C# ConfigurationManager.GetSection could not load file or assembly

Question

I am stuck! this seems really daft but I can not see where I am going wrong. I am creating a 2.0 C# ASP.NET website. I am trying to use a custom section in the web.config file with:

DatabaseFactorySectionHandler sectionHandler = ConfigurationManager.GetSection("DatabaseFactoryConfiguration") as DatabaseFactorySectionHandler;

I have a separate DLL for the Objects which are in Bailey.DataLayer namespace. But when I run the test.aspx page I get the following error:

System.Configuration.ConfigurationErrorsException was unhandled by user code

Message="An error occurred creating the configuration section handler for DatabaseFactoryConfiguration: Could not load file or assembly 'Bailey.DataLayer' or one of its dependencies. The system cannot find the file specified. (C:\\Documents and Settings\\Administrator.PIP\\My Documents\\Visual Studio 2005\\WebSites\\bailey\\web.config line 13)"
Source="System.Configuration"

The class that I am trying to get is as follows:

namespace Bailey.DataLayer
{
    public sealed class DatabaseFactorySectionHandler : ConfigurationSection
    {
        [ConfigurationProperty("Name")]
        public string Name
        {
            get { return (string)base["Name"]; }
        }

        [ConfigurationProperty("ConnectionStringName")]
        public string ConnectionStringName
        {
            get { return (string)base["ConnectionStringName"]; }
        }

        public string ConnectionString
        {
            get
            {
                try
                {
                    return ConfigurationManager.ConnectionStrings[ConnectionStringName].ConnectionString;
                }
                catch (Exception excep)
                {
                    throw new Exception("Connection string " + ConnectionStringName +
                                        " was not found in web.config. " + 
                                        excep.Message);
                }
            }
        }
    }
}

The web config file has this section:

<configSections>
  <section name="DatabaseFactoryConfiguration" 
           type="Bailey.DataLayer.DatabaseFactorySectionHandler, Bailey.DataLayer" />
</configSections>

I have done this in a console app without a problem but can not see any differences apart from it being in a web page.

EDIT

It all compiles and throws the error at runtime so I can only assume it find the assembly because it is referenced in the test.aspx.cs page.

I have the following using statement at the top of the test.aspx.cs page:

using Bailey.DataLayer;

Here is the whole web.config file so there is no confusion:

<configuration>
   <configSections>
      <section name="DatabaseFactoryConfiguration" type="Bailey.DataLayer.DatabaseFactorySectionHandler, Bailey.DataLayer" />
   </configSections>
    <appSettings/>
   <connectionStrings>
      <add name="BaileyMDFConString" connectionString="Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\bailey.mdf;Integrated Security=True;User Instance=True"  providerName="System.Data.SqlClient" />
    </connectionStrings>
     <DatabaseFactoryConfiguration Name="System.Data.SqlClient" ConnectionStringName="BaileyMDFConString" />
   <system.web>         
      <compilation debug="true"/>       
      <authentication mode="Windows"/>  
   </system.web>
</configuration>

Answer 1

Either you're using the wrong name (i.e. it's not called Bailey.DataLayer.dll), or it's not being copied to the bin directory on build. This last one doesn't seem likely however.

(See my comments on the question for clarification).