How to write to the main exe's .config userSettings section?

Question

Is there any supported API in .NET 2.0 for writing to the userSettings section of the main exe\'s .config file?

Th

Answer 1

I think yes - manually writing to the .config file is the only way. Or you can let the administrator edit the .config-file himself.

Answer 2

After some research I came up with this solution. It is a bit low level, but still goes through the .NET configuration API without having to manually parse the .config file.

static void SaveUserSettingDefault(string clientSectionName, string settingName, object settingValue)
{
    System.Configuration.Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);

    // find section group
    ConfigurationSectionGroup group = config.SectionGroups[@"userSettings"];
    if (group == null) return;

    // find client section
    ClientSettingsSection clientSection = group.Sections[clientSectionName] as ClientSettingsSection;
    if (clientSection == null) return;

    // find setting element
    SettingElement settingElement = null;
    foreach (SettingElement s in clientSection.Settings)
    {
        if (s.Name == settingName)
        {
            settingElement = s;
            break;
        }
    }
    if (settingElement == null) return;

    // remove the current value
    clientSection.Settings.Remove(settingElement);

    // change the value
    settingElement.Value.ValueXml.InnerText = settingValue.ToString();

    // add the setting
    clientSection.Settings.Add(settingElement);

    // save changes
    config.Save(ConfigurationSaveMode.Full);
} 

Given a .config with the following content:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <configSections>
        <sectionGroup name="userSettings" type="System.Configuration.UserSettingsGroup, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" >
            <section name="MyAssembly.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" allowExeDefinition="MachineToLocalUser" requirePermission="false" />
        </sectionGroup>
    </configSections>
    <userSettings>
        <MyAssembly.Properties.Settings>
            <setting name="SqlConnectionString" serializeAs="String">
                <value>Server=(local);Database=myDatabase;Integrated Security=true;</value>
            </setting>
        </MyAssembly.Properties.Settings>
    </userSettings>
</configuration>

You would use it like this:

if (RunningAsAdmin) // save value in main exe's config file
{
    SaveUserSettingDefault(@"MyAssembly.Properties.Settings", @"SQLConnectionString", theNewConnectionString);
}
else // save setting in user's config file
{
    Settings.Default. SQLConnectionString = theNewConnectionString;
    Settings.Default.Save();
}