app.config (SIMPLE)

Posted on 2007-03-30
Medium Priority
Last Modified: 2012-06-22
I am planning on using the app.config file to read in some user defined data.  I have a number of form names that will continually change over time.

Can I have the same key listed twice?

<add key=FormName value=RothIRA>
<addkey=FormName value=TOA>


I was hoping to loop through (in code) and check for all of the FormNames.  Anything found in the appConfig.....I'll be applying logic to in my app.

Is it possible to list multiple entries with the same key name?   Is there a better way to go about this?


Question by:JohnnyKnoxville
  • 5
LVL 22

Expert Comment

ID: 18826425

No, each key must be unique.

On the other hand, if you use XML, and serialize the data into a class, you can easily create an array of values.
LVL 22

Expert Comment

ID: 18826472
Here's a sample from code that I use all the time:


</xml version="1.0" encoding="utf-8" ?>

    <section name="Section1"
             type="ConfigSectionHandler.ConfigSectionHandler, ConfigSectionHandler" />
    <section name="Section2"
             type="ConfigSectionHandler.ConfigSectionHandler, ConfigSectionHandler" />

  <Section1 type="Namespace.Class, Namespace">
LVL 22

Expert Comment

ID: 18826481
[Add this class to your application]

using System;
using System.Xml;
using System.Xml.XPath;
using System.Xml.Serialization;
using System.Configuration;

namespace ConfigSectionHandler
    /// <summary>
    /// This class contains only one method, Create().
    /// This is designed to handle custom sections in an Applications Configuration file.
    /// By Implementing <see cref="IConfigurationSectionHandler"/>, we can implement the
    /// Create method, which will provide the XmlNode from the configuration file. This is
    /// Deserialized into an object and passed back to the Caller.
    /// </summary>
    /// <example>
    /// Here is a configuration file entry in the <c>configSections</c> sectikon of the <c>App.Config</c>
    /// file.
    ///<code>      ///
    ///&lt;section name="ServerConfig" type="ConfigSectionHandler.ConfigSectionHandler, ConfigSectionHandler" /&gt;
    ///This tells the CLR that there is a section further in, with a node name of <c>ServerConfig</c>. When this section
    ///is to be parsed, an object of type <c>ConfigSectionHandler.ConfigSectionHandler</c> which resides in the
    ///assembly <c>ConfigSectionHandler</c> will be instantiated. The CLR automatically calls a method in that object
    ///called <c>Create</c>
    public class ConfigSectionHandler : IConfigurationSectionHandler
        public ConfigSectionHandler()
            : base()

        #region IConfigurationSectionHandler Members

        /// <summary>
        /// A method which is called by the CLR when parsing the App.Config file. If custom sections
        /// are found, then an entry in the configuration file will tell the runtime to call this method,
        /// passing in the XmlNode required.
        /// </summary>
        /// <param name="parent">The configuration settings in a corresponding parent configuration section. Passed in via the CLR</param>
        /// <param name="configContext">An <see cref="HttpConfigurationContext"/> when Create is called from the ASP.NET configuration system. Otherwise,
        /// this parameter is reserved and is a null reference (Nothing in Visual Basic). Passed in via the CLR</param>
        /// <param name="section">The <see cref="XmlNode"/> that contains the configuration information from the configuration file.
        /// Provides direct access to the XML contents of the configuration section.       Passed in via the CLR.</param>
        /// <returns>The Deserialized object as an object</returns>
        /// <exception cref="System.Configuration.ConfigurationException">The Configuration file is not well formed,
        /// or the Custom section is not configured correctly, or the type of configuration handler was not specified correctly
        /// or the type of object was not specified correctly.
        /// or the copn</exception>
        public object Create(object parent, object configContext, System.Xml.XmlNode section)
                XPathNavigator xNav = section.CreateNavigator();
                string typeOfObject = (string)xNav.Evaluate("string(@type)");
                Type t = Type.GetType(typeOfObject);
                XmlSerializer ser = new XmlSerializer(t);
                XmlNodeReader xNodeReader = new XmlNodeReader(section);
                return ser.Deserialize(xNodeReader);
            catch (Exception e)
                if (e.InnerException.Message.Length > 0)
                return null;
LVL 22

Expert Comment

ID: 18826504
[Create a class that you serialize your app.config data to]

using System;
using System.Collections.Generic;
using System.Text;
using System.Xml;
using System.Xml.Serialization;

namespace Application1
    public class FirstSection
        public string[] _formName;    }
LVL 22

Accepted Solution

_TAD_ earned 200 total points
ID: 18826530
[Putting it all together]


// use configuration manager class to pull proper app.config section
// and serialize it to a class
Section1 s1 = (Section1)ConfigurationManager.GetSection("Section1");

// itterate through class data collection
for(int i=0; i<s1._formName.Length; i++)

Featured Post

Get expert help—faster!

Need expert help—fast? Use the Help Bell for personalized assistance getting answers to your important questions.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

This article is for Object-Oriented Programming (OOP) beginners. An Interface contains declarations of events, indexers, methods and/or properties. Any class which implements the Interface should provide the concrete implementation for each Inter…
Entity Framework is a powerful tool to help you interact with the DataBase but still doesn't help much when we have a Stored Procedure that returns more than one resultset. The solution takes some of out-of-the-box thinking; read on!
Free Data Recovery software is an advanced solution from Kernel Tools to recover data and files such as documents, emails, database, media and pictures, etc. It supports recovery from physical & logical drive after a hard disk crash, accidental/inte…
Watch the video of Kernel Migrator for SharePoint, which demonstrate the process easily of migration from SharePoint to SharePoint, OneDrive for Business & Google Drive servers, Public Folder to SharePoint, File Server to SharePoint. The tool has va…

621 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question