Multiple values for a single config key

Question

I\'m trying to use ConfigurationManager.AppSettings.GetValues() to retrieve multiple configuration values for a single key, but I\'m always receiving an array o

Answer 1

I think, you can use Custom Config Sections http://www.4guysfromrolla.com/articles/032807-1.aspx

Answer 2

I found the solution to be very simple. If all keys are going to have the same value, simply use the unique values as the keys and omit the value.

<configSections>
    <section name="appSettings" type="System.Configuration.AppSettingsSection, System.Configuration, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" restartOnExternalChanges="false" requirePermission="false"/>
    <section name="filelist" type="System.Configuration.AppSettingsSection, System.Configuration, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" restartOnExternalChanges="false" requirePermission="false"/>
 </configSections>

<filelist>
    <add key="\\C$\Temp\File01.txt"></add>
    <add key="\\C$\Temp\File02.txt"></add>
    <add key="\\C$\Temp\File03.txt"></add>
    <add key="\\C$\Temp\File04.txt"></add>
    <add key="\\C$\Temp\File05.txt"></add>
    <add key="\\C$\Temp\File06.txt"></add>
    <add key="\\C$\Temp\File07.txt"></add>
    <add key="\\C$\Temp\File08.txt"></add>
</filelist>

Then in code simply use the following:

private static List<string> GetSection(string section)
        {
            NameValueCollection sectionValues = ConfigurationManager.GetSection(section) as NameValueCollection;

            return sectionValues.AllKeys.ToList();
        }

The result is:

Answer 3

Try

<add key="mykey" value="A,B,C"/>

And

string[] mykey = ConfigurationManager.AppSettings["mykey"].Split(',');

Answer 4

I use naming convention of the keys and it works like a charm

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>
    <section name="section1" type="System.Configuration.NameValueSectionHandler"/>
  </configSections>
  <section1>
    <add key="keyname1" value="value1"/>
    <add key="keyname21" value="value21"/>
    <add key="keyname22" value="value22"/>
  </section1>
</configuration>

var section1 = ConfigurationManager.GetSection("section1") as NameValueCollection;
for (int i = 0; i < section1.AllKeys.Length; i++)
{
    //if you define the key is unique then use == operator
    if (section1.AllKeys[i] == "keyName1")
    {
        // process keyName1
    }

    // if you define the key as a list, starting with the same name, then use string StartWith function
    if (section1.AllKeys[i].Startwith("keyName2"))
    {
        // AllKeys start with keyName2 will be processed here
    }
}

Answer 5

My take on JJS's reply: Config file:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <configSections>
    <section name="List1" type="System.Configuration.AppSettingsSection, System.Configuration, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
    <section name="List2" type="System.Configuration.AppSettingsSection, System.Configuration, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
  </configSections>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5.2" />
    </startup>
  <List1>
    <add key="p-Teapot" />
    <add key="p-drongo" />
    <add key="p-heyho" />
    <add key="p-bob" />
    <add key="p-Black Adder" />
  </List1>
  <List2>
    <add key="s-Teapot" />
    <add key="s-drongo" />
    <add key="s-heyho" />
    <add key="s-bob"/>
    <add key="s-Black Adder" />
  </List2>

</configuration>

Code to retrieve into string[]

 private void button1_Click(object sender, EventArgs e)
    {

        string[] output = CollectFromConfig("List1");
        foreach (string key in output) label1.Text += key + Environment.NewLine;
        label1.Text += Environment.NewLine;
        output = CollectFromConfig("List2");
        foreach (string key in output) label1.Text += key + Environment.NewLine;
    }
    private string[] CollectFromConfig(string key)
    {
        NameValueCollection keyCollection = (NameValueCollection)ConfigurationManager.GetSection(key);
        return keyCollection.AllKeys;
    }

IMO, that's as simple as it is going to get. Feel free to prove me wrong :)

Answer 6

Here is full solution: code in aspx.cs

namespace HelloWorld
{
    public partial class _Default : Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            UrlRetrieverSection UrlAddresses = (UrlRetrieverSection)ConfigurationManager.GetSection("urlAddresses");
        }
    }

    public class UrlRetrieverSection : ConfigurationSection
    {
        [ConfigurationProperty("", IsDefaultCollection = true,IsRequired =true)]
        public UrlCollection UrlAddresses
        {
            get
            {
                return (UrlCollection)this[""];
            }
            set
            {
                this[""] = value;
            }
        }
    }


    public class UrlCollection : ConfigurationElementCollection
    {
        protected override ConfigurationElement CreateNewElement()
        {
            return new UrlElement();
        }
        protected override object GetElementKey(ConfigurationElement element)
        {
            return ((UrlElement)element).Name;
        }
    }

    public class UrlElement : ConfigurationElement
    {
        [ConfigurationProperty("name", IsRequired = true, IsKey = true)]
        public string Name
        {
            get
            {
                return (string)this["name"];
            }
            set
            {
                this["name"] = value;
            }
        }

        [ConfigurationProperty("url", IsRequired = true)]
        public string Url
        {
            get
            {
                return (string)this["url"];
            }
            set
            {
                this["url"] = value;
            }
        }

    }
}

And in web config

<configSections>
   <section name="urlAddresses" type="HelloWorld.UrlRetrieverSection" />
</configSections>
<urlAddresses>
    <add name="Google" url="http://www.google.com" />
   <add name="Yahoo"  url="http://www.yahoo.com" />
   <add name="Hotmail" url="http://www.hotmail.com/" />
</urlAddresses>