Some refactor ideas

NTwain/TentativeStateCommitable.cs

@@ -0,0 +1,47 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace NTwain
+{
+    class TentativeStateCommitable : ICommitable
+    {
+        bool _commit;
+        ITwainStateInternal _session;
+        int _origState;
+        int _newState;
+        public TentativeStateCommitable(ITwainStateInternal session, int newState)
+        {
+            _session = session;
+            _origState = session.State;
+            _newState = newState;
+            _session.ChangeState(newState, false);
+        }
+
+        #region ICommitable Members
+
+        public void Commit()
+        {
+            if (_session.State == _newState)
+            {
+                _session.ChangeState(_newState, true);
+            }
+            _commit = true;
+        }
+
+        #endregion
+
+        #region IDisposable Members
+
+        public void Dispose()
+        {
+            if (!_commit && _session.State == _newState)
+            {
+                _session.ChangeState(_origState, false);
+            }
+        }
+
+        #endregion
+    }
+}