致力于图形处理和移动开发。
分类: C#/.net
2014-05-14 11:20:25
最近一直有网友在问,在使用的过程中如何在用户执行一个新的动作之后清空重做栈。有两种方法可以实现这一点。
方案一
vdFramedControl1.BaseControl.ActiveDocument.UndoHistory.OnStoreValue += new VectorDraw.Professional.UndoRedo.ModificationHistory.StoreValueEventHandler(UndoHistory_OnStoreValue); Add this function as the event handler: bool whileRedo = false; void UndoHistory_OnStoreValue(object sender, bool isRedo, object propObject, string propName, object value, ref bool Cancel) { //We use this check to make sure that the new Undo value stored is not coming from a Redo command. if (!isRedo && !whileRedo) vdFramedControl1.BaseControl.ActiveDocument.UndoHistory.ClearRedoStack(); } Also get this event in order to override the functionality of Redo: vdFramedControl1.CommandLine.CommandExecute += new VectorDraw.Professional.vdCommandLine.CommandExecuteEventHandler(CommandLine_CommandExecute); Add this function to handle the above event: void CommandLine_CommandExecute(string commandname, bool isDefaultImplemented, ref bool success) { //Here we override the Redo command in order to set the whileRedo function to true. That way we will know if the OnStoreValue event mentioned above is called due to a Redo function. if (string.Compare(commandname, "redo", true) == 0 || string.Compare(commandname, "r", true) == 0) { success = true; doc.CommandAction.Prompt("\r\n" + commandname); doc.CommandAction.Prompt(null); whileRedo = true; doc.UndoHistory.Redo(); whileRedo = false; doc.Update(); doc.Invalidate(); } }
使用上述代码后,每次修改对象属性,或添加一个创建undo值的新对象,重做堆栈将被清除。这样的话,在用户新增一个项目或修改一个属性后,无需 Redoing 选项。
方案二
vdFramedControl1.CommandLine.CommandExecute += new VectorDraw.Professional.vdCommandLine.CommandExecuteEventHandler(CommandLine_CommandExecute); Add this function to handle the above event: void CommandLine_CommandExecute(string commandname, bool isDefaultImplemented, ref bool success) { //Here we override every command after which we want the Redo stack cleared if (string.Compare(commandname, "line", true) == 0 || string.Compare(commandname, "l", true) == 0 || string.Compare(commandname, "rect", true) == 0 || string.Compare(commandname, "move", true) == 0) { //Don't set success to true, so that the execution of already implemented commands won't stop after this function! vdFramedControl1.BaseControl.ActiveDocument.UndoHistory.ClearRedoStack(); doc.Update(); doc.Invalidate(); } }
使用上述代码后,每次使用的矩形或移动命令时,重做堆栈都将被清除。