Cannot implicitly convert type 'System.Linq.IQueryable<Project.Models.TaskTimeLine>' to 'Project.Models.TaskTimeLine'

I'm trying to pass a custom shaped class to a view, but I'm having a little trouble.

This is the error I'm getting.

Cannot implicitly convert type 'System.Linq.IQueryable' to 'Project.Models.TaskTimeLine'. An explicit conversion exists (are you missing a cast?)

This is the first time I've added a list to a class, and trying to pass one inside the other as it were.

Here is the class definition

  public class TaskTimeLine
  {
    public Task task { get; set; } // to hold a single object 
    public List<DateTime> scheduledDateTime { get; set; } // to hold a collection of    date times..

  }

The controller action is along the lines of this.

 [Authorize]
    public ActionResult Details2(int id)
    {
        TaskTimeLine task = new TaskTimeLine(); //create new instance of TaskTimeLine
        task = (IQueryable<TaskTimeLine>)taskRepository.GetTaskAndTimeLine(id);

        if (task == null)
            return View("NotFound");
        else
            return View("Details", task);
    }

All quite normal up until now, so I'm guessing maybe something is going wrong here.

  public IQueryable<TaskTimeLine> GetTaskAndTimeLine(int taskId)
    {
       TaskTimeLine taskTimeLine = new TaskTimeLine(); // create new main object
       taskTimeLine.scheduledDateTime = new List<DateTime>(); instanciate list object inside          
       taskTimeLine.task = db.Tasks.SingleOrDefault(d => d.id == taskId); read the record to fill the single task object


       /// Lots of logic is performed here to add loads of date records to the list object.

       /// If I add a break point and check the list I can see that all the date items have gone fine into the collection           


       return (IQueryable<TaskTimeLine>)taskTimeLine;
    }

The only reason I have so many odd casts in places is because it seemed that these helped the program compile. It currently doesn't compile, but I did get开发者_运维问答 to, but when running the actual request it fails, with the same error message.

Can anyone help, also perhaps with add a more useful title for future people who are stuck with this kind of thing.

taskTimeLine is a TaskTimeLine; why would it also be an IQueryable<TaskTimeLine>?

  TaskTimeLine taskTimeLine = new TaskTimeLine(); // create new main object
  ....
  return (IQueryable<TaskTimeLine>)taskTimeLine;

IQueryable<T> relates to sources of data - not instances of the data itself (possible exception: Enumerable.AsQueryable()).

I suspect your method GetTaskAndTimeLine should simply return TaskTimeLine; and lose a lot of the casts...

public TaskTimeLine GetTaskAndTimeLine(int taskId)
{
   TaskTimeLine taskTimeLine = new TaskTimeLine(); // create new main object
   ...[snip]
   return taskTimeLine;
}
...
TaskTimeLine task = taskRepository.GetTaskAndTimeLine(id);

I had this error too, and I solved it by adding FirstOrDefault() to the line.

In this case, at this line:

task = (IQueryable<TaskTimeLine>)taskRepository.GetTaskAndTimeLine(id).FirstOrDefault();

(This is because IQueryable expects to several object, and you cannot get some objects into one task, only if you tell it to get only one by adding FirstOrDefault().)

In the Details2 method:

TaskTimeLine task = new TaskTimeLine(); //create new instance of TaskTimeLine
task = (IQueryable<TaskTimeLine>)taskRepository.GetTaskAndTimeLine(id);

Here you are declaring task to be a TaskTimeLine, then trying to load an IQueryable<TaskTimeLine> into that variable. These types are not compatible.

Change your repository method to return a TaskTimeLine rather than an IQueryable (that will also get rid of the casting problem inside the GetTaskAndTimeLine method that Marc identifies), and remove the cast:

TaskTimeLine task = taskRepository.GetTaskAndTimeLine(id);