Accessing a Custom Configuration Section in .Net

Question

I am trying to access settings in my config file, which is a series of xml elements listed as such:

<databases>
<database name="DatabaseOne" Value="[value]" />
<database name="DatabaseTwo" Value="[value]" />
</databases>

Now I want to access it. I have set up classes like so:

Public Class DatabaseConfigurationHandler
    Inherits ConfigurationSection

    <ConfigurationProperty("Databases", IsDefaultCollection:=True)> _
   Public ReadOnly Property Databases() As DatabaseCollection
        Get
            Return CType(Me("Databases"), DatabaseCollection)
        End Get
    End Property
End Class

Public Class DatabaseCollection
    Inherits ConfigurationElementCollection

    Protected Overloads Overrides Function CreateNewElement() As ConfigurationElement
        Return (New Database())
    End Function

    Protected Overloads Overrides Function GetElementKey(ByVal element As ConfigurationElement) As Object
        Return (CType(element, Database).DatabaseName)
    End Function

End Class

Public Class Database
    Inherits ConfigurationElement

    <ConfigurationProperty("name", IsKey:=True, IsRequired:=True)> _
       Public Property DatabaseName() As String
        Get
            Return Me("name").ToString()
        End Get
        Set(ByVal Value As String)
            Me("name") = Value
        End Set
    End Property


    <ConfigurationProperty("value", IsRequired:=True)> _
Public Property DatabaseValue() As String
        Get
            Return Me("value").ToString()
        End Get
        Set(ByVal Value As String)
            Me("value") = Value
        End Set
    End Property

End Class

I want to be able get the element by it's name and return the value but I can't see to do that:

Dim config As New DatabaseConfigurationHandler
                config = System.Configuration.ConfigurationManager.GetSection("databases/database")
                Return config.Databases("DatabaseOne")

Am I missing some code, what am I doing wrong? Any other errors in the above?

Thanks.

Answer 1

Here's a cut and paste from something very similar I did a few days ago.

Config:

  <ListConfigurations>
    <lists>
      <add Name="blah" EndpointConfigurationName="blah" ListName="blah" ConnectionString="blah" TableName="blah" FieldsCsv="blah" DbFieldsCsv="blah"/>
      <add Name="blah2" EndpointConfigurationName="blah" ListName="blah" ConnectionString="blah" TableName="blah" FieldsCsv="blah" DbFieldsCsv="blah"/>
    </lists>
  </ListConfigurations>

Config section C#:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Configuration;

namespace App
{
    /// <summary>
    /// Individual list configuration
    /// </summary>
    class ListConfiguration : ConfigurationElement
    {
        [ConfigurationProperty("Name", IsKey = true, IsRequired = true)]
        public string Name
        {
            get { return (string)this["Name"]; }
        }

        [ConfigurationProperty("EndpointConfigurationName", IsRequired = true)]
        public string EndpointConfigurationName
        {
            get { return (string)this["EndpointConfigurationName"]; }
        }

        [ConfigurationProperty("ListName", IsRequired = true)]
        public string ListName
        {
            get { return (string)this["ListName"]; }
        }

        [ConfigurationProperty("ConnectionString", IsRequired = true)]
        public string ConnectionString
        {
            get { return (string)this["ConnectionString"]; }
        }

        [ConfigurationProperty("TableName", IsRequired = true)]
        public string TableName
        {
            get { return (string)this["TableName"]; }
        }

        [ConfigurationProperty("FieldsCsv", IsRequired = true)]
        public string FieldsCsv
        {
            get { return (string)this["FieldsCsv"]; }
        }

        [ConfigurationProperty("DbFieldsCsv", IsRequired = true)]
        public string DbFieldsCsv
        {
            get { return (string)this["DbFieldsCsv"]; }
        }
    }

    /// <summary>
    /// Collection of list configs
    /// </summary>
    class ListConfigurationCollection : ConfigurationElementCollection
    {
        protected override ConfigurationElement CreateNewElement()
        {
            return new ListConfiguration();
        }

        protected override object GetElementKey(ConfigurationElement element)
        {
            return ((ListConfiguration)element).Name;
        }
    }

    /// <summary>
    /// Config section
    /// </summary>
    class ListConfigurationSection : ConfigurationSection
    {
        [ConfigurationProperty("lists")]
        public ListConfigurationCollection Lists
        {
            get { return (ListConfigurationCollection)this["lists"]; }
        }
    }
}

And the code to pick it up from the main app:

ListConfigurationSection configSection = null;
try
{
    configSection = ConfigurationManager.GetSection("ListConfigurations") as ListConfigurationSection;
}
catch (System.Configuration.ConfigurationErrorsException)
{
}

Answer 2

There isn't any good reason to design this kind of stuff by hand anymore. Rather, you should be using the Configuration Section Designer on CodePlex:

http://csd.codeplex.com/

Once installed, you can just add a new item to your project (a configuration section designer) and then add the elements and the constraints. I've found it VERY easy to use, and I will probably never write a piece of code for configuration files again.