Fix regression, avoid null key.

diff --git a/mcs/class/System.ServiceModel/System.ServiceModel.Dispatcher/SessionInstanceContextProvider.cs b/mcs/class/System.ServiceModel/System.ServiceModel.Dispatcher/SessionInstanceContextProvider.cs
index adb081485e379e56d725beaf73af2ef763e2f005..6099209e072e36f5e829406d93f117b548c1d587 100644 (file)
--- a/mcs/class/System.ServiceModel/System.ServiceModel.Dispatcher/SessionInstanceContextProvider.cs
+++ b/mcs/class/System.ServiceModel/System.ServiceModel.Dispatcher/SessionInstanceContextProvider.cs
@@ -46,13 +46,13 @@ namespace System.ServiceModel.Dispatcher
                public InstanceContext GetExistingInstanceContext (Message message, IContextChannel channel)
                {
                        InstanceContext ctx;
-                       var key = channel.SessionId;
+                       var key = channel.SessionId ?? String.Empty;
                        return pool.TryGetValue (key, out ctx) ? ctx : null;
                }
 
                public void InitializeInstanceContext (InstanceContext instanceContext, Message message, IContextChannel channel)
                {
-                       var key = channel.SessionId;
+                       var key = channel.SessionId ?? String.Empty;
                        pool [key] = instanceContext;
                }