ConfigurationManager Class
Provides access to configuration files for client applications. This class cannot be inherited.
Assembly: System.Configuration (in System.Configuration.dll)
| Name | Description | |
|---|---|---|
![]() ![]() | AppSettings | Gets the AppSettingsSection data for the current application's default configuration. |
![]() ![]() | ConnectionStrings | Gets the ConnectionStringsSection data for the current application's default configuration. |
| Name | Description | |
|---|---|---|
![]() ![]() | GetSection(String) | Retrieves a specified configuration section for the current application's default configuration. |
![]() ![]() | OpenExeConfiguration(ConfigurationUserLevel) | Opens the configuration file for the current application as a Configuration object. |
![]() ![]() | OpenExeConfiguration(String) | Opens the specified client configuration file as a Configuration object. |
![]() ![]() | OpenMachineConfiguration() | Opens the machine configuration file on the current computer as a Configuration object. |
![]() ![]() | OpenMappedExeConfiguration(ExeConfigurationFileMap, ConfigurationUserLevel) | Opens the specified client configuration file as a Configuration object that uses the specified file mapping and user level. |
![]() ![]() | OpenMappedExeConfiguration(ExeConfigurationFileMap, ConfigurationUserLevel, Boolean) | Opens the specified client configuration file as a Configuration object that uses the specified file mapping, user level, and preload option. |
![]() ![]() | OpenMappedMachineConfiguration(ConfigurationFileMap) | Opens the machine configuration file as a Configuration object that uses the specified file mapping. |
![]() ![]() | RefreshSection(String) | Refreshes the named section so the next time that it is retrieved it will be re-read from disk. |
The ConfigurationManager class enables you to access machine, application, and user configuration information. This class replaces the ConfigurationSettings class, which is deprecated. For web applications, use the WebConfigurationManager class.
To use the ConfigurationManager class, your project must reference the System.Configuration assembly. By default, some project templates, like Console Application, do not reference this assembly so you must manually reference it.
Note |
|---|
The name and location of the application configuration file depend on the application's host. For more information, see NIB: Application Configuration Files. |
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 first example shows a simple console application that reads application settings, adds a new setting, and updates an existing setting.
Imports System.Configuration Module Module1 Sub Main() ReadAllSettings() ReadSetting("Setting1") ReadSetting("NotValid") AddUpdateAppSettings("NewSetting", "May 7, 2014") AddUpdateAppSettings("Setting1", "May 8, 2014") ReadAllSettings() End Sub Sub ReadAllSettings() Try Dim appSettings = ConfigurationManager.AppSettings If appSettings.Count = 0 Then Console.WriteLine("AppSettings is empty.") Else For Each key As String In appSettings.AllKeys Console.WriteLine("Key: {0} Value: {1}", key, appSettings(key)) Next End If Catch e As ConfigurationErrorsException Console.WriteLine("Error reading app settings") End Try End Sub Sub ReadSetting(key As String) Try Dim appSettings = ConfigurationManager.AppSettings Dim result As String = appSettings(key) If IsNothing(result) Then result = "Not found" End If Console.WriteLine(result) Catch e As ConfigurationErrorsException Console.WriteLine("Error reading app settings") End Try End Sub Sub AddUpdateAppSettings(key As String, value As String) Try Dim configFile = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None) Dim settings = configFile.AppSettings.Settings If IsNothing(settings(key)) Then settings.Add(key, value) Else settings(key).Value = value End If configFile.Save(ConfigurationSaveMode.Modified) ConfigurationManager.RefreshSection(configFile.AppSettings.SectionInformation.Name) Catch e As ConfigurationErrorsException Console.WriteLine("Error writing app settings") End Try End Sub End Module
The previous example assumes your project has an App.config file as shown below.
<?xml version="1.0" encoding="utf-8" ?> <configuration> <startup> <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" /> </startup> <appSettings> <add key="Setting1" value="May 5, 2014"/> <add key="Setting2" value="May 6, 2014"/> </appSettings> </configuration>
The following example shows how to use a connection string to read data from a database.
Imports System.Configuration Imports System.Data.SqlClient Module Module1 Sub Main() ReadProducts() End Sub Sub ReadProducts() Dim connectionString = ConfigurationManager.ConnectionStrings("WingtipToys").ConnectionString Dim queryString = "SELECT Id, ProductName FROM dbo.Products;" Using connection As New SqlConnection(connectionString) Dim command = New SqlCommand(queryString, connection) connection.Open() Using reader As SqlDataReader = command.ExecuteReader() While reader.Read() Console.WriteLine(String.Format("{0}, {1}", reader(0), reader(1))) End While End Using End Using End Sub End Module
The previous example assumes your project has an App.config as shown below.
<?xml version="1.0" encoding="utf-8" ?> <configuration> <startup> <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" /> </startup> <connectionStrings> <add name="WingtipToys" connectionString="Data Source=(LocalDB)\v11.0;Initial Catalog=WingtipToys;Integrated Security=True;Pooling=False" /> </connectionStrings> </configuration>
Available since 2.0
Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.



