Model Null reference exception in mvc view

Question

The problem is getting null reference exception when passing data from controller to view

I am Passing a model to the view from the controller like this:

 {
    ViewBag.PartId = id;
    var viewmodel= new Orderviewmodelnew();
    var order = new OrderMnagernew().GetSingleOrderField(id);
    viewmodel.ProjectId=order.ProjectId;
    return View(viewmodel);
 }

And in the View I have code like this

 @model DreamTrade.Web.BL.ViewModels.OrderViewModelnew


 Home>Project @Model.ProjectID==null??//projected is of type guid

 Customer :@(Model.CreatedBy??string.empty)

 Project :@Model.ProjectID
     @Model.ProjectDetail

  CreatedBy:@Model.CreatedBy

  Creation Date:@Model.CreationDate

 CompletedBy :@Model.ModifiedBy
 Completion Date:@Model.LastModified

 @Model.Image

   @Html.Action("OrderIndex", "Ordernew", new { PartId = Guid.Parse("C0497A40-2ADE-4B23-BA9F-1694F087C3D0") })

I have Tried like this

@if(Model.ProjectId==Null)
 {/....}

In the controller i tried like this by not passing model if it is null

 var order = new OrderMnagernew().GetSingleOrderField(id);
    if(order!=null)
   {
        viewmodel.ProjectId=order.ProjectId;
        return View(viewmodel);

   }
 return View()

The problem with this the projectid in the view is showing exception.

I Want to display empty string if it is null and show the remaining part..

Answer 1

This code is wrong:

@Model.ProjectID==null??string.empty

if ProjectID is nullable type, you should write:

@(Model.ProjectID ?? string.empty)

Added:

Replace:

return View()

with:

return View(new Orderviewmodelnew())

because null object doesn't have any properties