Helper methods for reading app.config values.

ConfigurationHelpers.cs

/// <summary>
/// Helper methods for reading configuration values.
/// </summary>
public static class ConfigurationHelpers
{
    /// <summary>
    /// Reads an enum value from configutation.
    /// </summary>
    /// <typeparam name="T">The enum type.</typeparam>
    /// <param name="key">The configuration key.</param>
    /// <exception cref="ArgumentException">Thrown when the type is not an enum.</exception>
    /// <exception cref="ConfigurationErrorsException">Thrown when the key is not found or the value is invalid.</exception>
    /// <returns>The enum value.</returns>
    public static T ReadEnumFromConfig<T>(string key) where T : struct, IConvertible
    {
        if (typeof(T).IsEnum == false)
        {
            throw new ArgumentException("T must be an enumerated type");
        }

        T result;
        var value = ConfigurationManager.AppSettings[key];

        if (String.IsNullOrEmpty(value) || Enum.TryParse(value, true, out result) == false)
        {
            throw new ConfigurationErrorsException(String.Format("The configuration key '{0}' was not found or its value is invalid.", key));
        }

        return result;
    }

    /// <summary>
    /// Reads a Uri value from configuration.
    /// </summary>
    /// <param name="key">The configuration key.</param>
    /// <param name="kind">The <see cref="UriKind"/>.</param>
    /// <exception cref="ConfigurationErrorsException">Thrown when the key is not found or the value is invalid.</exception>
    /// <returns>The Uri value.</returns>
    public static Uri ReadUriFromConfig(string key, UriKind kind = UriKind.Absolute)
    {
        Uri result;
        var value = ConfigurationManager.AppSettings[key];

        if (String.IsNullOrEmpty(value) || Uri.TryCreate(value, kind, out result) == false)
        {
            throw new ConfigurationErrorsException(String.Format("The configuration key '{0}' was not found or its value is invalid.", key));
        }

        return result;
    }
}