[banshee/gtk3] FilteredListSourceContents: Prevent a NRE when switching view

[Bertrand Lorentz <blorentz src gnome org>]

commit 1d28a027a389e56e874cee63676e2aec57ade0b8
Author: Bertrand Lorentz <bertrand lorentz gmail com>
Date:   Sat Jul 30 18:15:04 2011 +0200

    FilteredListSourceContents: Prevent a NRE when switching view
    
    The NRE only happens because of our current issues with scrolling, but
    we can keep the added null check anyway.

 .../FilteredListSourceContents.cs                  |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/Core/Banshee.ThickClient/Banshee.Sources.Gui/FilteredListSourceContents.cs b/src/Core/Banshee.ThickClient/Banshee.Sources.Gui/FilteredListSourceContents.cs
index 640b871..205dfb7 100644
--- a/src/Core/Banshee.ThickClient/Banshee.Sources.Gui/FilteredListSourceContents.cs
+++ b/src/Core/Banshee.ThickClient/Banshee.Sources.Gui/FilteredListSourceContents.cs
@@ -324,7 +324,7 @@ namespace Banshee.Sources.Gui
 
         protected void SetModel<T> (ListView<T> view, IListModel<T> model)
         {
-            if (view.Model != null) {
+            if (view.Model != null && view.Vadjustment != null) {
                 model_positions[view.Model] = view.Vadjustment.Value;
             }