueField="ProvinceId"></asp:DropDownList> 
         <asp:SqlDataSource runat="server" ID="SqlDataSource4" ConnectionString='<%$ ConnectionStrings:CRMSConnectionString %>' SelectCommand="SELECT * FROM [Province]"></asp:SqlDataSource> 
        </td> 
        <td> 
         <asp:DropDownList ID="DropDownList4" runat="server" SelectedValue='<%# Bind("CityId") %>' CssClass="form-control" DataSourceID="SqlDataSource5" DataTextField="CityName" DataValueField="CityId"></asp:DropDownList> 
         <asp:SqlDataSource runat="server" ID="SqlDataSource5" ConnectionString='<%$ ConnectionStrings:CRMSConnectionString %>' SelectCommand="SELECT City.CityId, City.CityName FROM City INNER JOIN Province ON City.ProvinceId = Province.ProvinceId WHERE (City.ProvinceId = @ProvinceId)"> 
          <SelectParameters> 
           <asp:ControlParameter ControlID="DropDownList1" PropertyName="SelectedValue" Name="ProvinceId"></asp:ControlParameter> 
          </SelectParameters> 
         </asp:SqlDataSource> 
        </td> 
        <td> 
         <asp:TextBox Text='<%# Bind("AreaName") %>' runat="server" ID="AreaNameTextBox" CssClass="form-control" /></td> 
       </tr> 
      </InsertItemTemplate> 
</asp:ListView> 

<asp:SqlDataSource runat="server" ID="SqlDataSource3" ConnectionString='<%$ ConnectionStrings:CRMSConnectionString %>' DeleteCommand="DELETE FROM [Area] WHERE [AreaId] = @AreaId" InsertCommand="INSERT INTO [Area] ([AreaName], [CityId], [ProvienceId]) VALUES (@AreaName, @CityId, @ProvienceId)" SelectCommand="SELECT * FROM [Area]" UpdateCommand="UPDATE [Area] SET [AreaName] = @AreaName, [CityId] = @CityId, [ProvienceId] = @ProvienceId WHERE [AreaId] = @AreaId"> 
      <DeleteParameters> 
       <asp:Parameter Name="AreaId" Type="Int32"></asp:Parameter> 
      </DeleteParameters> 
      <InsertParameters> 
       <asp:Parameter Name="AreaName" Type="String"></asp:Parameter> 
       <asp:Parameter Name="CityId" Type="Int32"></asp:Parameter> 
       <asp:Parameter Name="ProvienceId" Type="Int32"></asp:Parameter> 
      </InsertParameters> 
      <UpdateParameters> 
       <asp:Parameter Name="AreaName" Type="String"></asp:Parameter> 
       <asp:Parameter Name="CityId" Type="Int32"></asp:Parameter> 
       <asp:Parameter Name="ProvienceId" Type="Int32"></asp:Parameter> 
       <asp:Parameter Name="AreaId" Type="Int32"></asp:Parameter> 
      </UpdateParameters> 
     </asp:SqlDataSource>