MVC-Create a ViewModel class instance from the urlreferrer url - asp.net-mvc

Question

Given:
request.UrlReferrer.LocalPath = "/MyApp/MyHome/List";
and I have a Route Mapping that handles this where MyHome is my controller and List is an action that takes a ViewModel. Other variations of this Route include paging and sorting but these are captured by the ViewModel.
My question is this:
How can I use the above URL to generate an instance of the related ViewModel?
EDIT: I have an JQuery Dialog that is adding/updating/deleting an item in a list that is shown by the url in the urlreferrer- the example given is the most basic. When the dialog sends the data to be a/u/d, I want to return the updated body of the list and display that. This information is handled by a different ViewModel than what is instantiated on the POST from the dialog (the url posted to is "/MyApp/MyHome/Edit/True" - for creating a new whatever). This piece follows the standard MVC process and of course works. What I want to do is create a second ViewModel based on the ViewModel for the list action and return this as a partial view containing the updated paged list.

Answer 1

Ok... I think I have this figured out. This is not pretty but it works. I welcome anybody's input to actually feed this through a ModelBinder or any other MVC artifact but here's what I came up with:
First we need to fake a request using the UrlReferrer instead of the actual url being requested:
public class FakeHttpContext : HttpContextBase
{
public FakeHttpContext(HttpContextBase currentContext)
{
_request = new FakeHttpRequest(currentContext.Request);
}
HttpRequestBase _request;
public override HttpRequestBase Request
{
get
{
return _request;
}
}
HttpResponseBase _response = new FakeHttpResponse();
public override HttpResponseBase Response
{
get
{
return _response;
}
}
class FakeHttpRequest : HttpRequestBase
{
HttpRequestBase _request;
public FakeHttpRequest(HttpRequestBase currentRequest)
{
if(currentRequest == null)
throw new ArgumentNullException();
this._request = currentRequest;
}
public override string ApplicationPath
{
get
{
return this._request.ApplicationPath;
}
}
public override string AppRelativeCurrentExecutionFilePath
{
get
{
return "~" + this._request.UrlReferrer.AbsolutePath.Remove(0, this._request.ApplicationPath.Length);
}
}
public override string PathInfo
{
get
{
return this._request.PathInfo;
}
}
}
class FakeHttpResponse : HttpResponseBase
{
}
}
Next, we feed the fake call through the RouteTable to get it broken down. and match up properties to the RouteData.Values.
public static class RouteAndModelBinder
{
public static void BuildViewModel<TViewModel>(ControllerContext context, TViewModel model)
{
FakeHttpContext fake = new FakeHttpContext(context.HttpContext);
RouteData test = RouteTable.Routes.GetRouteData(fake);
PropertyInfo[] properties = typeof(TViewModel).GetProperties();
string value;
foreach(PropertyInfo info in properties)
{
if(test.Values.ContainsKey(info.Name))
{
value = (string)test.Values[info.Name];
if(value == null)
{
continue;
}
if(info.PropertyType.IsGenericType &&
info.PropertyType.GetGenericTypeDefinition() == typeof(Nullable<>))
{
Type[] nullables = info.PropertyType.GetGenericArguments();
if(nullables.Length > 0)
{
Type nullableType = nullables[0];
if(nullableType.BaseType == typeof(Enum))
{
object o = Enum.Parse(nullableType, value);
info.SetValue(model, o, null);
}
else if(nullableType == typeof(Int32))
{
info.SetValue(model, int.Parse(value), null);
}
else
{
info.SetValue(model, Convert.ChangeType(value, info.PropertyType), null);
}
}
}
else
{
if(info.PropertyType.BaseType == typeof(Enum))
{
object o = Enum.Parse(info.PropertyType.BaseType, value);
info.SetValue(model, o, null);
}
else if(info.PropertyType == typeof(Int32))
{
info.SetValue(model, int.Parse(value), null);
}
else
{
info.SetValue(model, value, null);
}
}
}
}
}
}
Again, I welcome anybody's suggestions on how I can do this with already established MVC code (ie, ModelBinders, etc). I took some ideas and probably code from here (for the nullable type) and here.