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POWhy are children of my custom user-control not being initialized?
 

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  1. POWhy are children of my custom user-control not being initialized?
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    <p><strong>UPDATE:</strong> <em>I've been experimenting with my controls some more and I think I've gotten closer. Please read on for updated info.</em></p> <p>I have 2 ASP.NET 2.0 user controls, one of which is placed <em>inside</em> of the other one. Inside of the inner control I have an <code>HtmlAnchor</code> tag control which I'm trying to set a URL for from the outer control. When I attempt to set the <code>HRef</code> property from the rendering page's markup, the <code>HtmlAnchor</code> control is <code>null</code> and throws an exception.</p> <p>The URL <code>set</code> property is being called <em>before</em> the OnInit event of either the inner or the outer control and before the main Page's '<code>OnPreInit</code>' event. I'm assuming this is because I am setting the URL of the child control in the markup of the parent control on the page I'm rendering the controls on which means the value is set before <code>OnInit()</code>. Here is the (stripped down) version of the code I'm using: </p> <pre><code>[ParseChildren(true)]// &lt;- Setting this to false makes the // page render without an exception // but ignores anything in the markup. [PersistChildren(false)] public partial class OuterControl : System.Web.UI.UserControl { // The private '_Inner' control is declared // in the .ascx markup of the control [PersistenceMode(PersistenceMode.InnerProperty)] public InnerControl Inner { get{ return _Inner; } set{ _Inner = value; } } } public partial class InnerControl : System.Web.UI.UserControl { // The private 'linkHref' control is declared // in the .ascx markup of the control public string Url { get { return linkHref.HRef; } set { linkHref.HRef = value; } } } </code></pre> <p>The OuterControl is used on my Default.aspx page like this:</p> <pre><code>&lt;uc1:OuterControl ID="OuterCtrl1" runat="server"&gt; &lt;Inner Url="#" /&gt; &lt;/uc1:OuterControl&gt; </code></pre> <p>In the markup example above, if I try to render this page an exception gets thrown because the <code>linkHref</code> control is null. Using my debugger I can see that every control within the InnerControl is null, but both the InnerControl &amp; OuterControl's <code>OnInit()</code> event has not been triggered yet when the <code>Url</code> property is accessed.</p> <p><strong>UPDATE</strong><br> I thought adding the attributes '<code>ParseChildren</code>' and '<code>PersistChildren</code>' would help. I've used them in Server Controls before but never in User Controls, although the effect seems to be similar. I don't think I'm interpreting the documentation for these two properties correctly, but it can stop exceptions from being thrown. The page markup becomes ignored though.</p> <p>Does anyone know a way to have this work. I don't understand why these controls are getting values set before <code>OnInit()</code>. When I try to set their values using the ASPX markup, the constructor for the <code>InnerControl</code> is being called twice. Once to set the values based on the markup (I'm assuming) and again on <code>OnInit()</code> (which I'm guessing is why the markup values are getting ignored).</p> <p>Is this effort hopeless or am I just approaching it from the wrong angle?</p>
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