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AppSettingsReader Class

Provides a method for reading values of a particular type from the configuration.

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

'Declaration
Public Class AppSettingsReader
'Usage
Dim instance As AppSettingsReader

The following example creates a configuration file that contains the <appSettings> section, and then uses the AppSettingsReader to read the settings just generated.

Imports System
Imports System.Collections.Specialized
Imports System.Configuration


Class UsingAppSettingsReader
    Private Shared Sub DisplayAppSettings()

        Try 

            Dim reader As New System.Configuration.AppSettingsReader()


            Dim appSettings As NameValueCollection = ConfigurationManager.AppSettings

            For i As Integer = 0 To appSettings.Count - 1
                Console.WriteLine("Key : {0} Value: {1}", appSettings.GetKey(i), appSettings(i))
            Next i

        Catch e As ConfigurationErrorsException
            Console.WriteLine("[DisplayAppSettings: {0}]", e.ToString())
        End Try 

    End Sub 

    Private Shared Sub CreateAppSettings()
        Try 
            ' Get the count of the Application Settings. 
            Dim appSettingsCount As Integer = ConfigurationManager.AppSettings.Count

            Dim asName As String = "Key" & appSettingsCount.ToString()

            ' Get the configuration file. 
            Dim config As System.Configuration.Configuration = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None)

            ' Add an Application setting.
            config.AppSettings.Settings.Add(asName, Date.Now.ToLongDateString() & " " & Date.Now.ToLongTimeString())

            ' Save the configuration file.
            config.Save(ConfigurationSaveMode.Modified)

            ' Force a reload of a changed section.
            ConfigurationManager.RefreshSection("appSettings")
        Catch e As ConfigurationErrorsException
            Console.WriteLine("[CreateAppSettings: {0}]", e.ToString())
        End Try 
    End Sub 

    Shared Sub Main(ByVal args() As String)

        Dim selection As String = ""

        Do While selection.ToLower() <> "q" 
            ' Create appSettings section.
            CreateAppSettings()

            ' Display appSettings section.
            DisplayAppSettings()

            Console.WriteLine()
            Console.WriteLine("Enter 'Q' to exit or press enter to continue.")
            Console.Write("> ")

            selection = Console.ReadLine()
        Loop 
    End Sub 
End Class

The following example demonstrates a configuration file used by the previous example.

<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <appSettings>
        <add key="AppStg0" value="Thursday, December 01, 2005 12:53:56 PM" />
        <add key="AppStg1" value="Thursday, December 01, 2005 12:54:15 PM" />
        <add key="AppStg2" value="Thursday, December 01, 2005 1:37:22 PM" />
    </appSettings>
</configuration>

System.Object
  System.Configuration.AppSettingsReader

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 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0
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