Question

http://msdn.microsoft.com/en-us/library/system.configuration.configurationpropertyattribute.aspx

Immutable types as configuration properties

In the QueueConfiguration class below QueueID returns an int. When I run the code I get this error when accessing the getter:
The value of the property ‘queueID’ cannot be parsed. The error is: Unable to find a converter that supports conversion to/from string for the property ‘queueID’ of type ‘Int32’.

If I change QueueID to return a string it works fine. Note in the microsoft link cited above that a typeconverter is not needed to return the port property as an int. I’m suppose I’m missing something obvious……

public class QueueConfiguration : ConfigurationSection
{
    [ConfigurationProperty("queueID", DefaultValue = (int)0, IsKey = true, IsRequired = true)]        
    public int QueueID
    {
        get 
        {
            return (int)this["queueID"];
        }
        set { this["queueID"] = value; }
    }

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


public class QueueConfigurationCollection : ConfigurationElementCollection
{
    internal const string PropertyName = "QueueConfiguration";

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

    protected override string ElementName
    {
        get
        {
            return PropertyName;
        }
    }

    protected override bool IsElementName(string elementName)
    {
        return elementName.Equals(PropertyName, StringComparison.InvariantCultureIgnoreCase);
    }


    public override bool IsReadOnly()
    {
        return false;
    }


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

    protected override object GetElementKey(ConfigurationElement element)
    {
        return ((QueueConfiguration)(element)).QueueID;
    }

    public QueueConfiguration this[int idx]
    {
        get
        {
            return (QueueConfiguration)BaseGet(idx);
        }
    }
}

public class QueueConfigurationSection : ConfigurationSection
{
    [ConfigurationProperty("Queues")]
    public QueueConfigurationCollection Queues
    {
        get { return ((QueueConfigurationCollection)(this["Queues"])); }
        set { this["Queues"] = value; }
    }
}

Here is my App.config (for some reason this site refuses to display the configSection portion of app config so I’ll do my best to break it:

<configSections>
 <section name="QueueConfigurations" type="STPMonitor.Common.QueueConfigurationSection, STPMonitor"/> 
</configSections>

<QueueConfigurations>
<Queues>
  <QueueConfiguration queueID="1" queueName="One"></QueueConfiguration>
  <QueueConfiguration queueID="2" queueName="Two"></QueueConfiguration>
</Queues>
</QueueConfigurations>

Answer 1

Well, I just copy-pasted and tried your code and it works without any errors. My read code was:

var section = ConfigurationManager.GetSection("QueueConfigurations") as QueueConfigurationSection;
var queueId = section.Queues[0].QueueID;
Console.Out.WriteLine("queueId = {0}", queueId);

and it prints queueId = 1

here is gist: https://gist.github.com/b8499dcfa7456624f073