ParseExtension.cs

public static class ParseExtension
{
    private static CultureInfo _cultureInfo = CultureInfo.CurrentCulture;

    public static T As<T>(this object value)
    {
        var toType = typeof(T);

        if (value == null) return default(T);

        if (value is string)
        {
            if (toType == typeof(Guid))
                return As<T>(new Guid(Convert.ToString(value, _cultureInfo)), _cultureInfo);

            if ((string)value == string.Empty && toType != typeof(string))
                return As<T>(null, _cultureInfo);
        }
        else
        {
            if (typeof(T) == typeof(string))
                return As<T>(Convert.ToString(value, _cultureInfo), _cultureInfo);
        }

        if (toType.IsGenericType && toType.GetGenericTypeDefinition() == typeof(Nullable<>))
            toType = Nullable.GetUnderlyingType(toType);

        var canConvert = toType is IConvertible || (toType.IsValueType && !toType.IsEnum);

        if (canConvert)
            return (T)Convert.ChangeType(value, toType, _cultureInfo);
        return (T)value;
    }
}