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ConfigurationManager Class

Provides access to configuration files for client applications. This class cannot be inherited.

Namespace: System.Configuration
Assembly: System.Configuration (in system.configuration.dll)

'Declaration
Public NotInheritable Class ConfigurationManager
'Usage

public final class ConfigurationManager
public final class ConfigurationManager
Not applicable.

The ConfigurationManager class enables you to access machine, application, and user configuration information. This class replaces the ConfigurationSettings class, which is deprecated.

You can use the built-in System.Configuration types or derive from them to handle configuration information. By using these types, you can work directly with configuration information and you can extend configuration files to include custom information.

The ConfigurationManager class includes members that enable you to perform the following tasks:

  • Read a section from a configuration file. To access configuration information, call the GetSection method. For some sections such as appSettings and connectionStrings, use the AppSettings and ConnectionStrings classes. These members perform read-only operations, use a single cached instance of the configuration, and are multithread aware.

  • Read and write configuration files as a whole. Your application can read and write configuration settings at any level, for itself or for other applications or computers, locally or remotely. Use one of the methods provided by the ConfigurationManager class to open a configuration file such as SampleApp.exe.config. These methods return a Configuration object that in turn exposes methods and properties you can use to work with the associated configuration files. The methods perform read or write operations and create the configuration data every time that a file is written.

  • Support configuration tasks. The following types are used to support various configuration tasks:

    In addition to working with existing configuration information, you can create and work with custom configuration elements by extending the built-in configuration types such as the ConfigurationElement, ConfigurationElementCollection, ConfigurationProperty, and ConfigurationSection classes. For an example of how to extend a built-in configuration type programmatically, see ConfigurationSection. For an example of how to extend a built-in configuration type that uses the attribute-based model, see ConfigurationElement.

Notes to Implementers: The Configuration class enables programmatic access for editing configuration files. You use one of the Open methods provided by ConfigurationManager. These methods return a Configuration object, which in turn provides the required methods and properties to handle the underlying configuration files. You can access these files for reading or writing. To read the configuration files, use GetSection or GetSectionGroup to read configuration information. The user or process that reads must have the following permissions:

  • Read permission on the configuration file at the current configuration hierarchy level.

  • Read permissions on all the parent configuration files.

If your application needs read-only access to its own configuration, we recommend that you use the GetSection method. This method provides access to the cached configuration values for the current application, which has better performance than the Configuration class. To write to the configuration files, use one of the Save methods. The user or process that writes must have the following permissions:
  • Write permission on the configuration file and directory at the current configuration hierarchy level.

  • Read permissions on all the configuration files.

The following code example shows how to use the ConfigurationManager class to access the appSettings configuration section. If the section does not exist, it is created and added to the configuration file.

Imports System
Imports System.Collections.Specialized
Imports System.Collections.ObjectModel
Imports System.Collections
Imports System.Text
Imports System.Configuration

Class UsingConfigurationManager
    
    
    ' Show how to use AppSettings.
    Shared Sub DisplayAppSettings() 
        
        ' Get the AppSettings collection.
        Dim appSettings As NameValueCollection = _
        ConfigurationManager.AppSettings
        
        Dim keys As String() = appSettings.AllKeys
        
        Console.WriteLine()
        Console.WriteLine("Application appSettings:")
        
        ' Loop to get key/value pairs.
        Dim i As Integer
        For i = 0 To appSettings.Count
            
            Console.WriteLine("#{0} Name: {1} Value: {2}", i, _
            keys(i), appSettings(i))
        Next i
    
    End Sub 'DisplayAppSettings
     
    ' Show how to use ConnectionStrings.
    Shared Sub DisplayConnectionStrings() 
        
        ' Get the ConnectionStrings collection.
        Dim connections As ConnectionStringSettingsCollection = _
        ConfigurationManager.ConnectionStrings
        
        Console.WriteLine()
        Console.WriteLine("Connection strings:")
        
        
        ' Loop to get the collection elements.
        Dim conEnum As IEnumerator = connections.GetEnumerator()
        
        Dim i As Integer = 0
        While conEnum.MoveNext()
            Dim name As String = connections(i).Name
            Dim connectionString As String = _
            connections(name).ConnectionString
            Dim provider As String = _
            connections(name).ProviderName
            
            Console.WriteLine("Name:               {0}", name)
            Console.WriteLine("Connection string:  {0}", connectionString)
            Console.WriteLine("Provider:           {0}", provider)
        End While
    
    End Sub 'DisplayConnectionStrings
     
    ' Show how to use OpenMachineConfiguration.
    Shared Sub DisplayMachineConfigSections() 
        ' Get the machine.config file.
        Dim machineConfig As Configuration = _
        ConfigurationManager.OpenMachineConfiguration()
        
        Dim sections As ConfigurationSectionCollection = _
        machineConfig.Sections
        
        Console.WriteLine()
        Console.WriteLine("Sections in machine.config:")
        
        ' Loop to get the sections machine.config.
        Dim section As ConfigurationSection
        For Each section In  sections
            Dim name As String = section.SectionInformation.Name
            Console.WriteLine("Name: {0}", name)
        Next section
    
    End Sub 'DisplayMachineConfigSections
     
    
    ' Show how to use OpenExeConfiguration(ConfigurationUserLevel) 
    ' and RefreshSection. 
    Shared Sub UpdateAppSettings() 
        ' Get the configuration file.
        Dim config As System.Configuration.Configuration = _
        ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None)
        
        ' Add an entry to appSettings.
        Dim appStgCnt As Integer = _
        ConfigurationManager.AppSettings.Count
        Dim newKey As String = "NewKey" + appStgCnt.ToString()
        
        Dim newValue As String = DateTime.Now.ToLongDateString() + " " + _
        DateTime.Now.ToLongTimeString()
        
        config.AppSettings.Settings.Add(newKey, newValue)
        
        ' Save the configuration file.
        config.Save(ConfigurationSaveMode.Modified)
        
        ' Force a reload of the changed section.
        ConfigurationManager.RefreshSection("appSettings")
    
    End Sub 'UpdateAppSettings
     
    ' Show how to use OpenExeConfiguration(string).
    Shared Sub DisplayAppSettingsRawXml() 
        
        
        ' Get the application path.
        Dim exePath As String = System.IO.Path.Combine( _
        Environment.CurrentDirectory, "ConfigurationManager.exe")
        
        ' Get the configuration file.
        Dim config As System.Configuration.Configuration = _
        ConfigurationManager.OpenExeConfiguration(exePath)
        
        ' Get the AppSetins section.
        Dim appSettingSection As AppSettingsSection = _
        config.AppSettings
        
        ' Display raw xml.
        Console.WriteLine( _
        appSettingSection.SectionInformation.GetRawXml())
    
    End Sub 'DisplayAppSettingsRawXml
     
    
    ' Show how to use GetSection.
    Shared Sub DisplayAppSettingsSectionRawXml() 
        
        ' Get the configuration file.
        Dim config As System.Configuration.Configuration = _
        ConfigurationManager.OpenExeConfiguration( _
        ConfigurationUserLevel.None)
        
        ' Get the AppSetins section.
        Dim appSettingSection As AppSettingsSection = _
        CType(config.GetSection("appSettings"), AppSettingsSection)
        
        ' Display raw xml.
        Console.WriteLine(appSettingSection.SectionInformation.GetRawXml())
    
    End Sub 'DisplayAppSettingsSectionRawXml
     
    
    ' Show how to use OpenMappedMachineConfiguration.
    Shared Sub DisplayMappedMachineConfigurationFileSections() 
        ' Get the machine.config file.
        Dim machineConfig As Configuration = _
        ConfigurationManager.OpenMachineConfiguration()
        
        ' Map to the machine configuration file.
        Dim configFile As New ConfigurationFileMap(machineConfig.FilePath)
        Dim config As Configuration = _
        ConfigurationManager.OpenMappedMachineConfiguration(configFile)
        
        ' Display the configuration file sections.
        Dim sections As ConfigurationSectionCollection = config.Sections
        
        Console.WriteLine()
        Console.WriteLine("Sections in machine.config:")
        
        ' Loop to get the sections machine.config.
        Dim section As ConfigurationSection
        For Each section In  sections
            Dim name As String = section.SectionInformation.Name
            Console.WriteLine("Name: {0}", name)
        Next section
    
    End Sub 'DisplayMappedMachineConfigurationFileSections
     
    
    ' Show how to use OpenMappedExeConfiguration.
    Shared Sub DisplayMappedExeConfigurationFileSections() 
        ' Get the application configuration file path.
        Dim exeFilePath As String = System.IO.Path.Combine( _
        Environment.CurrentDirectory, "ConfigurationManager.exe.config")
        
        ' Map to the application configuration file.
        Dim configFile As New ExeConfigurationFileMap()
        configFile.ExeConfigFilename = exeFilePath
        Dim config As Configuration = _
        ConfigurationManager.OpenMappedExeConfiguration(configFile, _
        ConfigurationUserLevel.None)
        
        ' Display the configuration file sections.
        Dim sections As ConfigurationSectionCollection = config.Sections
        
        Console.WriteLine()
        Console.WriteLine("Sections in machine.config:")
        
        ' Loop to get the sections machine.config.
        Dim section As ConfigurationSection
        For Each section In  sections
            Dim name As String = section.SectionInformation.Name
            Console.WriteLine("Name: {0}", name)
        Next section
    
    End Sub 'DisplayMappedExeConfigurationFileSections
     
    Shared Sub Main(ByVal args() As String) 
        
        ' Show how to use OpenExeConfiguration() and RefreshSection.
        UpdateAppSettings()
        
        ' Show how to use AppSettings.
        DisplayAppSettings()
        
        ' Show how to use ConnectionStrings.
        DisplayConnectionStrings()
        
        ' Show how to use OpenExeConfiguration(string).
        DisplayAppSettingsRawXml()
        
        ' Show how to use GetSection.
        DisplayAppSettingsSectionRawXml()
        
        ' Show how to use OpenMappedMachineConfiguration.
        DisplayMappedMachineConfigurationFileSections()
        
        ' Show how to use OpenMappedExeConfiguration.
        DisplayMappedExeConfigurationFileSections()
        
        ' Show how to use OpenMachineConfiguration.
        DisplayMachineConfigSections()
    
    End Sub 'Main 
End Class 'UsingConfigurationManager


The example works with the elements illustrated in the following configuration file, which is generated the first time that you run the example.

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <appSettings>
    <add key="NewKey0" value="Monday, January 23, 2006 2:56:14 PM" />
    <add key="NewKey1" value="Monday, January 23, 2006 3:15:18 PM" />
    <add key="NewKey2" value="Monday, January 23, 2006 3:16:29 PM" />
  </appSettings>
</configuration>

System.Object
  System.Configuration.ConfigurationManager

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0

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