How to change in runtime application settings

Question

I'm trying to change in runtime one key of my applications settings file, but it does not work.

I do on that way:

ConfigurationSettings.AppSettings["XPTO"] = "HELLO";

It seems that it only changes in memory, not on the file.

Does anyone knows how to do this?

Thanks.

Palacios

Answer 1

Take a look at my overview of .NET settings files...In short, I think you want a user-scoped setting. It will behave more like you expect.

Edit: If you are using the settings designer in Visual Studio, then simply change the "Scope" to "User". If not, you should be able to do the equivalent programmatically.

Dur

Please note that when changing the Settings and saving, the settings won't be changed in the bin folder, but in [userfolder]\Local Settings\Application Data\[company name]\[application].exe[hash string]\[version]\user.config – Gall

In more recent versions of Windows it will be changed on [userfolder]\AppData\Local\[company name]\[application].exe[hash string]\[version]\user.config – Gall

@Jader Yep. I do mention this briefly in my overview and give programmatic ways to retrieve the resulting path. But thanks for sharing these details. – Dur

Answer 2

Assuming your app has write permissions on the file...

    Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);  // the config that applies to all users
    AppSettingsSection appSettings = config.AppSettings;

    if (appSettings.IsReadOnly() == false)
    {
        appSettings("Key").Value = "new value";

        config.Save();
    }

I'm ignoring all the possible exceptions that can be thrown...

Lagerkvist

How can I hava access to ConfigurationManager class. I try to use this piece of code and it results in some errors that does not konws that class :S. – Palacios

Add System.Configuration as a reference. – Lagerkvist

Answer 3

The AppSettings file is not designed to be writable. It is designed to store configurations that will not change at run time but might change over time ie: DB Connection Strings, web service URL's, etc.

So, while it may be possible to update the file in reality you should re-asses if this value should be stored there.

Detection