CAD二次开发（9）- CAD中对象的实时选择

1. 点的拾取

有时候我们需要在CAD画布上实时选取起始点和结束点，然后绘制出来一条直线。实现如下：

public void getPoint(){var doc = Application.DocumentManager.MdiActiveDocument;var editor = doc.Editor;var docDatabase = doc.Database;PromptPointOptions ppo = new PromptPointOptions("拾取线段起点：");//获取线段起点的输入PromptPointResult pointResult = editor.GetPoint(ppo);var start = pointResult.Value;//基点到光标的虚线标识ppo.BasePoint = start;ppo.UseBasePoint=true;ppo.UseDashedLine=true;//如果用户设置了起始节点，再让用户获取结束节点if (pointResult.Status == PromptStatus.OK){ppo.Message = "拾取线段终点：";pointResult = editor.GetPoint(ppo);var end = pointResult.Value;if (pointResult.Status == PromptStatus.OK){//方式一：绘制临时向量，并不存储到数据库中// editor.DrawVector(start,end,1,false);//方式二：提交到数据库docDatabase.AddEnityToModelSpace(new Line(start, end));}}}

AddEnityToModelSpace方法见我前面文章封装的工具类

效果如下：
在这里插入图片描述

2. 角度的拾取

 public void getAngle(){var editor = Application.DocumentManager.MdiActiveDocument.Editor;PromptAngleOptions pao = new PromptAngleOptions("拾取角度：");pao.AllowNone = false;pao.UseDashedLine = true;pao.UseAngleBase=false;PromptDoubleResult startAngle = editor.GetAngle(pao);if (startAngle.Status == PromptStatus.OK){editor.WriteMessage("\n角度：{0}", startAngle.Value);}}

最终效果：
在这里插入图片描述

3. 单个实体对象的拾取

public void getOneEntity(){var doc = Application.DocumentManager.MdiActiveDocument;Editor editor = doc.Editor;PromptEntityResult per = editor.GetEntity("\n拾取任意实体：");if (per.Status == PromptStatus.OK){var perObjectId = per.ObjectId;using (Transaction ts = doc.Database.TransactionManager.StartTransaction()){var entity = (Entity)ts.GetObject(perObjectId, OpenMode.ForRead,true);editor.WriteMessage("\n拾取实体对象：{0},类型：{1}", entity.ToString(),entity.GetType().FullName);ts.Commit();}}}

4. 特定实体对象的拾取

利用过滤器进行选择。

 public void getSpecificEntity(){var doc = Application.DocumentManager.MdiActiveDocument;Editor editor = doc.Editor;PromptEntityOptions peo = new PromptEntityOptions("\n拾取线条：");peo.SetRejectMessage("\n 选择的对象类型不是线条，请重新选择！");peo.AddAllowedClass(typeof(Line), true);PromptEntityResult per = editor.GetEntity(peo);if (per.Status == PromptStatus.OK){var perObjectId = per.ObjectId;using (Transaction ts = doc.Database.TransactionManager.StartTransaction()){var entity = (Entity)ts.GetObject(perObjectId, OpenMode.ForRead,true);editor.WriteMessage("\n拾取实体对象：{0},类型：{1}", entity.ToString(),entity.GetType().FullName);ts.Commit();}}}

5. 利用选择集拾取多个实体对象

/// <summary>/// 利用选择集选择多个实体对象/// </summary>[CommandMethod("selectEntities")]public void selectEntitiesTest(){List<Entity> entities = selectEntities();}public List<Entity> selectEntities(){var doc = Application.DocumentManager.MdiActiveDocument;Editor editor = doc.Editor;var docDatabase = doc.Database;SelectionSet selectionSet;//清空选择集var objectIds = new ObjectId[0];editor.SetImpliedSelection(objectIds);//请求从图形区域选择对象PromptSelectionResult psr = editor.GetSelection();if (psr.Status == PromptStatus.OK){selectionSet = psr.Value;var objectIdList = selectionSet.GetObjectIds().ToList();List<Entity> entities = new List<Entity>();using (Transaction tr = docDatabase.TransactionManager.StartTransaction()){foreach (var objectId in objectIdList){var entity = (Entity)objectId.GetObject(OpenMode.ForRead);entities.Add(entity);}tr.Commit();return entities;}}return null;}