templatefield中的下拉列表 - 更新失敗（空值插入）

Question

我有一個gridview。在這個我有一個DropDownList的Templatefield（在EditItemTemplate模式下的DDL，在ItemTemplate模式下的標籤）。 當我點擊detailsview的行的編輯時，我可以從DDL中選擇任何值（DDL從sqldatasource填充），但如果我嘗試執行更新，它會失敗，因爲它認爲我沒有提供數據...

這裏是確切的錯誤（DB拒絕NULL數據）：

無法將NULL值插入列 '狀態'，表 'gyumolcs.dbo.orders';列不允許有空值。更新失敗。 聲明已被終止。

這裏是爲GridView的代碼：

<!-- language: c# --> 
<asp:SqlDataSource ID="orderadminSqlDataSource" runat="server" 
    ConnectionString="<%$ ConnectionStrings:dotnetConnectionString %>" 
    SelectCommand="SELECT orders.ID, aspnet_Users.UserName, orders.quantity AS Quantity, product.name AS Product, status.name AS Status, orders.date AS Date FROM orders INNER JOIN product ON orders.ordertype = product.ID INNER JOIN status ON orders.status = status.ID INNER JOIN aspnet_Users ON orders.userid = aspnet_Users.UserId ORDER BY date" 
    DeleteCommand="DELETE FROM orders WHERE (ID = @ID)" 
    UpdateCommand="UPDATE orders SET status = @status WHERE (ID = @ID)"> 
    <DeleteParameters> 
     <asp:Parameter Name="ID" /> 
    </DeleteParameters> 
    <UpdateParameters> 
     <asp:Parameter Name="status" /> 
     <asp:Parameter Name="ID" /> 
    </UpdateParameters> 
</asp:SqlDataSource><asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" 
     DataSourceID="orderadminSqlDataSource" DataKeyNames="ID" Width="608px" 
     AllowPaging="True" AllowSorting="True" PageSize="15"> 
     <Columns> 
      <asp:CommandField ShowDeleteButton="True" ShowEditButton="True" /> 
      <asp:BoundField DataField="ID" HeaderText="ID" 
       SortExpression="ID" InsertVisible="False" ReadOnly="True" > 
      <ItemStyle HorizontalAlign="Right" /> 
      </asp:BoundField> 
      <asp:BoundField DataField="UserName" HeaderText="Felhasználónév" 
       SortExpression="UserName" > 
      <HeaderStyle HorizontalAlign="Center" /> 
      <ItemStyle HorizontalAlign="Center" /> 
      </asp:BoundField> 
      <asp:BoundField DataField="Quantity" HeaderText="Mennyiség (kg)" 
       SortExpression="Quantity" > 
      <HeaderStyle HorizontalAlign="Center" /> 
      <ItemStyle HorizontalAlign="Center" /> 
      </asp:BoundField> 
      <asp:BoundField DataField="Product" HeaderText="Termék" 
       SortExpression="Product" > 
      <HeaderStyle HorizontalAlign="Center" /> 
      <ItemStyle HorizontalAlign="Center" /> 
      </asp:BoundField> 
      <asp:TemplateField HeaderText="Rendelés státusz" SortExpression="status"> 
       <EditItemTemplate> 
        <!--<asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("Status") %>'></asp:TextBox>--> 

        <asp:DropDownList ID="DropDownList1" runat="server" 
         DataSourceID="statustypeDDLSqlDataSource" DataTextField="name" 
         DataValueField="ID"> 
        </asp:DropDownList> 
        <asp:SqlDataSource ID="statustypeDDLSqlDataSource" runat="server" 
         ConnectionString="<%$ ConnectionStrings:dotnetConnectionString %>" 
         SelectCommand="SELECT [ID], [name] FROM [status]"> 
        </asp:SqlDataSource> 

       </EditItemTemplate> 
       <ItemTemplate> 
        <asp:Label ID="status" runat="server" Text='<%# Bind("Status") %>'></asp:Label> 
       </ItemTemplate> 
       <HeaderStyle HorizontalAlign="Center" /> 
       <ItemStyle HorizontalAlign="Center" /> 
      </asp:TemplateField> 
      <asp:BoundField DataField="Date" HeaderText="Dátum" SortExpression="Date" /> 
     </Columns> 
     <PagerSettings PageButtonCount="15" Mode="NumericFirstLast" /> 
    </asp:GridView> 

這裏是orderadminSqlDataSource的代碼（GridView的數據源）

<!-- language: c# --> 
    <asp:SqlDataSource ID="orderadminSqlDataSource" runat="server" 
     ConnectionString="<%$ ConnectionStrings:dotnetConnectionString %>" 
     SelectCommand="SELECT orders.ID, aspnet_Users.UserName, orders.quantity AS Quantity, product.name AS Product, status.name AS Status, orders.date AS Date FROM orders INNER JOIN product ON orders.ordertype = product.ID INNER JOIN status ON orders.status = status.ID INNER JOIN aspnet_Users ON orders.userid = aspnet_Users.UserId ORDER BY date" 
     DeleteCommand="DELETE FROM orders WHERE (ID = @ID)" 
     UpdateCommand="UPDATE orders SET status = @status WHERE (ID = @ID)"> 
     <DeleteParameters> 
      <asp:Parameter Name="ID" /> 
     </DeleteParameters> 
     <UpdateParameters> 
      <asp:Parameter Name="status" /> 
      <asp:Parameter Name="ID" /> 
     </UpdateParameters> 
    </asp:SqlDataSource> 

請幫助我，我想不通的問題。 在此先感謝！

Answer 1

我想你忘記設置下拉的SelectedValue屬性：

<asp:DropDownList ID="DropDownList1" 
        runat="server" 
        DataSourceID="statustypeDDLSqlDataSource" 
        DataTextField="name" 
        DataValueField="status" 
        SelectedValue='<%# Bind("status") %>' 
        AppendDataBoundItems="True" > 

更改代碼statustypeDDLSqlDataSource：

<asp:SqlDataSource ID="statustypeDDLSqlDataSource" runat="server" 
        ConnectionString="<%$ ConnectionStrings:dotnetConnectionString %>" 
        SelectCommand="SELECT [ID] as status, [name] FROM [status]"> 
</asp:SqlDataSource> 

您也可以簡化（無需括號）這樣的：

UPDATE orders SET [status] = @status WHERE [ID] = @ID 

注意：我不得不重命名曲線中的ID列紅黴素，使其與status參數符合你定義如下：

<UpdateParameters> 
    <asp:Parameter Name="status" /> 
    <asp:Parameter Name="ID" /> 
</UpdateParameters> 

我最後的編輯，並嘗試在這裏：d

後仔細看你的GridView的SELECT聲明我看到那裏的錯誤在於：

SELECT orders.ID, 
     aspnet_Users.UserName, 
     orders.quantity AS Quantity, 
     product.name AS Product, 
     status.name AS Status, 
     orders.date AS Date 
FROM orders 
INNER JOIN product ON 
orders.ordertype = product.ID 
INNER JOIN status ON orders.status = status.ID 
INNER JOIN aspnet_Users ON orders.userid = aspnet_Users.UserId 
ORDER BY date 

將其更改爲：

SELECT orders.ID, 
     aspnet_Users.UserName, 
     orders.quantity AS Quantity, 
     product.name AS Product, 
     status.ID AS status, 
     status.name AS StatusName, 
     orders.date AS Date 
FROM orders 
INNER JOIN product ON 
orders.ordertype = product.ID 
INNER JOIN status ON orders.status = status.ID 
INNER JOIN aspnet_Users ON orders.userid = aspnet_Users.UserId 
ORDER BY date 

現在你必須得改變這種部分：

<ItemTemplate> 
<asp:Label ID="status" runat="server" Text='<%# Bind("StatusName") %>'></asp:Label> 
</ItemTemplate> 

---

順便說...這裏是一個不錯的教程一步一步在這個問題上：

Walkthrough: Displaying a Drop-Down List While Editing in the GridView Web Server Control