Loading and retrieving key/value pairs from XML config file

Question

I want to be able to get the value from a key/value pair contained within an XML configuration file, using C# .NET.

e.g.

<add key="ConnectionString" value="whatever"/>

I'm answering my own question here, but I'm interested in seeing the alternative options for loading and retrieving a value from a key/value pair from XML - perhaps there's an easier or more concise method?

Answer 1

ConfigurationManager Provides access to configuration files for client applications. You can fetch key/Value pair using creating custom sections and using GetSection method

<MyDictionary>
        <add key="JoinG." value="[email protected]"/>
        <add key="Brancheau S." value="[email protected]"/>
        <add key="Cetrulo P." value="[email protected]"/>
        <add key="Chiu J." value="[email protected]"/>
        <add key="D'Alessio S." value="[email protected]"/>

---

NameValueCollection section = (NameValueCollection)ConfigurationManager.GetSection("MyDictionary");

You can declare your connection string using ConfigurationManager.ConnectionStrings Property it gets the ConnectionStringsSection data for the current application's default configuration. You can access your connection string as

string conStr = Convert.ToString(ConfigurationManager.ConnectionStrings["connectionStringName"]);

---

UPDATE

To define a custom configuration file use ExeConfigurationFileMap Class ConfigurationManager.OpenMappedExeConfiguration Method opens the client specified configuration file as system.Configuration.Configuration object .

 ExeConfigurationFileMap custmConfg = new ExeConfigurationFileMap();
 custmConfg.ExeConfigFilename = @"d:\test\test.XML";
 Configuration config = ConfigurationManager.OpenMappedExeConfiguration(custmConfg, ConfigurationUserLevel.None);

---

NameValueCollection coll = (NameValueCollection)ConfigurationManager.GetSection("SectionName");

Answer 2

Get the configuration file, which in my case is contained in the root of my ASP.NET server application:

var doc = XDocument.Load(Server.MapPath("~") + "\\MyConfigFile.config");

Get the key/value pairs using LINQ (in the below LINQ query we are first looking for the descendants of 'add' elements, then we are looking for the first node which has a 'key' attribute matching 'ConnectionString', then we are getting the value of the 'value' attribute):

var connectionString = doc.Descendants("add")
    .First(node => (string)node.Attribute("key") == "ConnectionString")
    .Attribute("value").Value;

Get the value of the key specified within the square brackets:

var connectionString = parameters["ConnectionString"];

The XDocument class also contains methods for updating and saving the changes back to the physical file.