Question

I’d need to implement the “partial validation technique” on MVC 4, as reported in this answer too:

      public class DontValidateEmailAttribute : ActionFilterAttribute 
         {  public override void OnActionExecuting(ActionExecutingContext filterContext) 
                 {
                    var modelState = filterContext.Controller.ViewData.ModelState;     
                    var incomingValues = filterContext.Controller.ValueProvider;    
                    var key = modelState.Keys.Single(x => incomingValues.Equals("Email"));
                    modelState[key].Errors.Clear();  
                  }
          }

But I get the following compile error: “'System.Collections.Generic.ICollection<string>' does not contain a definition for 'Single' and no extension method 'Single' accepting a first argument of type 'System.Collections.Generic.ICollection<string>' could be found (are you missing a using directive or an assembly reference?)…”

THX

Answer 1

You are missing a using System.Linq on the top?