MVC到MVC2错误

Question

I've just updated to VS2010 (rc) and subsequently been forced to update my projects and convert to MVC2 (ta microsoft)... which has scuppered the first app its touched.

Error   2   'System.Web.Mvc.IValueProvider' does not contain a definition for
'Where' and no extension method 'Where' accepting a first argument of type 
'System.Web.Mvc.IValueProvider' could be found (are you missing a using directive or an 
assembly reference?)    ~\Controllers\DiscountsController.cs    51  39  ODSe

Considering I know this works in VS2008 - MVC1 I'm a tad thrown. Anyone?

I currently have (included)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Web.Mvc.Ajax;
using ODSe.Models;
using System.Text;
using System.Text.RegularExpressions;
using System.Net.Mail;

Shouldnt need to be .net 4 as the original project was 3.5; and MVC2 is .net 3.5 (ASP.NET MVC 2 RC 2 provides a new Model-View-Controller (MVC) framework on top of the existing ASP.NET 3.5 SP1 runtime.)

Code Around 51

foreach (var x in this.ValueProvider.Where(k => k.Key.StartsWith("discount.")))
{
   if (String.IsNullOrEmpty(x.Value.AttemptedValue))
   {
     ModelState.SetModelValue(x.Key, new ValueProviderResult(ValueProvider[x.Key].AttemptedValue, collection[x.Key], System.Globalization.CultureInfo.CurrentCulture));
                        Discount = true;
   }
}

When the code was written for MVC(1) in VS2008 this.ValueProvider was "IDictionary ControllerBase.ValueProvider. In MVC(2) VS2010 it throws a hissy fit about using where though this is apparently fine.

foreach (var x in this.ValueProvider)
                    {
                        if (x.Key.StartsWith("discount."))
                        {
                            if (String.IsNullOrEmpty(x.Value.AttemptedValue))
                            {
                                ModelState.SetModelValue(x.Key, new ValueProviderResult(ValueProvider[x.Key].AttemptedValue, collection[x.Key], System.Globalization.CultureInfo.CurrentCulture));
                                Discount = true;
                            }
                        }
                    }

If not a butt ugly piece of code; Legacy Code is soooo much fun

Answer 1

IValueProvider does not extend IEnumerable<T> , so LINQ extension methods like Where won't be available.

IValueProvider is new in MVC 2, so it's possible that you are accessing a property that was IEnumerable<T> in MVC 1.

Can you provide the code at NewDiscountsController.cs 51 ?