將參數傳遞給SQLDataSource

Question

我有兩個下拉列表，程度和程序分別，我想根據從度下拉列表中選擇的程度生成程序列表值。我怎麼能做到這一點，代碼如下：

<asp:DropDownList ID="Degree_DList" runat="server" DataSourceID="Degrees_DropdownList" 
DataTextField="DEGREE_NAME" DataValueField="DEGREE_ID" AppendDataBoundItems="True"> 
</asp:DropDownList> 

<asp:SqlDataSource ID="Degrees_DropdownList" runat="server" ConnectionString="<%$ ConnectionStrings:admConnectionString %>" ProviderName="<%$ ConnectionStrings:admConnectionString.ProviderName %>" 
SelectCommand="SELECT DEGREE_ID, DEGREE_NAME FROM DEGREE"> </asp:SqlDataSource> 

<asp:DropDownList ID="Program_Dlist" runat="server" AppendDataBoundItems="True" DataSourceID="Programs_DropdownList" DataTextField="PROGRAM_NAME" DataValueField="PROGRAM_ID"></asp:DropDownList> 

<asp:SqlDataSource ID="Programs_DropdownList" runat="server" ConnectionString="<%$ ConnectionStrings:admConnectionString %>" ProviderName="<%$ ConnectionStrings:admConnectionString.ProviderName %>" 
SelectCommand="SELECT PROGRAM_ID, PROGRAM_NAME FROM PROGRAMS WHERE DEGREE_ID = @DEGREE_ID"><SelectParameters> 
<asp:ControlParameter Name="DEGREE_ID" ControlID="Degree_DList" PropertyName="SelectedValue" /> 
</SelectParameters> 
</asp:SqlDataSource> 

Answer 1

你必須通知您DataSource你提供一些參數在SELECT：

<asp:SqlDataSource ... > 
    <SelectParameters> 
     <asp:Parameter Name="DEGREE_ID" /> 
    </SelectParameters> 
</asp:SqlDataSource> 

不要忘了提供代碼參數：

MyDataSource.SelectParameters["DEGREE_ID"].DefaultValue = "12345";