Is there any way to access the value of custom config section using the key as in AppSettings?

Question

I have a customized config section in my web.config like this:

     <configSection>
            <section name="CustomConfig" type="ConfigSectionRoot" allowLocation="true" allowDefinition="Everywhere"/>
        </configSection>


    <CustomConfig>
    <ConfigRoot>
        <add key="DataBase" value="CouchDB"/>
        <add key="FrontEnd" value="Asp.Net"/>
        <add key="AppName" value="Virtual WorkPlace"/>
      </ConfigRoot>
    </CustomConfig>

<AppSettings>
<add key="DataBase" value="CouchDB"/>
</AppSettings>

My ConfigSectionRoot.cs is like this:

public class ConfigSectionRoot:ConfigurationSection
    {

        [ConfigurationProperty("key", DefaultValue = "", IsKey = true, IsRequired = true)]
        public string Key
        {
            get
            {
                return ((string)(base["key"]));
            }
            set
            {
                base["key"] = value;
            }
        }

        [ConfigurationProperty("value", DefaultValue = "", IsKey = false, IsRequired = false)]
        public string Value
        {
            get
            {
                return ((string)(base["value"]));
            }
            set
            {
                base["value"] = value;
            }
        }
    }

If i use AppSettings Instead of Custom Config I could access it like:

string results= ConfigurationManager.AppSettings["Database"];
// results wil contain "CouchDB"

Is there any way to achieve the same thing in Customized Config section ??? Pls help me out

You should derive from ConfigurationSection, not ConfigurationElement. Take a look at this [example](http://stackoverflow.com/a/10718830/205859). — Ufuk Hacıoğulları, Oct 12 '12 at 10:07
@UfukHacıoğulları I have changed and i can access it. But my question is can i access the value using the key as in AppSettings — Xavier, Oct 12 '12 at 10:13
I don't think so. ConfigurationManager.AppSetting propbably checks elements inside — Ufuk Hacıoğulları, Oct 12 '12 at 10:15
@UfukHacıoğulları Fine.. Is there anything similar to that..can we use something like CustomConfig.ConfigRoot["Database"] to get the value.. — Xavier, Oct 12 '12 at 10:20
You can implement an indexer in your ConfigSectionRoot class. — Ufuk Hacıoğulları, Oct 12 '12 at 11:18
@UfukHacıoğulları Can u explain me with a sample code for that.. — Xavier, Oct 12 '12 at 11:46
Take a look at [MSDN](http://msdn.microsoft.com/en-us/library/vstudio/6x16t2tx.aspx) — Ufuk Hacıoğulları, Oct 12 '12 at 11:52
[this question](http://stackoverflow.com/q/3935331/205859) is also helpful — Ufuk Hacıoğulları, Oct 12 '12 at 12:07

Grimace of Despair · Accepted Answer · 2014-02-16T23:37:47.137

NameValueSectionHandler

If your configuration doesn't need to be more than a key-value store, I'd go for a NameValueSectionHandler.

<section name="customConfig" type="System.Configuration.NameValueSectionHandler"/>
<!-- ... -->
<customConfig>
  <add key="DataBase" value="CouchDB" />
  <add key="FrontEnd" value="Asp.Net" />
  <add key="AppName" value="Virtual WorkPlace" />
</customConfig>

You can then read it out, just like the appSettings:

var customConfig = (System.Collections.Specialized.NameValueCollection)System.Configuration.ConfigurationManager.GetSection("customConfig");//i have changed like this and it worked fine
var database = customConfig["DataBase"];

SingleTagSectionHandler

You could also achieve the same with a SingleTagSection:

<section name="customConfig" type="System.Configuration.SingleTagSectionHandler"/>
<!-- ... -->
<customConfig database="CouchDB" frontEnd="Asp.Net" appName="Virtual Workplace" />

And then query it with:

var customConfig = (System.Collections.Hashtable) System.Configuration.ConfigurationManager.GetConfig("customConfig");
var database = customConfig["database"];

Thanks for ur help.. i didn get the expected result wen tried ur code.. I hav jus made a slight alteration then it worked.. Please review it.. — Xavier, Oct 16 '12 at 06:07
I'm sorry, it was copy-paste work from what I knew and what I could quickly find online. Didn't test it through, but you solved it just right, tnx ;) — Grimace of Despair, Oct 16 '12 at 07:43

score 0 · Answer 2 · edited Oct 16 '12 at 05:50

The .NET configuration framework provides the ConfigurationElementCollection class for representing lists of elements. In the above example, your implementation of the ConfigurationElementCollection is represented by the ConfigRoot xml element. The collection should have child elements of type "ConfigSectionRoot". The ConfigSectionRoot class should inherit from ConfigurationElement, not Configuration Section.

You must create a separate class representing the CustomConfig xml element. This class is the root of you configuration and must inherit from ConfigurationSection.

public class CustomConfigConfigurationSection : ConfigurationSection
{
    public static CustomConfigConfigurationSection Section
    {
        get
        {
            return ConfigurationManager.GetSection("customConfig") as CustomConfigConfigurationSection;
        }
    }

    public ConfigConfigurationElementCollection ConfigRoot
    {
        get
        {
            return this["configRoot"] as ConfigConfigurationElementCollection;
        }
    }
}

public class ConfigConfigurationElement : ConfigurationElement
{
    [ConfigurationProperty("key")]
    public string Key
    {
        get
        {
            return (string)this["key"];
        }
    }

    [ConfigurationProperty("value")]
    public string Value
    {
        get
        {
            return (string)this["value"];
        }
    }
}

public class ConfigConfigurationElementCollection : ConfigurationElementCollection
{
    protected override ConfigurationElement CreateNewElement()
    {
        return new ConfigConfigurationElement();
    }

    protected override object GetElementKey(ConfigurationElement element)
    {
        return ((ConfigConfigurationElement)element).Key;
    }

    // Slight hack to look up the direct value property of the ConfigConfigurationElement from the collection indexer
    public new string this[string key]
    {
        get
        {
            return (base[key] as ConfigConfigurationElement).Value;//I m getting the error in this line
        }
    }
}

Direct usage:

var section = CustomConfigConfigurationSection.Section;
var value = section.ConfigRoot["key"];

Thanks for ur help.. I hav tried as u specified.. But im getting a "System.NullReferenceException: Object reference not set to an instance of an object." — Xavier, Oct 16 '12 at 05:39

Is there any way to access the value of custom config section using the key as in AppSettings?

2 Answers2

NameValueSectionHandler

SingleTagSectionHandler