CAD 开发小技巧

1.  C#计算两点之间的距离.(09.10.7)

  1    Point2d p0,p1;

      double d1 = p1.GetDistanceTo(p0);

2     (p1-p0).Length 两点相减得到一个向量.再得到距离.

2.  Vector2d 和 Vector3d 类

可以获得该向量的长度.是否垂直/平行另个向量.

 

3.用矩形框选择两个点

      PromptCornerOptions pco = new PromptCornerOptions("\nSelect second corner of plot area: ", first);

            ppr = ed.GetCorner(pco);

             if (ppr.Status != PromptStatus.OK)

                return;

             Point3d second = ppr.Value;

4.    选择 块中的对象.Gets the name of an entity selected by the user using the supplied prompt selection options.

  ObjectId i=  ed.GetNestedEntity("PromptString").ObjectId;

5. PromptForSelectionEnding 事件.可以获得选择的对象

 

      privatevoidcallback_PromptForSelectionEnding(objectsender, PromptForSelectionEndingEventArgse)

      {

         try

         {

            WriteLine(String.Format("PromptForSelectionEnding - ssCount:{0}", e.Selection.Count));

         }

         catch (System.Exceptionex)

         {

            Helper.Message(ex);

         }

      }

6.获得坐标点.

                Tools.WriteMessage("computedPoint:"+e.Context.ComputedPoint.ToString()+e.Context.PointComputed.ToString()+"\n");//包括跟踪点

                Tools.WriteMessage("lastPoint:"+ e.Context.LastPoint.ToString()+"\n");//最后一点.

                Tools.WriteMessage("RawPoint:" + e.Context.RawPoint.ToString() + "\n");//光标所在的坐标点

7.

           #region LINQ资料

                           每类产品，价格之和

                varq =

                    frompindb.Products

                    grouppbyp.CategoryIDintog

                    selectnew {

                        g.Key,

                        TotalPrice = g.Sum(p => p.UnitPrice)

                    };

 

8.只有当实体加入到图形空间.才可以用ent.GeometricExtents属性

 

9. ent.IsNewObject 判断Ent是一个新对对象.也就是是否已经加入数据库