ConfigurationManager.AppSettings Property

public:
 static property System::Collections::Specialized::NameValueCollection ^ AppSettings { System::Collections::Specialized::NameValueCollection ^ get(); };

public static System.Collections.Specialized.NameValueCollection AppSettings { get; }

static member AppSettings : System.Collections.Specialized.NameValueCollection

Public Shared ReadOnly Property AppSettings As NameValueCollection

Property Value

The contents of the AppSettingsSection object for the current application's default configuration.

Exceptions

Examples

The first example shows a simple console application that reads application settings, adds a new setting, and updates an existing setting.

using System;
using System.Configuration;

namespace ConsoleApplication1
{
 class Program
 {
 static void Main(string[] args)
 {
 ReadAllSettings();
 ReadSetting("Setting1");
 ReadSetting("NotValid");
 AddUpdateAppSettings("NewSetting", "May 7, 2014");
 AddUpdateAppSettings("Setting1", "May 8, 2014");
 ReadAllSettings();
 }

 static void ReadAllSettings()
 {
 try
 {
 var appSettings = ConfigurationManager.AppSettings;

 if (appSettings.Count == 0)
 {
 Console.WriteLine("AppSettings is empty.");
 }
 else
 {
 foreach (var key in appSettings.AllKeys)
 {
 Console.WriteLine("Key: {0} Value: {1}", key, appSettings[key]);
 }
 }
 }
 catch (ConfigurationErrorsException)
 {
 Console.WriteLine("Error reading app settings");
 }
 }

 static void ReadSetting(string key)
 {
 try
 {
 var appSettings = ConfigurationManager.AppSettings;
 string result = appSettings[key] ?? "Not Found";
 Console.WriteLine(result);
 }
 catch (ConfigurationErrorsException)
 {
 Console.WriteLine("Error reading app settings");
 }
 }

 static void AddUpdateAppSettings(string key, string value)
 {
 try
 {
 var configFile = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
 var settings = configFile.AppSettings.Settings;
 if (settings[key] == null)
 {
 settings.Add(key, value);
 }
 else
 {
 settings[key].Value = value;
 }
 configFile.Save(ConfigurationSaveMode.Modified);
 ConfigurationManager.RefreshSection(configFile.AppSettings.SectionInformation.Name);
 }
 catch (ConfigurationErrorsException)
 {
 Console.WriteLine("Error writing app settings");
 }
 }
 }
}

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

Remarks

An AppSettingsSection object contains the contents of the configuration file's appSettings section.

See also

• AppSettingsSection
• NameValueCollection