I am fairly new to ASP.NET, but have been rolling right along, able to get past all hurdles thus far, with a little research. But I've got a little issue that I can't seem to get around, involving a custom control I've created.
The control is a little widget that pops-up via JQuery and contains controls for allowing the user to filter on a result set. I had all the elements of this pop-up embedded within two specific pages, and those pages were each working fine. I decided to create a custom control, and have done so correctly, so far as I can tell, using an ascx file with Control' directive and aRegister' directive on the target page, so:
<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="PopUp_TopicFilterControl.ascx.cs" Inherits="POD.PopUp_TopicFilterControl" %>
And
<%@ Register TagPrefix="popup" TagName="TopicFilterControl" Src="~/Controls/PopUp_TopicFilterControl.ascx" %>
The `main' page contains an object datasource which needs to reference controls within my custom control for its select parameters. Here's the datasource:
<asp:ObjectDataSource ID="TopicDataSource" runat="server" SelectMethod="GetRecentTopics" TypeName="POD.App_Objects.Topic">
<SelectParameters>
<asp:Parameter DefaultValue="12" Name="select_limit" Type="Int32" />
<asp:ControlParameter DefaultValue="" ControlID="TopicCategoryFilterList" Name="category" Type="String" />
<asp:ControlParameter DefaultValue="" ControlID="TopicCreatorFilterList" Name="creator" Type="Int32" />
<asp:ControlParameter DefaultValue="" ControlID="TopicDateAfterFilterText" Name="date_after" Type="String" />
<asp:ControlParameter DefaultValue="" ControlID="TopicDateBeforeFilterText" Name="date_before" Type="String" />
</SelectParameters>
</asp:ObjectDataSource>
And here is the body of the custom control:
<asp:Panel id="TopicFilter_Panel" runat="server" CssClass="PopUp" ClientIDMode="Static" EnableTheming="False" EnableViewState="False" ViewStateMode="Disabled">
<asp:Panel runat="server" CssClass="PopUp_Heading">
<h1><a id="TopicFilter_Close" href="#">Close [X]</a></h1>
</asp:Panel>
<asp:Panel runat="server" CssClass="PopUp_Body">
<asp:Table runat="server">
<asp:TableRow runat="server">
<asp:TableCell runat="server" HorizontalAlign="Right">
By Category:
</asp:TableCell>
<asp:TableCell runat="server">
<asp:DropDownList
ID="TopicCategoryFilterList"
runat="server"
DataSourceID="TopicCategoryDataSource"
DataTextField="value"
DataValueField="value"
AppendDataBoundItems="True"
AutoPostBack="False">
<asp:ListItem Selected="True" Value="">— All —</asp:ListItem>
</asp:DropDownList>
</asp:TableCell>
</asp:TableRow>
<asp:TableRow runat="server">
<asp:TableCell runat="server" HorizontalAlign="Right">
By Author:
</asp:TableCell>
<asp:TableCell runat="server">
<asp:DropDownList
ID="TopicCreatorFilterList"
runat="server"
DataSourceID="UserDataSource"
DataTextField="person_name_full"
DataValueField="user_id"
AppendDataBoundItems="True"
AutoPostBack="False">
<asp:ListItem Selected="True" Value="">— All —</asp:ListItem>
</asp:DropDownList>
</asp:TableCell>
</asp:TableRow>
<asp:TableRow runat="server">
<asp:TableCell runat="server" HorizontalAlign="Right">
By Date (After):
</asp:TableCell>
<asp:TableCell runat="server">
<asp:TextBox ID="TopicDateAfterFilterText" runat="server" />
<ajaxToolkit:CalendarExtender ID="TopicDateAfterCalendarExtender" TargetControlID="TopicDateAfterFilterText" PopupPosition="BottomRight" runat="server" />
</asp:TableCell>
</asp:TableRow>
<asp:TableRow runat="server">
<asp:TableCell runat="server" HorizontalAlign="Right">
By Date (Before):
</asp:TableCell>
<asp:TableCell runat="server">
<asp:TextBox ID="TopicDateBeforeFilterText" runat="server" />
<ajaxToolkit:CalendarExtender ID="TopicDateBeforeCalendarExtender" TargetControlID="TopicDateBeforeFilterText" PopupPosition="BottomRight" runat="server" />
</asp:TableCell>
</asp:TableRow>
<asp:TableRow>
<asp:TableCell ColumnSpan="2" VerticalAlign="Bottom" HorizontalAlign="Center">
<asp:Button runat="server" Text="Apply" CssClass="PopUp_Apply" />
</asp:TableCell>
</asp:TableRow>
</asp:Table>
</asp:Panel>
</asp:Panel>
The error I'm getting is simply that the object datasource isn't seeing the controls inside my custom control (e.g., "Could not find control 'TopicCategoryFilterList' in ControlParameter 'category'"). Obviously a very simple matter, but I can't for the life of me seem to simply figure-out how to make this work. I'm quite certain this must've been addressed here, but I cannot find an example.
Here is my own solution to this "issue," in case someone bumps into the same difficulty and spins their wheels as furiously as I did, to find the answer. First, here's a snippet of the code for returning a property of the custom control. I have this code sitting in the ascx.cs file:
public partial class PopUp_TopicFilterControl : System.Web.UI.UserControl
{
public string TopicCategory
{
get { return TopicCategoryFilterList.SelectedValue.ToString(); }
}
}
And here is the change to the ControlParameter inside the ObjectDataSource:
<asp:ControlParameter
DefaultValue=""
ControlID="TopicFilterSelection"
PropertyName="TopicCategory"
Name="category"
Type="String" />
Note that all I've had to do is change the ControlID to the name of my custom control, and add the PropertyName attribute, which refers to the property that I defined in the ascx.cs file.
That's all there is to it. Obvious when you see it, but it had me stumped for quite a few hours.