Question

I’m using a generic List to store a set of data in the viewstate. If I try sorting the list using linq in the get accessor then when I try to add a new item to the list if doesn’t work. No error, it just doesn’t add it to the list.

When I run this line of code:

MyObjectList.Add(new MyObject());

using this property doesn’t work:

public List<MyObject> MyObjectList
{
   get
   {
      if (ViewState["MyObjectList"] == null)
         ViewState["MyObjectList"] = GetDataFromDataBase();
      return ((List<MyObject>)ViewState["MyObjectList"]).OrderBy(x => x.MyObjectID).ToList();
   }
}

but using this property does (although now I have to sort every time after getting):

public List<MyObject> MyObjectList
{
   get
   {
      if (ViewState["MyObjectList"] == null)
         ViewState["MyObjectList"] = GetDataFromDataBase();
      return (List<MyObject>)ViewState["MyObjectList"];
   }
}

How am I supposed to sort the data in the get accessor?

Answer 1

.ToList creates a copy of the list. You are adding to that rather than the original list.