Store and Create new WPF App Settings on Runtime

Question

based on https://learn.microsoft.com/en-us/dotnet/api/system.configuration.configurationmanager?redirectedfrom=MSDN&view=netframework-4.8

I started to use the code to Add Settings to my WPF App on runtime. We have the following Class to add/read Custom Settings:

    using System;
using System.Configuration;

namespace my.Classes
{
    class AppSettingHandler
    {
        public 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");
            }
        }

        public 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");
            }
        }

        public 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");
            }
        }
    }
}

And I like to add a new setting with name and value to my App.config with the following:

AppSettingHandler.AddUpdateAppSettings("MyCustom_Setting_" + item.DomaineName.ToString(), "Domaine: " + item.DomaineName);

I get no error and the data but my App isnt writing into the App.config. Did I miss something like to reload the Config?

Thank y

Afaik, the app settings is readonly during runtime, you can't change them, use user settings instead — Pavel Anikhouski, Feb 13 '20 at 17:04
Hi Pavel, I thought User Settings are not stored permanently? And I need to store a bit more complex Settings. I will take a look at user settings. — , Feb 14 '20 at 09:18

score 1 · Accepted Answer · answered Feb 13 '20 at 17:22

The app.config is located in the application directory to which the user has normally no write access. The ConfigurationManager is likely blocking attempts to write to it.

The ConfigurationManager handles user configuration with config files located in the users appdata folder. So you propably have to open the user configuration with

ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.PerUserRoamingAndLocal);

Also Visual Studio has designer support for settings (Add/New Item/Settings File) and the designer generated file has a Save() method.

Store and Create new WPF App Settings on Runtime

1 Answers1