在 asp.net detailsview 模板化控件中实现级联 DropDownList 绑定

Question

我在 asp.net 详细视图“PlantingHatchery”和“CatalogNames”中有两个下拉列表。第一个的结果决定了第二个的值。第一个填充得很好，但不是第二个。我已经尝试了几个建议，但没有一个对我有用。我哪里错了？

下面是相关代码：

 <asp:DetailsView ID="dvSMasterCurrentYear" runat="server" AutoGenerateRows="False" align="center" DataKeyNames="SMasterid" DataSourceID="SqlDataSource1" 
        Height="50px" Width="437px" AutoGenerateInsertButton="True" AllowPaging="True" insertcommand =" Insert Into [SMasterCurrentYear}
        ([HatcheryCodePlant],[CatalogNo],[DataPlant],[TimePlant],[SpeciesCode],[BroodYear],[SizeCode],[MethodCode],[Length], [PoundFish],[NumberPlanted],[NumberPerLB],[HaulMort],
        [License], [ActSites], [HatcheryCodeRear],[Comments],[H20Temp],[ConsOfficer],[TankTemp],[Marks],[Raceway])
        Values (@HatcheryCodePlant, @CatalogNum, @DataPlant, @TimePlant, @SpeciesCode, @BroodYear, @SizeCode, @MethodCode, @Length, @PoundFish, @NumberPlanted, @NumberPerLB, 
        @HaulMort, @License, @ActSites, @HatcheryCodeRear, @Comments, @H20Temp, @ConsOfficer, @TankTemp, @Marks, @Raceway) " Font-Bold="True" BackColor="#FFCC99" Font-Size="Medium" DefaultMode="Insert">
        <AlternatingRowStyle BackColor="#99FFCC" />

enter code here

              <asp:TemplateField HeaderText="Planting Hatchery">
                    <ItemTemplate>
                        <asp:Label ID="lblPlantHatch" runat="server" Text='<%# Eval("HatcheryCodePlant")%>' Visible = "true"></asp:Label>
                    </ItemTemplate>
                   <insertItemTemplate>
                        <asp:DropDownList ID="ddPlantingHatchery" runat="server" DataSource='<%# GetPlantingHatchery()%>' 
                        DataTextField="HatcheryNamePlant" DataValueField="HatcheryCodePlant" width= "150" AppendDataBoundItems="true"> 
                       <asp:ListItem Text="Select" Value="" />
                    </asp:DropDownList>
                 </insertItemTemplate>
<asp:TemplateField HeaderText="Water Body Name">
                   <ItemTemplate>
                    <asp:Label ID="lblStreamName" runat="server" Text='<%# Eval("CatalogNo")%>' Visible = "true"></asp:Label>
                </ItemTemplate>
                 <insertItemTemplate>
                    <asp:DropDownList ID="ddCatalogName" runat="server" DataSource='<%# GetCatalogNames()%>' 
                        DataTextField="StreamName" DataValueField="CatalogNo" AppendDataBoundItems="true"> 
                       <asp:ListItem Text="Select" Value="" />
                    </asp:DropDownList>
                       <asp:ObjectDataSource ID="dsWaterBody" runat="server" TypeName="StreamName"
                        SelectMethod="GetCatalogNames">
                        <SelectParameters>
                            <%--<asp:Parameter Name="HatcheryCodetName"  Type="string" />--%>
                            <asp:ControlParameter Name="HatcheryCodePlant" Type="Int32" ControlID="ddPlantingHatchery" PropertyName="SelectedValue"/>
                        </SelectParameters>
                    </asp:ObjectDataSource>
                </insertItemTemplate>enter code here

代码背后：

Private Sub DetailsView1_ItemInserting(sender As Object, e As DetailsViewInsertEventArgs) 处理 dvSMasterCurrentYear.ItemInserting

Dim ddPlantHatch As DropDownList = TryCast(view.FindControl("ddPlantingHatchery"), DropDownList) e.Values.Add("HatcheryCodePlant", ddPlantHatch.SelectedValue)

Dim ddCatNum As DropDownList = TryCast(view.FindControl("ddCatalogName"), DropDownList) e.Values("HatcheryCodePlant") = DirectCast(DirectCast(sender, DetailsView).FindControl("ddPlantingHatchery"), DropDownList).SelectedValue

谢谢

Answer 1

如果您的 GetCatalogNames 方法工作正常，您可能需要做的就是将 autopostback="true" 添加到您的第一个下拉列表中。

此外，您的代码隐藏方法在 ItemInserting 期间触发，这是本例中的默认值。但你可能不需要它。

如果这不起作用，您应该将您的方法设置为触发您的第一个下拉菜单的OnSelectedIndexChanged。为此：

将此添加到您的第一个下拉列表中：

    <asp:DropDownList ID="ddPlantingHatchery" runat="server" DataSource='<%# GetPlantingHatchery()%>' 
                    DataTextField="HatcheryNamePlant" DataValueField="HatcheryCodePlant" width= "150" AppendDataBoundItems="true" AutoPostBack="true" OnSelectedIndexChanged="ddPlantingHatchery_indexchanged"> 
                   <asp:ListItem Text="Select" Value="" />
                </asp:DropDownList>

然后将此方法添加到 CodeBehind：

Public Sub ddPlantingHatchery_indexchanged(sender As Object, e As EventArgs)
    Dim ddCatNum As DropDownList = TryCast(dvSMasterCurrentYear.FindControl("ddCatalogName"), DropDownList)
    ddCatNum.SelectedValue = TryCast(dvSMasterCurrentYear.FindControl("ddPlantingHatchery"), DropDownList).SelectedValue
End Sub

此示例方法将简单地将 ddCatNum 的 SelectedValue 设置为 ddPlant 的 SelectedValue。当然，您可以将其更改为获取您在 ObjectDataSource 方法中定义的值。

另一种方法：将autopostback="true" 添加到您的第一个下拉列表中，然后更改您的 GetCatalognames() 函数以根据回发返回不同的值，如下所示：

    Public Function GetCatalogNames() As DataSet
    If Page.IsPostBack Then
        Dim ddPlantHatch As DropDownList = TryCast(dvSMasterCurrentYear.FindControl("ddPlantingHatchery"), DropDownList)

        Dim myConnection As New SqlConnection(ConnectionString)
        Dim ad As New SqlDataAdapter("SELECT StreamName, CatalogNo, " _
                                      + "HatcheryNamePlant, HatcheryCodePlant, " _
                                      + "LLID FROM vwStockingWatersByHatchery " _
                                      + "where HatcherCodePlant = " + ddPlantHatch.SelectedValue _
                                      + " Order By StreamName", myConnection)
        Dim dsWaterBody As New DataSet()
        ad.Fill(dsWaterBody, "Catalog")
        Return dsWaterBody
    Else


        Dim myConnection As New SqlConnection(ConnectionString)
        Dim ad As New SqlDataAdapter("SELECT StreamName, CatalogNo, " _
                           + "HatcheryNamePlant, HatcheryCodePlant, " _
                           + "LLID FROM vwStockingWatersByHatchery " _

                           + "Order By StreamName", myConnection)
        Dim dsWaterBody As New DataSet()
        ad.Fill(dsWaterBody, "Catalog")
        Return dsWaterBody
    End If


End Function

希望对你有帮助