How do I store a dictionary object in my web.config file?

I'd like to store a simple key/value string dictionary in my web config file. Visual Studio makes it easy to store a string collection(see sample below) but I'm not sure how to do it with a dictionary collection.

        <ArrayOfString xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
          <string>value1</string>
          <string>value2</string>
          <string>value2</string>
        </ArrayOfString>

Solution 1:

Why reinvent the wheel? The AppSettings section is designed for exactly the purpose of storing dictionary-like data in your config file.

If you don't want to put too much data in your AppSettings section, you can group your related values into their own section as follows:

<configuration>
  <configSections>
    <section 
      name="MyDictionary" 
      type="System.Configuration.NameValueFileSectionHandler,System, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
  </configSections>

  <MyDictionary>
     <add key="name1" value="value1" />
     <add key="name2" value="value2" />
     <add key="name3" value="value3" />
     <add key="name4" value="value4" />
  </MyDictionary>
</configuration>

You can access elements in this collection using

using System.Collections.Specialized;
using System.Configuration;

public string GetName1()
{
    NameValueCollection section =
        (NameValueCollection)ConfigurationManager.GetSection("MyDictionary");
    return section["name1"];
}

Solution 2:

Juliet's answer is on point, but FYI you can also put additional configs in external .config files, by setting up your web.config as follows:

<?xml version="1.0"?>
<configuration>
  <configSections>
    <!-- blah blah the default stuff here -->

    <!-- here, add your custom section -->
    <section name="DocTabMap" type="System.Configuration.NameValueFileSectionHandler, System, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
  </configSections>

  <!-- your custom section, but referenced in another file -->
  <DocTabMap file="CustomDocTabs.config" />

  <!-- etc, remainder of default web.config is here -->
</configuration>

Then, your CustomDocTabs.config looks like this:

<?xml version="1.0"?>
<DocTabMap>
  <add key="A" value="1" />
  <add key="B" value="2" />
  <add key="C" value="3" />
  <add key="D" value="4" />
</DocTabMap>

Now you can access it in code via:

NameValueCollection DocTabMap = ConfigurationManager.GetSection("DocTabMap") as NameValueCollection;
DocTabMap["A"] // == "B"