/// <summary>
/// Creates an instance of the <see cref="IConnectionProvider"/> class.
/// <paramref name="key"/>.
/// </summary>
/// <param name="key">
/// The name of the provider that should be created
/// </param>
/// <returns>
/// The newly created <see cref="IConnectionProvider"/> object.
/// </returns>
/// <exception cref="KeyNotFoundException"></exception>
/// <remarks>
/// This method used the <paramref name="key"/> as a index into the list
/// of providers that was specified in constructor and them uses the found
/// <see cref=" IProviderNode"/> to construct an instance of the
/// <see cref="IConnectionProvider"/> class, if a provider with name
/// <paramref name="key"/> is not found, this method raises a
/// <see cref="KeyNotFoundException"/> exception.
/// </remarks>
public override IConnectionProvider Load(string key)
{
IProviderNode provider = providers_[key];
return(ProviderFactory <IConnectionProviderFactory>
.CreateProviderFactory(provider)
.CreateProvider(provider.Options.ToDictionary()));
}