PromptPointOptions 类的疑惑，问题在代码第51行

mrhvslisp

1. /*代码来自CAD.net开发人员手册,
   
2. 本例提示用户输入五个点，然后根据输入的点创建多段线。该多段线是闭合的，所形成的面积显示在消息框中。因为多段线不需要添加到块中，所以在命令结束前需要删除它。问题在代码第51行*/
   
   
3. using Autodesk.AutoCAD.ApplicationServices;
   
4. using Autodesk.AutoCAD.DatabaseServices;
   
5. using Autodesk.AutoCAD.Geometry;
   
6. using Autodesk.AutoCAD.EditorInput;
   
7. using Autodesk.AutoCAD.Runtime;
   
8. 
   
9. [CommandMethod("CalculateDefinedArea")]
   
10. public static void CalculateDefinedArea()
    
11. {
    
12.   // 提示用户输入 5 个点    Prompt the user for 5 points
    
13.   Document acDoc = Application.DocumentManager.MdiActiveDocument;
    
14. 
    
15.   PromptPointResult pPtRes;
    
16.   Point2dCollection colPt = new Point2dCollection();
    
17.   PromptPointOptions pPtOpts = new PromptPointOptions("");
    
18. 
    
19.   // 提示输入第一个点   Prompt for the first point
    
20.   pPtOpts.Message = "\nSpecify first point: ";
    
21.   pPtRes = acDoc.Editor.GetPoint(pPtOpts);
    
22.   colPt.Add(new Point2d(pPtRes.Value.X, pPtRes.Value.Y));
    
23. 
    
24.   // 如果用户按了 ESC 键或取消了命令就退出   Exit if the user presses ESC or cancels the command
    
25.   if (pPtRes.Status == PromptStatus.Cancel) return;
    
26. 
    
27.   int nCounter = 1;
    
28. 
    
29.   while (nCounter <= 4)
    
30.   {
    
31.       // 提示指定下一个点   Prompt for the next points
    
32.       switch(nCounter)
    
33.       {
    
34.           case 1:
    
35.               pPtOpts.Message = "\nSpecify second point: ";
    
36.               break;
    
37.           case 2:
    
38.               pPtOpts.Message = "\nSpecify third point: ";
    
39.               break;
    
40.           case 3:
    
41.               pPtOpts.Message = "\nSpecify fourth point: ";
    
42.               break;
    
43.           case 4:
    
44.               pPtOpts.Message = "\nSpecify fifth point: ";
    
45.               break;
    
46.       }
    
47. 
    
48.       // 使用前一个点作为基点   Use the previous point as the base point
    
49.       pPtOpts.UseBasePoint = true;
    
50.       pPtOpts.BasePoint = pPtRes.Value;
    
51.      //问题在这里，UseBasePoint 和BasePoint 属性指的是什么？请指教。
    
52.       pPtRes = acDoc.Editor.GetPoint(pPtOpts);
    
53.       colPt.Add(new Point2d(pPtRes.Value.X, pPtRes.Value.Y));
    
54. 
    
55.       if (pPtRes.Status == PromptStatus.Cancel) return;
    
56. 
    
57.       // 递增计数器    Increment the counter
    
58.       nCounter = nCounter + 1;
    
59.   }
    
60. 
    
61.   // 用5个点创建多段线   Create a polyline with 5 points
    
62.   using (Polyline acPoly = new Polyline())
    
63.   {
    
64.       acPoly.AddVertexAt(0, colPt[0], 0, 0, 0);
    
65.       acPoly.AddVertexAt(1, colPt[1], 0, 0, 0);
    
66.       acPoly.AddVertexAt(2, colPt[2], 0, 0, 0);
    
67.       acPoly.AddVertexAt(3, colPt[3], 0, 0, 0);
    
68.       acPoly.AddVertexAt(4, colPt[4], 0, 0, 0);
    
69. 
    
70.       // 闭合多段线   Close the polyline
    
71.       acPoly.Closed = true;
    
72. 
    
73.       // 查询多段线的面积   Query the area of the polyline
    
74.       Application.ShowAlertDialog("Area of polyline: " +
    
75.                                   acPoly.Area.ToString());
    
76. 
    
77.       // 销毁多段线   Dispose of the polyline
    
78.   }
    
79. }
    

/*代码来自CAD.net开发人员手册,<br /> <div align="left">本例提示用户输入五个点，然后根据输入的点创建多段线。该多段线是闭合的，所形成的面积显示在消息框中。因为多段线不需要添加到块中，所以在命令结束前需要删除它。问题在代码第51行*/</div><br /> using Autodesk.<a href="http://bbs.mjtd.com/forum-41-1.html" target="_blank" class="relatedlink">AutoCAD</a>.ApplicationServices;<br /> using Autodesk.AutoCAD.DatabaseServices;<br /> using Autodesk.AutoCAD.Geometry;<br /> using Autodesk.AutoCAD.EditorInput;<br /> using Autodesk.AutoCAD.Runtime;<br /> <br /> [CommandMethod("CalculateDefinedArea")]<br /> public static void CalculateDefinedArea()<br /> {<br />   // 提示用户输入 5 个点    Prompt the user for 5 points<br />   Document acDoc = Application.DocumentManager.MdiActiveDocument;<br /> <br />   PromptPointResult pPtRes;<br />   Point2dCollection colPt = new Point2dCollection();<br />   PromptPointOptions pPtOpts = new PromptPointOptions("");<br /> <br />   // 提示输入第一个点   Prompt for the first point<br />   pPtOpts.Message = "\nSpecify first point: ";<br />   pPtRes = acDoc.Editor.GetPoint(pPtOpts);<br />   colPt.Add(new Point2d(pPtRes.Value.X, pPtRes.Value.Y));<br /> <br />   // 如果用户按了 ESC 键或取消了命令就退出   Exit if the user presses ESC or cancels the command<br />   if (pPtRes.Status == PromptStatus.Cancel) return;<br /> <br />   int nCounter = 1;<br /> <br />   while (nCounter <= 4)<br />   {<br />       // 提示指定下一个点   Prompt for the next points<br />       switch(nCounter)<br />       {<br />           case 1:<br />               pPtOpts.Message = "\nSpecify second point: ";<br />               break;<br />           case 2:<br />               pPtOpts.Message = "\nSpecify third point: ";<br />               break;<br />           case 3:<br />               pPtOpts.Message = "\nSpecify fourth point: ";<br />               break;<br />           case 4:<br />               pPtOpts.Message = "\nSpecify fifth point: ";<br />               break;<br />       }<br /> <br />       // 使用前一个点作为基点   Use the previous point as the base point<br />       pPtOpts.UseBasePoint = true;<br />       pPtOpts.BasePoint = pPtRes.Value;<br />      //问题在这里，UseBasePoint 和BasePoint 属性指的是什么？请指教。<br />       pPtRes = acDoc.Editor.GetPoint(pPtOpts);<br />       colPt.Add(new Point2d(pPtRes.Value.X, pPtRes.Value.Y));<br /> <br />       if (pPtRes.Status == PromptStatus.Cancel) return;<br /> <br />       // 递增计数器    Increment the counter<br />       nCounter = nCounter + 1;<br />   }<br /> <br />   // 用5个点创建多段线   Create a polyline with 5 points<br />   using (Polyline acPoly = new Polyline())<br />   {<br />       acPoly.AddVertexAt(0, colPt[0], 0, 0, 0);<br />       acPoly.AddVertexAt(1, colPt[1], 0, 0, 0);<br />       acPoly.AddVertexAt(2, colPt[2], 0, 0, 0);<br />       acPoly.AddVertexAt(3, colPt[3], 0, 0, 0);<br />       acPoly.AddVertexAt(4, colPt[4], 0, 0, 0);<br /> <br />       // 闭合多段线   Close the polyline<br />       acPoly.Closed = true;<br /> <br />       // 查询多段线的面积   Query the area of the polyline<br />       Application.ShowAlertDialog("Area of polyline: " +<br />                                   acPoly.Area.ToString());<br /> <br />       // 销毁多段线   Dispose of the polyline<br />   }<br /> }<br />

yanglin112

楼主把49行以为
pPtOpts.UseBasePoint = false;
再运行一下就能看差别了,以一点为基点，到鼠标点取下一点之前会有从基点到光标处的一条直线，有点儿像拖拽的效果！

ctgu123

飘过学习了~