AJAX ComboBox呈现为TextBox

Question

我有2个组合框的页面。它们都有不相关的数据集，所以级联组合框似乎没有意义。当页面呈现组合框A很好时，B呈现为文本框。如果我禁用组合框A，那么B将正确渲染。

以下是我的定义（每个组合框都在自己的面板中）。

<asp:ComboBox ID="cboRequestType" runat="server" CssClass="comboBoxes" 
    DropDownStyle="DropDownList" ItemInsertLocation="Append" AutoPostBack="True"
    AppendDataBoundItems="True" onselectedindexchanged="cboRequestType_SelectedIndexChanged">
    <asp:ListItem Selected="True" Text="Select Request Type..." Value="Select Request Type" />
</asp:ComboBox>

<asp:ComboBox ID="cboContactName" runat="server" CssClass="comboBoxes" 
    DropDownStyle="DropDownList" ItemInsertLocation="Append" AutoPostBack="True"
    AppendDataBoundItems="True" onselectedindexchanged="cboContactName_SelectedIndexChanged">
</asp:ComboBox>

以下是完整的细分和对测试用例的更好描述。

1. 当页面加载两个组合框时cboContactName呈现为txtbox。
2. 如果我发送了pnlRequestType.visible = false，那么cboContactName会正确呈现。

3. 将cboRequestType更改为元素允许cboContactName呈现为组合者。

   <asp:Panel ID="pnlRequestType" runat="server">
       <asp:Label ID="lblRequestType" Text="Request Type" runat="server"
           CssClass="comboBoxLabel" />
       <asp:ComboBox ID="cboRequestType" runat="server" CssClass="comboBoxes" 
           DropDownStyle="DropDownList" ItemInsertLocation="Append" AutoPostBack="True"
           AppendDataBoundItems="True" onselectedindexchanged="cboRequestType_SelectedIndexChanged">
           <asp:ListItem Selected="True" Text="Select Request Type..." Value="Select Request Type" />
       </asp:ComboBox>     
       <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" 
           ErrorMessage="Select A Catagory." CssClass="fieldValidationMessage" 
           ControlToValidate="cboRequestType" InitialValue="Select Request Type" >
       </asp:RequiredFieldValidator>
   </asp:Panel>
   
   <asp:Panel ID="pnlContact" runat="server">
       <asp:Label ID="lblContactName" Text="Contact" runat="server"    
           AssociatedControlID="cboContactName" CssClass="comboBoxLabel" />
       <asp:ComboBox ID="cboContactName" runat="server" CssClass="comboBoxes" 
           DropDownStyle="DropDownList" ItemInsertLocation="Append" AutoPostBack="True"
           AppendDataBoundItems="True" onselectedindexchanged="cboContactName_SelectedIndexChanged">
       </asp:ComboBox>
   </asp:Panel>