Extension method for the generic access to application settings.

AppSettings.cs

public static T AppSetting<T>(this string key)
{
    var value = default(T);

    if (ConfigurationManager.AppSettings[key] != null)
    {
        var converter = TypeDescriptor.GetConverter(typeof (T));

        value = (T)converter.ConvertFrom(ConfigurationManager.AppSettings[key]);
    }

    return value;
}