ASP.NET Custom Control - Unknown server tag

Question

I've made a custom control that inherits from a Literal control. When I try and use my control on a page a parsing error is thrown. I've added this to my web.config

<configuration>   <system.web>     <pages>       <controls>         <add tagPrefix="one" namespace="myApplication.Controls"/>       </controls>     </pages>   </system.web> </configuration> 

And I've added this to my page

<%@ register namespace="myApplication.Controls" tagprefix="one" %> 

Neither of these have fixed the issue. I have a external assembly with some custom controls that work just fine within my project. As a workaround, I'm considering moving my custom control into the external library if there's no simple solution.

--edit

Here's the page code.

<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="SignUp.ascx.cs" Inherits="myApplication.Controls.SignUp" %> <%@ register namespace="myApplication.Controls" tagprefix="one" %> <div class="in">     <span>               <one:resourceliteral id="lblFirstname" runat="server" resourcekey="FirstName" resourceresolver="ResourceStringResolver.GetResourceString">         </one:resourceliteral>               </span>     <div>         <pl:textbox id="txtFirstName" runat="server"></pl:textbox>     </div> </div> 

And here's the code for my actual control

namespace myApplication.Controls {     public class ResourceLiteral : Literal     {         private ResourceManager rm;          public delegate string dResourceResolver( string label, eLanguage language );          public event dResourceResolver ResourceResolver;          public string ResourceKey { get; set; }         public object DataSource { get; set; }          private eLanguage _Language = eLanguage.ENUS;         public eLanguage Language         {             get { return _Language; }             set { _Language = value; }         }          protected override void OnLoad(EventArgs e)         {             base.OnLoad(e);              if (ResourceResolver != null)                 Text = ResourceResolver.Invoke( ResourceKey, _Language );             else             {                 if(rm != null)                 {                     Text = rm.GetString( ResourceKey );                 }             }         }          public void LoadDataSource(string resource)         {             rm = new ResourceManager( resource, Assembly.GetExecutingAssembly() );         }          public void LoadDataSource(Type resource)         {             rm = new ResourceManager( resource );         }     } } 

Answer 1

When adding a namespace, I've found I also need the assembly. If your assembly is also myApplication do this in web.config:

<add tagPrefix="one" namespace="myApplication.Controls" assembly="myApplication"/> 

Then, just clean and rebuild and it should all work. Once this is in your web.config, you don't need to add it to your page unless you're using this in a control in the same directory, then you'll need the reference at the top of the web form. But, I recommend against using custom server controls in the same directory as user controls.