How to use a App.config file in WPF applications?

I created an App.config file in my WPF application:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <appsettings>
    <add key="xmlDataDirectory" value="c:\testdata"/>
  </appsettings>
</configuration>

Then I try to read the value out with this:

string xmlDataDirectory = ConfigurationSettings.AppSettings.Get("xmlDataDirectory");

But it says this is obsolete and that I should use ConfigurationManager which I can't find, even searching in the class view.

Does anyone know how to use config files like this in WPF?

You have to reference the System.Configuration assembly which is in GAC.

Use of ConfigurationManager is not WPF-specific: it is the privileged way to access configuration information for any type of application.

Please see Microsoft Docs - ConfigurationManager Class for further info.

In my case, I followed the steps below.

App.config

<configuration>  
   <startup> 
       <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
  </startup>

 <appSettings>
   <add key="POCPublishSubscribeQueueName" value="FormatName:Direct=OS:localhost\Private$\POCPublishSubscribe"/>
 </appSettings>

</configuration>

Added System.Configuartion to my project.

Added using System.Configuration statement in file at top.

Then used this statement:

string queuePath = ConfigurationManager.AppSettings["POCPublishSubscribeQueueName"].ToString();

In your app.config, change your appsetting to:

<applicationSettings>
    <WpfApplication1.Properties.Settings>
        <setting name="appsetting" serializeAs="String">
            <value>c:\testdata.xml</value>
        </setting>
    </WpfApplication1.Properties.Settings>
</applicationSettings>

Then, in the code-behind:

string xmlDataDirectory = WpfApplication1.Properties.Settings.Default.appsetting.ToString()

You have to add the reference to System.configuration in your solution. Also, include using System.Configuration;. Once you do that, you'll have access to all the configuration settings.

You have to reference System.Configuration via explorer (not only append using System.Configuration). Then you can write:

string xmlDataDirectory = 
    System.Configuration.ConfigurationManager.AppSettings.Get("xmlDataDirectory");

Tested with VS2010 (thanks to www.developpez.net). Hope this helps.

This also works

WpfApplication1.Properties.Settings.Default["appsetting"].ToString()

You can change configuration file schema back to DotNetConfig.xsd via properties of the app.config file. To find destination of needed schema, you can search it by name or create a WinForms application, add to project the configuration file and in it's properties, you'll find full path to file.

There is a good article about Application settings on Microsoft. According to that you need to:

• manually create App.config file (from Project Context menu -> Add -> New Item... -> Application Configuration File.)
• add required sections there (I'm using only application scope settings):

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

<configuration>
	<configSections>
		<sectionGroup name="applicationSettings"
		              type="System.Configuration.ApplicationSettingsGroup, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
			<section name="DevelopmentEnvironmentManager.WPF.Properties.Settings"
			         type="System.Configuration.ClientSettingsSection, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
		</sectionGroup>
	</configSections>
	<applicationSettings>
		<DevelopmentEnvironmentManager.WPF.Properties.Settings>
			<setting name="SqliteDbFilePath" serializeAs="String">
				<value>Database.db</value>
			</setting>
			<setting name="BackgroundColor" serializeAs="String">
				<value>White</value>
			</setting>
			<setting name="TextColor" serializeAs="String">
				<value>Black</value>
			</setting>
		</DevelopmentEnvironmentManager.WPF.Properties.Settings>
	</applicationSettings>
</configuration>

NOTE: Replace 'DevelopmentEnvironmentManager.WPF' with the name of your application.

Additionally, you can go to Properies of the project and add Settings.Designer: this will add convenient designer to your project, so you don't have to edit XML manually:

To access settings from the code - simply save and close all config editors, build app and access static Propeties (again, do not forget to change app name in the namespace):

string databasePath = DevelopmentEnvironmentManager.WPF.Properties.Settings.Default.SqliteDbFilePath;

I have a Class Library WPF Project, and I Use:

'Read Settings
Dim value as string = My.Settings.my_key
value = "new value"

'Write Settings
My.Settings.my_key = value
My.Settings.Save()