Unrecognized element exception with custom C# config

Question

I have the following bits in App.config for a .NET 3.5 Windows Service:

<configSections>
    <section name="ConfigurationServiceSection" type="SomeApp.Framework.Configuration.ConfigurationServiceSection, SomeApp.Framework"/>
</configSections>

<ConfigurationServiceSection configSource="ConfigSections\configurationServiceSection.config" />

I've got this in configurationServiceSection.config:

<ConfigurationServiceSection>
    <ConfigurationServices>
        <ConfigurationService name="LocalConfig" host="localhost" port="40001" location="LON"/>
    </ConfigurationServices>
</ConfigurationServiceSection>

And here's the code:

using System.Configuration;

namespace SomeApp.Framework.Configuration
{
    public sealed class ConfigurationServiceSection : ConfigurationSection
    {
        [ConfigurationProperty("ConfigurationServices", IsDefaultCollection = true, IsRequired = true)]
        [ConfigurationCollection(typeof(ConfigurationServices))]
        public ConfigurationServices ConfigurationServices
        {
            get
            {
                return (ConfigurationServices)base["ConfigurationServices"];
            }
        }
    }

    public sealed class ConfigurationServices : ConfigurationElementCollection
    {
        protected override ConfigurationElement CreateNewElement()
        {
            return new ConfigurationService();
        }

        protected override object GetElementKey(ConfigurationElement element)
        {
            ConfigurationService configService = (ConfigurationService) element;
            return configService.Name;
        }
    }

    public sealed class ConfigurationService : ConfigurationElement
    {
        /// <summary>
        /// name
        /// </summary>
        [ConfigurationProperty("name", IsKey = true, IsRequired = true)]
        public string Name
        {
            get { return (string)this["name"]; }
            set { this["name"] = value; }
        }

        /// <summary>
        /// host
        /// </summary>
        [ConfigurationProperty("host", IsKey = false, IsRequired = true)]
        public string Host
        {
            get { return (string)this["host"]; }
            set { this["host"] = value; }
        }

        /// <summary>
        /// port
        /// </summary>
        [ConfigurationProperty("port", IsKey = false, IsRequired = true)]
        public string Port
        {
            get { return (string)this["port"]; }
            set { this["port"] = value; }
        }

        /// <summary>
        /// location
        /// </summary>
        [ConfigurationProperty("location", IsKey = false, IsRequired = true)]
        public string Location
        {
            get { return (string)this["location"]; }
            set { this["location"] = value; }
        }
    }
}

When I try to access the config with the following:

var configurationServiceSection = (ConfigurationServiceSection)configuration.GetSection("ConfigurationServiceSection");

I get this exception:

Unrecognized element 'ConfigurationService'. (C:\Code\branches\ConfigurationService\SomeApp\Src\ConfigService\SomeApp.ConfigService.WindowsService\bin\Debug\ConfigSections\configurationServiceSection.config line 3)

Everything looks in order to me?

Any ideas please? Thanks.

See Also: [How can I solve “Unrecognized element 'elementName'](http://stackoverflow.com/questions/1985047/how-can-i-solve-unrecognized-element-elementname-line-x-line-x). — Joshua Drake, Jan 17 '13 at 20:09

score 11 · Accepted Answer · answered Sep 12 '11 at 12:38

11

Ok got to the bottom of this:

I added 'AddItemName' to the ConfigurationServiceSection class, as per below:

public sealed class ConfigurationServiceSection : ConfigurationSection
{
    [ConfigurationProperty("ConfigurationServices", IsDefaultCollection = true, IsRequired = true)]
    [ConfigurationCollection(typeof(ConfigurationServices), AddItemName = "ConfigurationService")]
    public ConfigurationServices ConfigurationServices
    {
        get
        {
            return (ConfigurationServices)base["ConfigurationServices"];
        }
    }
}

Another alternative was to override the CollectionType and ElementName properties, as per below:

public override ConfigurationElementCollectionType CollectionType
{
    get { return ConfigurationElementCollectionType.BasicMap; }
}

protected override string ElementName
{
    get { return "ConfigurationService"; }
}

answered Sep 12 '11 at 12:38

Mike

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Form me it was the "return ConfigurationElementCollectionType.BasicMap;" which I needed to change to "return ConfigurationElementCollectionType.AddRemoveClearMap;" but this post helped me get to that answer! – Dib May 23 '14 at 06:29
This AddItemName solution is pretty obvious. Pretty intuitive. Pretty discoverable. Design the configuration framework so that the xml structure resembles your object model, until you try to add items to a collection, at which point you use the xml element instead of the object type/name. That'll keep 'em guessing. For about 6 hours. – Sep 17 '14 at 18:18
Overriding ElementName in the collection class was the crucial part to get this working for me. Setting AddItemName wasn't enough. Needless to say, this is missing from the MSDN examples. – Lee D Mar 08 '18 at 10:35

Unrecognized element exception with custom C# config

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