Asp.net 我的dropdownlist没有显示我的硬编码列表项

我有四个dropdownlists，都依赖于它前面的一个，使用ControlParameters和AutoPostBack=“true”，它们都工作得很好——除了最后一个。出于某种原因，forth没有显示我的硬编码--All--“项，我需要它，这样用户就可以选择查看所有项，或者根据所选值限制项。任何建议都将不胜感激

1（总是显示所有不同的值，加上“-all--”选项）：

 <!-- Division (gt_division) -->
 <asp:DropDownList runat="server" ID="DDLDivision" DataSourceID="DSDivision" DataValueField="gt_division" DataTextField="gt_division" AppendDataBoundItems="true" AutoPostBack="true">
                 <asp:ListItem Text="--All--" Value="" />
            </asp:DropDownList>
            <asp:SqlDataSource ID="DSDivision" ConnectionString="<%$ ConnectionStrings:CDRConnectionString %>" runat="server" SelectCommand="select distinct gt_division from chg_dtl">
            </asp:SqlDataSource>

 <!-- Physician (BILLING_NAME) -->
 <asp:DropDownList runat="server" ID="DDLPhysician" DataSourceID="DSPhysician" DataValueField="billing_prov_name" DataTextField="billing_name" AppendDataBoundItem="true" AutoPostBack="true">
                <asp:ListItem Text="All" Value="" />
            </asp:DropDownList>
            <asp:SqlDataSource ID="DSPhysician" ConnectionString="<%$ ConnectionStrings:CDRConnectionString %>" runat="server"
                SelectCommand="SELECT distinct billing_name 
                               FROM chg_dtl 
                               WHERE gt_division = @gt_division AND bill_area = @bill_area AND pos_name = @pos_name"
                >
                <SelectParameters>
                    <asp:ControlParameter Name="gt_division" ControlID="DDLDivision" PropertyName="SelectedValue" />
                    <asp:ControlParameter Name="bill_area" ControlID="DDLProgram" PropertyName="SelectedValue" />
                    <asp:ControlParameter Name="pos_name" ControlID="DDLLocation" PropertyName="SelectedValue" />
                </SelectParameters>
            </asp:SqlDataSource>

2（工作正常，下拉列表显示“--All--”，加上基于第一个下拉列表中的选择的不同值（controlparameter gt_部分）：

 <!-- Program (bill_area) -->
 <asp:DropDownList runat="server" ID="DDLProgram" DataSourceID="DSProgram" DataValueField="bill_area" DataTextField="bill_area" AppendDataBoundItems="true" AutoPostBack="true">
                <asp:ListItem Text="--All--" Value="" />
            </asp:DropDownList>
            <asp:SqlDataSource ID="DSProgram" ConnectionString="<%$ ConnectionStrings:CDRConnectionString %>" runat="server" SelectCommand="SELECT distinct bill_area FROM chg_dtl WHERE gt_division = @gt_division">
                <SelectParameters>
                    <asp:ControlParameter Name="gt_division" ControlID="DDLDivision" PropertyName="SelectedValue"/>
                </SelectParameters>
            </asp:SqlDataSource>

<!-- Location (pos_name) -->
<asp:DropDownList runat="server" ID="DDLLocation" DataSourceID="DSLocation" DataValueField="pos_name" DataTextField="pos_name" AppendDataBoundItems="true" AutoPostBack="true">
                <asp:ListItem Text="--All--" Value="" />
            </asp:DropDownList>
            <asp:SqlDataSource ID="DSLocation" ConnectionString="<%$ ConnectionStrings:CDRConnectionString %>" runat="server" SelectCommand="SELECT distinct pos_name FROM chg_dtl WHERE gt_division = @gt_division and bill_area = @bill_area"
                >
                <SelectParameters>
                    <asp:ControlParameter Name="gt_division" ControlID="DDLDivision" PropertyName="SelectedValue" />
                    <asp:ControlParameter Name="bill_area" ControlID="DDLProgram" PropertyName="SelectedValue" />
                </SelectParameters>
            </asp:SqlDataSource>

3（也可以正常工作，显示“--All--”加上基于前两个下拉列表的值）：

 <!-- Program (bill_area) -->
 <asp:DropDownList runat="server" ID="DDLProgram" DataSourceID="DSProgram" DataValueField="bill_area" DataTextField="bill_area" AppendDataBoundItems="true" AutoPostBack="true">
                <asp:ListItem Text="--All--" Value="" />
            </asp:DropDownList>
            <asp:SqlDataSource ID="DSProgram" ConnectionString="<%$ ConnectionStrings:CDRConnectionString %>" runat="server" SelectCommand="SELECT distinct bill_area FROM chg_dtl WHERE gt_division = @gt_division">
                <SelectParameters>
                    <asp:ControlParameter Name="gt_division" ControlID="DDLDivision" PropertyName="SelectedValue"/>
                </SelectParameters>
            </asp:SqlDataSource>

<!-- Location (pos_name) -->
<asp:DropDownList runat="server" ID="DDLLocation" DataSourceID="DSLocation" DataValueField="pos_name" DataTextField="pos_name" AppendDataBoundItems="true" AutoPostBack="true">
                <asp:ListItem Text="--All--" Value="" />
            </asp:DropDownList>
            <asp:SqlDataSource ID="DSLocation" ConnectionString="<%$ ConnectionStrings:CDRConnectionString %>" runat="server" SelectCommand="SELECT distinct pos_name FROM chg_dtl WHERE gt_division = @gt_division and bill_area = @bill_area"
                >
                <SelectParameters>
                    <asp:ControlParameter Name="gt_division" ControlID="DDLDivision" PropertyName="SelectedValue" />
                    <asp:ControlParameter Name="bill_area" ControlID="DDLProgram" PropertyName="SelectedValue" />
                </SelectParameters>
            </asp:SqlDataSource>

4（显示正确的不同值（基于前三个下拉列表）但是在上一个下拉列表的回发上没有显示“--All--”选项。所以我选择了Program，这个下拉列表填充了正确的不同值，但是缺少“--All--”选项。我需要这个选项为用户提供查看全部的选项，而不仅仅是单个下拉选择的结果。我可能可以在代码中做一些事情ind，但希望所有下拉列表保持不变。）：

 <!-- Division (gt_division) -->
 <asp:DropDownList runat="server" ID="DDLDivision" DataSourceID="DSDivision" DataValueField="gt_division" DataTextField="gt_division" AppendDataBoundItems="true" AutoPostBack="true">
                 <asp:ListItem Text="--All--" Value="" />
            </asp:DropDownList>
            <asp:SqlDataSource ID="DSDivision" ConnectionString="<%$ ConnectionStrings:CDRConnectionString %>" runat="server" SelectCommand="select distinct gt_division from chg_dtl">
            </asp:SqlDataSource>

 <!-- Physician (BILLING_NAME) -->
 <asp:DropDownList runat="server" ID="DDLPhysician" DataSourceID="DSPhysician" DataValueField="billing_prov_name" DataTextField="billing_name" AppendDataBoundItem="true" AutoPostBack="true">
                <asp:ListItem Text="All" Value="" />
            </asp:DropDownList>
            <asp:SqlDataSource ID="DSPhysician" ConnectionString="<%$ ConnectionStrings:CDRConnectionString %>" runat="server"
                SelectCommand="SELECT distinct billing_name 
                               FROM chg_dtl 
                               WHERE gt_division = @gt_division AND bill_area = @bill_area AND pos_name = @pos_name"
                >
                <SelectParameters>
                    <asp:ControlParameter Name="gt_division" ControlID="DDLDivision" PropertyName="SelectedValue" />
                    <asp:ControlParameter Name="bill_area" ControlID="DDLProgram" PropertyName="SelectedValue" />
                    <asp:ControlParameter Name="pos_name" ControlID="DDLLocation" PropertyName="SelectedValue" />
                </SelectParameters>
            </asp:SqlDataSource>

您在第四个下拉列表中使用了“AppendDataBoundItem”而不是“AppendDataBoundItems”

啊！两天来，我一直认为这是一个奇怪的asp回发问题。谢谢！！！我们都去过：）。很高兴我能帮忙。