Question

I am trying to implement a custom configuration section in a project and I keep running up against exceptions that I do not understand. I am hoping someone can fill in the blanks here.

I have App.config that looks like this:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <configSections>
        <section name="ServicesSection" type="RT.Core.Config.ServicesConfigurationSectionHandler, RT.Core"/>
    </configSections>
    <ServicesSection type="RT.Core.Config.ServicesSection, RT.Core">
            <Services>
                <AddService Port="6996" ReportType="File" />
                <AddService Port="7001" ReportType="Other" />
            </Services>
        </ServicesSection>
</configuration>

I have a ServiceConfig element defined like so:

public class ServiceConfig : ConfigurationElement
  {
    public ServiceConfig() {}

    public ServiceConfig(int port, string reportType)
    {
      Port = port;
      ReportType = reportType;
    }

    [ConfigurationProperty("Port", DefaultValue = 0, IsRequired = true, IsKey = true)]
    public int Port 
    {
      get { return (int) this["Port"]; }
      set { this["Port"] = value; }
    }

    [ConfigurationProperty("ReportType", DefaultValue = "File", IsRequired = true, IsKey = false)]
    public string ReportType
    {
      get { return (string) this["ReportType"]; }
      set { this["ReportType"] = value; }
    }
  }

And I have a ServiceCollection defined like so:

public class ServiceCollection : ConfigurationElementCollection
  {
    public ServiceCollection()
    {
      Console.WriteLine("ServiceCollection Constructor");
    }

    public ServiceConfig this[int index]
    {
      get { return (ServiceConfig)BaseGet(index); }
      set
      {
        if (BaseGet(index) != null)
        {
          BaseRemoveAt(index);
        }
        BaseAdd(index, value);
      }
    }

    public void Add(ServiceConfig serviceConfig)
    {
      BaseAdd(serviceConfig);
    }

    public void Clear()
    {
      BaseClear();
    }

    protected override ConfigurationElement CreateNewElement()
    {
      return new ServiceConfig();
    }

    protected override object GetElementKey(ConfigurationElement element)
    {
      return ((ServiceConfig) element).Port;
    }

    public void Remove(ServiceConfig serviceConfig)
    {
      BaseRemove(serviceConfig.Port);
    }

    public void RemoveAt(int index)
    {
      BaseRemoveAt(index);
    }

    public void Remove(string name)
    {
      BaseRemove(name);
    }
  }

The part I am missing is what to do for the handler. Originally, I tried to implement an IConfigurationSectionHandler but found two things:

1. it didn’t work
2. it’s deprecated.

I’m completely lost now on what to do so I can read my data from config. Any help please!

Answer 1

The previous answer is correct but I’ll give you all the code as well.

Your app.config should look like this:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
   <configSections>
      <section name="ServicesSection" type="RT.Core.Config.ServiceConfigurationSection, RT.Core"/>
   </configSections>
   <ServicesSection>
      <Services>
         <add Port="6996" ReportType="File" />
         <add Port="7001" ReportType="Other" />
      </Services>
   </ServicesSection>
</configuration>

Your ServiceConfig and ServiceCollection classes remain unchanged.

You need a new class:

public class ServiceConfigurationSection : ConfigurationSection
{
   [ConfigurationProperty("Services", IsDefaultCollection = false)]
   [ConfigurationCollection(typeof(ServiceCollection),
       AddItemName = "add",
       ClearItemsName = "clear",
       RemoveItemName = "remove")]
   public ServiceCollection Services
   {
      get
      {
         return (ServiceCollection)base["Services"];
      }
   }
}

And that should do the trick. To consume it you can use:

ServiceConfigurationSection serviceConfigSection =
   ConfigurationManager.GetSection("ServicesSection") as ServiceConfigurationSection;

ServiceConfig serviceConfig = serviceConfigSection.Services[0];