Adding array of complex types to RouteValueDictionary

Question

I was wondering if there is an elegant way to add an array of complex types to a RouteValueDictionary or compatible type?

For example, if I have a class and an action:

public class TestObject
{
    public string Name { get; set; }
    public int Count { get; set; }

    public TestObject()
    {
    }

    public TestObject(string name, int count)
    {
        this.Name = name;
        this.Count = count;
    }
}

public ActionResult Test(ICollection<TestObjects> t)
{
    return View();
}

then I know that if I call this action via the URL "/Test?t[0].Name=One&t[0].Count=1&t[1].Name=Two&t[1].Count=2" that MVC will map those query string parameters back into the ICollection type automatically. However, if I am manually creating a link somewhere using Url.Action(), and I want to pass a RouteValueDictionary of the parameters, when I add an ICollection to the RouteValueDictionary, Url.Action just renders it as the type, like &t=System.Collections.Generic.List.

For example:

RouteValueDictionary routeValDict = new RouteValueDictionary();
List<TestObject> testObjects = new List<TestObject>();

testObjects.Add(new TestObject("One", 1));
testObjects.Add(new TestObject("Two", 2));
routeValDict.Add("t", testObjects);

// Does not properly create the parameters for the List<TestObject> collection.
string url = Url.Action("Test", "Test", routeValDict);    

Is there any way to get it to automatically render that collection into the format that MVC also understands how to map, or must I do this manually?

What am I missing, why would they make it so this beautiful mapping exists into an Action but not provide a way to manually work in the reverse direction for creating URLs?

Answer 1

I ran into this problem as well and used Zack's code but found a bug in it. If the IEnumerable is an array of string (string[]) then there is a problem. So i thaught I'd share my extended version.

    public static RouteValueDictionary ToRouteValueDictionaryWithCollection(this RouteValueDictionary routeValues)
    {
        var newRouteValues = new RouteValueDictionary();

        foreach(var key in routeValues.Keys)
        {
            object value = routeValues[key];

            if(value is IEnumerable && !(value is string))
            {
                int index = 0;
                foreach(object val in (IEnumerable)value)
                {
                    if(val is string || val.GetType().IsPrimitive)
                    {
                        newRouteValues.Add(String.Format("{0}[{1}]", key, index), val);
                    }
                    else
                    {
                        var properties = val.GetType().GetProperties();
                        foreach(var propInfo in properties)
                        {
                            newRouteValues.Add(
                                String.Format("{0}[{1}].{2}", key, index, propInfo.Name),
                                propInfo.GetValue(val));
                        }
                    }
                    index++;
                }
            }
            else
            {
                newRouteValues.Add(key, value);
            }
        }

        return newRouteValues;
    }

Answer 2

Well, I am open to other (more elegant) solutions, but I did get it working by taking the extension method found at this q/a: https://stackoverflow.com/a/5208050/1228414 and adapting it to use reflection for complex type properties instead of assuming primitive type arrays.

My code:

public static RouteValueDictionary ToRouteValueDictionaryWithCollection(this RouteValueDictionary routeValues)
{
    RouteValueDictionary newRouteValues = new RouteValueDictionary();

    foreach (var key in routeValues.Keys)
    {
        object value = routeValues[key];

        if (value is IEnumerable && !(value is string))
        {
            int index = 0;
            foreach (object val in (IEnumerable)value)
            {
                PropertyInfo[] properties = val.GetType().GetProperties();
                foreach (PropertyInfo propInfo in properties)
                {
                    newRouteValues.Add(
                        String.Format("{0}[{1}].{2}", key, index, propInfo.Name),
                        propInfo.GetValue(val));
                }
                index++;
            }
        }
        else
        {
            newRouteValues.Add(key, value);
        }
    }

    return newRouteValues;
}