`Type.GetProperties` property order

Question

Short Version

The MSDN documentation for Type.GetProperties states that the collection it returns is not guaranteed to be in alphabetical or declara

Answer 1

I use custom attributes to add the necessary metadata myself (it's used with a REST like service which consumes and returns CRLF delimited Key=Value pairs.

First, a custom attribute:

class ParameterOrderAttribute : Attribute
{
    public int Order { get; private set; }
    public ParameterOrderAttribute(int order)
    {
        Order = order;
    }
}

Then, decorate your classes:

class Response : Message
{
    [ParameterOrder(0)]
    public int Code { get; set; }
}

class RegionsResponse : Response 
{
    [ParameterOrder(1)]
    public string Regions { get; set; }
}

class HousesResponse : Response
{
    public string Houses { get; set; }
}

A handy method for converting a PropertyInfo into a sortable int:

    private int PropertyOrder(PropertyInfo propInfo)
    {
        int output;
        var orderAttr = (ParameterOrderAttribute)propInfo.GetCustomAttributes(typeof(ParameterOrderAttribute), true).SingleOrDefault();
        output = orderAttr != null ? orderAttr.Order : Int32.MaxValue;
        return output;
    }

Even better, write is as an extension:

static class PropertyInfoExtensions
{
    private static int PropertyOrder(this PropertyInfo propInfo)
    {
        int output;
        var orderAttr = (ParameterOrderAttribute)propInfo.GetCustomAttributes(typeof(ParameterOrderAttribute), true).SingleOrDefault();
        output = orderAttr != null ? orderAttr.Order : Int32.MaxValue;
        return output;
    }
}

Finally you can now query your Type object with:

        var props = from p in type.GetProperties()
                    where p.CanWrite
                    orderby p.PropertyOrder() ascending
                    select p;