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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)

public class AppSettingsReader

The AppSettingsReader type exposes the following members.

Public methodAppSettingsReaderInitializes a new instance of the AppSettingsReader class.

Public methodEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodGetValueGets the value for a specified key from the AppSettings property and returns an object of the specified type containing the value from the configuration.
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)

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

using System;
using System.Collections.Specialized;
using System.Configuration;

    class UsingAppSettingsReader
        static void DisplayAppSettings()


                AppSettingsReader reader = new AppSettingsReader();

                NameValueCollection appSettings = ConfigurationManager.AppSettings;

                for (int i = 0; i < appSettings.Count; i++)
                    Console.WriteLine("Key : {0} Value: {1}",
                      appSettings.GetKey(i), appSettings[i]);

            catch (ConfigurationErrorsException e)
                Console.WriteLine("[DisplayAppSettings: {0}]", e.ToString());


        static void CreateAppSettings()
                // Get the count of the Application Settings.
                int appSettingsCount = ConfigurationManager.AppSettings.Count;

                string asName = "Key" + appSettingsCount.ToString();

                // Get the configuration file.
                System.Configuration.Configuration config =

                // Add an Application setting.
                  DateTime.Now.ToLongDateString() + " " +

                // Save the configuration file.

                // Force a reload of a changed section.
            catch (ConfigurationErrorsException e)
                Console.WriteLine("[CreateAppSettings: {0}]",

        static void Main(string[] args)

            string selection = "";

            while (selection.ToLower() != "q")
                // Create appSettings section.

                // Display appSettings section.

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

                selection = Console.ReadLine();

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

<?xml version="1.0" encoding="utf-8"?>
        <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" />

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

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