Hello!
I'm trying to re-use my ASP User Controls in other projects, and have hit upon a problem. I've read ScottGu's post on http://weblogs.asp.net/scottgu/archive/2005/08/28/423888.aspx and tried to follow his patterns but run-time the child controls of my controls are not being initialised.
My setup: I'm using Visual Studio 2008 I've created a solution to hold the controls I want to distribute to several other solutions. This solution contains:
- library projects (for model code, etc.), let's call this "ClassLibrary"
- a WebApp project (with my User Controls), let's call this "Innermost"
- a number of other WebApp projects acting as Shells for the Innermost project, let's regard one of them and call it "Outer"
The thought behind this is that Innermost contains the functionality and Outer contains any special modifications needed to make Innermost -controls work in a particular framework.
The ClassLibrary has code like this (this is all from a demo-setup I made to make sure it was an ASP issue, not something else I was doing):
using System;
namespace ClassLibrary {
public class LibraryClass {
public long getLong() {
return DateTime.Now.Ticks;
}
public string getString() {
return DateTime.Now.ToString();
}
}
}
Innermost references the library project and works fine. This is an example of a UserControl in this project:
<%@ Control Language="C#" AutoEventWireup="true"
CodeBehind="WebUserControl1.ascx.cs"
Inherits="Innermost.UserControls.WebUserControl1" %>
<asp:Label ID="testLabel" runat="server"/>
with code-behind:
using System;
using System.Web.UI;
using ClassLibrary;
namespace Innermost.UserControls {
public partial class WebUserControl1 : UserControl {
protected void Page_Load(object sender, EventArgs e) {
LibraryClass c = new LibraryClass();
testLabel.Text = "Your number is " + c.getLong();
}
}
}
I have a test page in the Innermost project which uses the User Controls of the Innermost project by registering them with the following syntax:
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Test1.aspx.cs"
Inherits="Innermost.Test1" %>
<%@ Register TagPrefix="inner" TagName="Control1"
Src="~/UserControls/WebUserControl1.ascx" %>
<%@ Register TagPrefix="inner" TagName="Control2"
Src="~/UserControls/WebUserControl2.ascx" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
Control 1:
<inner:Control1 ID="control1" runat="server" />
<br />
Control 2:
<inner:Control2 ID="control2" runat="server" />
</div>
</form>
</body>
</html>
The Outer project references Innermost and ClassLibrary; and contains UserControls with the following registering of the Innermost controls:
<%@ Control Language="C#" AutoEventWireup="true"
CodeBehind="TopControl.ascx.cs" Inherits="Outer.Control.TopControl" %>
<%@ Register TagPrefix="inner" Assembly="Innermost"
Namespace="Innermost.UserControls" %>
<inner:WebUserControl1 ID="Control1" runat="server"/>
<inner:WebUserControl2 ID="Control2" runat="server"/>
With a simple code-behind: using System; using System.Web.UI;
namespace Outer.Control {
public partial class TopControl : UserControl {
public bool ShowType1 { get; set; }
protected void Page_Load(object sender, EventArgs e) {
Control1.Visible = ShowType1;
Control2.Visible = !ShowType1;
}
}
}
When I run the test-page in the Innermost project I get no errors, and everything works. When I run the Outer project I get NullReferenceExceptions telling me that the child controls of the Innermost.UserControls.WebUserControlX have not been set.
StackTrace:
[NullReferenceException: Object reference not set to an instance of an object.]
Innermost.UserControls.WebUserControl1.Page_Load(Object sender, EventArgs e) in c:\Test\ASP\Innermost\Innermost\UserControls\WebUserControl1.ascx.cs:9
System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14
System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35
System.Web.UI.Control.OnLoad(EventArgs e) +99
System.Web.UI.Control.LoadRecursive() +50
System.Web.UI.Control.LoadRecursive() +141
System.Web.UI.Control.LoadRecursive() +141
System.Web.UI.Control.LoadRecursive() +141
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627
I can provide the test setup as solutions if anyone wants to have a closer look at this.
So, finally, my question is: Why do the ChildControls of the controls not get set up as expected? Even if I run CreateChildControls() in the Init of the outer controls they aren't being created. Is there some particular way I need to compile the Innermost project for use in the Outer project?
Any help would be much appreciated!