C# UndoRedoRecorder.BeginActionGroup方法代码示例

        /// <summary>
        /// TODO(Ben): This method is exposed this way for external codes (e.g. 
        /// the DragCanvas) to record models before they are modified. This is 
        /// by no means ideal. The ideal case of course is for ALL codes that 
        /// end up modifying models to be folded back into WorkspaceViewModel in 
        /// the form of commands. These commands then internally record those
        /// affected models before updating them. We need this method to be gone
        /// sooner than later.
        /// </summary>
        /// <param name="models">The models to be recorded for undo.</param>
        /// <param name="recorder"></param>
        internal static void RecordModelsForModification(List<ModelBase> models, UndoRedoRecorder recorder)
        {
            if (null == recorder)
                return;
            if (!ShouldProceedWithRecording(models))
                return;

            using (recorder.BeginActionGroup())
            {
                foreach (var model in models)
                    recorder.RecordModificationForUndo(model);
            }
        }

        internal static void RecordModelsForUndo(Dictionary<ModelBase, UndoRedoRecorder.UserAction> models, UndoRedoRecorder recorder)
        {
            if (null == recorder)
                return;
            if (!ShouldProceedWithRecording(models))
                return;

            using (recorder.BeginActionGroup())
            {
                foreach (var modelPair in models)
                {
                    switch (modelPair.Value)
                    {
                        case UndoRedoRecorder.UserAction.Creation:
                            recorder.RecordCreationForUndo(modelPair.Key);
                            break;
                        case UndoRedoRecorder.UserAction.Deletion:
                            recorder.RecordDeletionForUndo(modelPair.Key);
                            break;
                        case UndoRedoRecorder.UserAction.Modification:
                            recorder.RecordModificationForUndo(modelPair.Key);
                            break;
                    }
                }
            }
        }

        private void CommitChanges(UndoRedoRecorder recorder)
        {
            // Code block editor can lose focus in many scenarios (e.g. switching 
            // of tabs or application), if there has not been any changes, do not
            // commit the change.
            // 
            if (!nodeModel.Code.Equals(InnerTextEditor.Text))
            {
                nodeViewModel.DynamoViewModel.ExecuteCommand(
                    new DynCmd.UpdateModelValueCommand(
                        nodeViewModel.WorkspaceViewModel.Model.Guid,
                        nodeModel.GUID,
                        "Code", InnerTextEditor.Text));
            }

            if (createdForNewCodeBlock)
            {
                // If this editing was started due to a new code block node, 
                // then by this point there would have been two action groups 
                // recorded on the undo-stack: one for node creation, and 
                // another for node editing (as part of ExecuteCommand above).
                // Pop off the two action groups...
                // 
                recorder.PopFromUndoGroup(); // Pop off modification action.

                // Note that due to various external factors a code block node 
                // loaded from file may be created empty. In such cases, the 
                // creation step would not have been recorded (there was no 
                // explicit creation of the node, it was created from loading 
                // of a file), and nothing should be popped off of the undo stack.
                if (recorder.CanUndo)
                    recorder.PopFromUndoGroup(); // Pop off creation action.

                // ... and record this new node as new creation.
                using (recorder.BeginActionGroup())
                {
                    recorder.RecordCreationForUndo(nodeModel);
                }
            }
        }