ConfigurationBuilder Class

Definition

public ref class ConfigurationBuilder abstract : System::Configuration::Provider::ProviderBase

public abstract class ConfigurationBuilder : System.Configuration.Provider.ProviderBase

type ConfigurationBuilder = class
 inherit ProviderBase

Public MustInherit Class ConfigurationBuilder
Inherits ProviderBase

Inheritance

Object

ProviderBase

ConfigurationBuilder

Examples

The following example shows how to implement a simple ConfigurationBuilder to read Environment variables:

using System;
using System.Configuration;
using System.Xml;

namespace Samples.AspNet.Config
{

 public class SampleConfigurationBuilder : ConfigurationBuilder
 {

 public override XmlNode ProcessRawXml(XmlNode rawXml) 
 {

 string rawXmlString = rawXml.OuterXml;

 if (String.IsNullOrEmpty(rawXmlString)) {
 return rawXml;
 }

 rawXmlString = Environment.ExpandEnvironmentVariables(rawXmlString);

 XmlDocument doc = new XmlDocument();
 doc.PreserveWhitespace = true;
 doc.LoadXml(rawXmlString);
 return doc.DocumentElement;
 }

 public override ConfigurationSection ProcessConfigurationSection(ConfigurationSection configSection) 
 => configSection;
 }
}

Imports System.Configuration
Imports System.Xml

Public Class SampleConfigurationBuilder : Inherits ConfigurationBuilder

 Public Overrides Function ProcessRawXml(rawXml As XmlNode) As XmlNode

 Dim rawXmlString As String = rawXml.OuterXml

 If String.IsNullOrEmpty(rawXmlString) Then
 Return rawXml
 End If

 rawXmlString = Environment.ExpandEnvironmentVariables(rawXmlString)

 Dim doc As New XmlDocument()
 doc.PreserveWhitespace = True
 doc.LoadXml(rawXmlString)
 Return doc.DocumentElement
 End Function

 Public Overrides Function ProcessConfigurationSection(configSection As ConfigurationSection) As ConfigurationSection
 Return configSection
 End Function

End Class

The following example is an excerpt of the configuration file as it applies to the previous example. This applies environment variables to the appSettings configuration and makes those values available under ConfigurationManager.AppSettings.

<!-- To declare and use Configuration Builders in your configuration chain, update your app.config or web.config file as follows: -->

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

<configBuilders>
 <builders>
 <add name="SampleConfigurationBuilder" type="CustomConfigBuilders.MyConfigBuilder, CustomConfigBuilders" />
 </builders>
</configBuilders>

<!-- To apply Configuration Builders to a configuration section, use the 'configBuilders' tag as follows: -->
<appSettings configBuilders="SampleConfigurationBuilder">
 <add key="COMPUTERNAME" value="Will Be Replaced by EnvironmentVariable" />
</appSettings>

Remarks

Derive from this class to read configuration from an external source that you would like to consume in your .NET Framework application using the standard ConfigurationManager API.