How to access configuration provider values in asp.net core startup

Question

In my asp.net core 3.1 project I have setup a custom sql provider which is working great. In my Startup I want to load only the values from the SQLConfigurationProvider into a separate dictionary for use throughout my app. I can see that the configuration object contains a collection of providers as per below screenshot. However I cannot find a way to access only the SQLConfigurationProvider and get the subsequent values. Is this possible?

Answer 1

According to your description, I suggest you could firstly use Configuration.Providers to get the SQLConfigurationProvider.

But the ConfigurationProvider's data property is protected, so we should write a extension method to get the value and set it into a directory.

More details, you could refer to below codes:

Create a extension class:

public static class ConfigurationProviderExtensions
{
    public static HashSet<string> GetFullKeyNames(this IConfigurationProvider provider, string rootKey, HashSet<string> initialKeys)
    {
        foreach (var key in provider.GetChildKeys(Enumerable.Empty<string>(), rootKey))
        {
            string surrogateKey = key;
            if (rootKey != null)
            {
                surrogateKey = rootKey + ":" + key;
            }

            GetFullKeyNames(provider, surrogateKey, initialKeys);

            if (!initialKeys.Any(k => k.StartsWith(surrogateKey)))
            {
                initialKeys.Add(surrogateKey);
            }
        }

        return initialKeys;
    }
}

Then you could add below codes to get the provider and get the value..

// Replace the EnvironmentVariablesConfigurationProvider to your provider 
var re =  ((ConfigurationRoot)Configuration).Providers.FirstOrDefault(x=>x.GetType() == typeof(EnvironmentVariablesConfigurationProvider));

var directory = new Dictionary<string, string>();

foreach (var key in re.GetFullKeyNames(null, new HashSet<string>()).OrderBy(p => p))
{
    if (re.TryGet(key, out var value))
    {
        directory.Add(key, value);
    }
}

Result: