An exception is thrown when app setting doesn't exist.

[baralong]

It'd be nice to be able to specify a "default [true|false] if not present" option on the toggle. It's a bit more defensive incase someone stuffs up the web.config.

[jason-roberts]

This is by design, FeatureToggle will never attempt to guess whether the feature should be enabled or not. In saying this, the following enhancement is planned for v3, though its use will probably be discouraged :) #61

[baralong]

I agree that FeatureToggle should never guess what I'd like, but providing an explicit default would be very handy. Also, it'd preferable to throw a specific exception rather than system.Exception.

I've got a work around for now, it's a little verbose but I couldn't override the Feature Enabled to add a try {...} catch{...} block. I'll look forward to the next version :)

public class AlertsFeature : SimpleFeatureToggle
{
    private IBooleanToggleValueProvider _toggleValueProvider;

    public override IBooleanToggleValueProvider ToggleValueProvider
    {
        get { return _toggleValueProvider; }
        set { _toggleValueProvider = new DefaultingToggleProvider(false, value); }
    }
}

public class DefaultingToggleProvider : IBooleanToggleValueProvider
{
    private readonly bool _defaultValue;
    private readonly IBooleanToggleValueProvider _baseProvider;

    public DefaultingToggleProvider(bool defaultValue, IBooleanToggleValueProvider baseProvider)
    {
        _defaultValue = defaultValue;
        _baseProvider = baseProvider;
    }

    public bool EvaluateBooleanToggleValue(IFeatureToggle toggle)
    {
        try
        {
            return _baseProvider.EvaluateBooleanToggleValue(toggle);
        }
        catch (Exception)
        {
            return _defaultValue;
        }
    }
}

[jason-roberts]

No worries, if you have any other ideas for improvements feel free to add issues for them :)