Iterating AutoCAD system variables using .NET – Part 1

csharp

http://through-the-interface.typepad.com/through_the_interface/2014/06/iterating-autocad-system-variables-using-net-part-1.html

On my flight across to Toronto, I took another look at the “What’s New in AutoCAD 2015” section of the .NET API documentation and decided to dig into the new SystemVariableEnumerator implementation.
I was particularly curious about this feature as there is already a way to get access to system variables via the Autodesk.AutoCAD.Runtime.SystemObjects.Variables collection. As an initial look at these two classes, I decided to put together a couple of simple variable iterator commands that use the same function to print out some information concerning the system variables exposed by each collection.
Here’s the C# code implementing two commands, ESV and ESV2, which use the two mechanisms for getting the list of AutoCAD system variables:


We won’t look at the output to the command-line in this post, as there’s a lot there. Hopefully the format of the data printed to the command-line is obvious from the code.
A big chunk of this code actually “decodes” the type information, returning a System.Type object when it can make sense of the number passed in (which may be a 50xx number or a shorter enumeration, depending on which mechanism has been used).
It’s also worth noting that it wasn’t quite as simple as doing a “foreach” on the new API: it seems there’s a GetEnumerator() method missing which means we can’t simplify our code in that way, unfortunately (hence the long-hand approach using MoveNext() etc.). Hopefully someone will tell me I’ve made a mistake somewhere in my code and that it is, in fact, possible. :-)
The newer enumerator skips over “hidden” system variables – those with an asterisk (“*”) prefix on their name – which do get returned as part of the SystemObjects collection.
The SystemObjects collection does allow you to set the value of a variable, which is pretty interesting. In a future post we’ll take a look at this capability as well as comparing the performance of the two mechanisms, to see which is most efficient

2. 
   
3. using Autodesk.AutoCAD.ApplicationServices;
   
4. 
   
5. using Autodesk.AutoCAD.ApplicationServices.Core;
   
6. 
   
7. using Autodesk.AutoCAD.EditorInput;
   
8. 
   
9. using Autodesk.AutoCAD.Geometry;
   
10. 
    
11. using Autodesk.AutoCAD.Runtime;
    
12. 
    
13. using System;
    
14. 
    
15. 
    
16. 
    
17. namespace SystemVariableEnumeration
    
18. 
    
19. {
    
20. 
    
21.   public class Commands
    
22. 
    
23.   {
    
24. 
    
25.     [CommandMethod("ESV")]
    
26. 
    
27.     public static void EnumerateSysVars()
    
28. 
    
29.     {
    
30. 
    
31.       var doc = Application.DocumentManager.MdiActiveDocument;
    
32. 
    
33.       if (doc == null)
    
34. 
    
35.         return;
    
36. 
    
37.       var ed = doc.Editor;
    
38. 
    
39. 
    
40. 
    
41.       // Use the existing SystemObjects iteration mechanism
    
42. 
    
43. 
    
44. 
    
45.       foreach (var v in SystemObjects.Variables)
    
46. 
    
47.       {
    
48. 
    
49.         PrintVariable(ed, v);
    
50. 
    
51.       }
    
52. 
    
53.     }
    
54. 
    
55. 
    
56. 
    
57.     [CommandMethod("ESV2")]
    
58. 
    
59.     public static void EnumerateSysVars2()
    
60. 
    
61.     {
    
62. 
    
63.       var doc = Application.DocumentManager.MdiActiveDocument;
    
64. 
    
65.       if (doc == null)
    
66. 
    
67.         return;
    
68. 
    
69.       var ed = doc.Editor;
    
70. 
    
71. 
    
72. 
    
73.       // Use the new system variable enumerator
    
74. 
    
75. 
    
76. 
    
77.       var sve = new SystemVariableEnumerator();
    
78. 
    
79. 
    
80. 
    
81.       while (sve.MoveNext())
    
82. 
    
83.       {
    
84. 
    
85.         var v = sve.Current;
    
86. 
    
87.         if (v != null)
    
88. 
    
89.         {
    
90. 
    
91.           PrintVariable(ed, v);
    
92. 
    
93.         }
    
94. 
    
95.       }
    
96. 
    
97.     }
    
98. 
    
99. 
    
100. 
     
101.     // Helper function to print out the information about
     
102. 
     
103.     // a particular variable
     
104. 
     
105. 
     
106. 
     
107.     private static void PrintVariable(Editor ed, Variable v)
     
108. 
     
109.     {
     
110. 
     
111.       var t = GetType(v.PrimaryType);
     
112. 
     
113. 
     
114. 
     
115.       ed.WriteMessage(
     
116. 
     
117.         "\n{0} ({1}, {2} - {3}): {4}",
     
118. 
     
119.         v.Name,
     
120. 
     
121.         t == null ? "null" : t.Name,
     
122. 
     
123.         v.PrimaryType, v.SecondaryType, v.TypeFlags
     
124. 
     
125.       );
     
126. 
     
127. 
     
128. 
     
129.       if (v.Range != null)
     
130. 
     
131.       {
     
132. 
     
133.         ed.WriteMessage(
     
134. 
     
135.           " [{0}...{1}]",
     
136. 
     
137.           v.Range.LowerBound, v.Range.UpperBound
     
138. 
     
139.         );
     
140. 
     
141.       }
     
142. 
     
143.     }
     
144. 
     
145. 
     
146. 
     
147.     // Determine the type of a system variable based on
     
148. 
     
149.     // the internal representation
     
150. 
     
151. 
     
152. 
     
153.     private static System.Type GetType(short v)
     
154. 
     
155.     {
     
156. 
     
157.       Type ret = null;
     
158. 
     
159. 
     
160. 
     
161.       switch (v)
     
162. 
     
163.       {
     
164. 
     
165.         case 1:
     
166. 
     
167.         case 5001: // RTREAL real number
     
168. 
     
169.           {
     
170. 
     
171.             ret = typeof(Double);
     
172. 
     
173.             break;
     
174. 
     
175.           }
     
176. 
     
177.         case 2:
     
178. 
     
179.         case 5002: // RTPOINT: 2D point X and Y only
     
180. 
     
181.           {
     
182. 
     
183.             ret = typeof(Point2d);
     
184. 
     
185.             break;
     
186. 
     
187.           }
     
188. 
     
189.         case 3:
     
190. 
     
191.         case 5003: // RTSHORT: short integer
     
192. 
     
193.           {
     
194. 
     
195.             ret = typeof(Int16);
     
196. 
     
197.             break;
     
198. 
     
199.           }
     
200. 
     
201.         case 4:
     
202. 
     
203.         case 5004: // RTANG: angle
     
204. 
     
205.           {
     
206. 
     
207.             ret = null; // Angle
     
208. 
     
209.             break;
     
210. 
     
211.           }
     
212. 
     
213.         case 5:
     
214. 
     
215.         case 5005: // RTSTR: string
     
216. 
     
217.           {
     
218. 
     
219.             ret = typeof(String);
     
220. 
     
221.             break;
     
222. 
     
223.           }
     
224. 
     
225.         case 6:
     
226. 
     
227.         case 5006: // RTENAME: entity name
     
228. 
     
229.           {
     
230. 
     
231.             ret = null;
     
232. 
     
233.             break;
     
234. 
     
235.           }
     
236. 
     
237.         case 7:
     
238. 
     
239.         case 5007: // RTPICKS: pick set
     
240. 
     
241.           {
     
242. 
     
243.             ret = null;
     
244. 
     
245.             break;
     
246. 
     
247.           }
     
248. 
     
249.         case 8:
     
250. 
     
251.         case 5008: // RTORIENT: orientation
     
252. 
     
253.           {
     
254. 
     
255.             ret = null; // Orientation
     
256. 
     
257.             break;
     
258. 
     
259.           }
     
260. 
     
261.         case 9:
     
262. 
     
263.         case 5009: // RT3DPOINT: 3D point - X, Y and Z
     
264. 
     
265.           {
     
266. 
     
267.             ret = typeof(Point3d);
     
268. 
     
269.             break;
     
270. 
     
271.           }
     
272. 
     
273.         case 10:
     
274. 
     
275.         case 5010: // RTLONG: long integer
     
276. 
     
277.           {
     
278. 
     
279.             ret = typeof(Int32);
     
280. 
     
281.             break;
     
282. 
     
283.           }
     
284. 
     
285.         case 11:
     
286. 
     
287.         case 5011: // 2D extents of some kind
     
288. 
     
289.           {
     
290. 
     
291.             ret = typeof(Point2d);
     
292. 
     
293.             break;
     
294. 
     
295.           }
     
296. 
     
297.       }
     
298. 
     
299.       return ret;
     
300. 
     
301.     }
     
302. 
     
303.   }
     
304. 
     
305. }
     

<br /> using Autodesk.AutoCAD.ApplicationServices;<br /> <br /> using Autodesk.AutoCAD.ApplicationServices.Core;<br /> <br /> using Autodesk.AutoCAD.EditorInput;<br /> <br /> using Autodesk.AutoCAD.Geometry;<br /> <br /> using Autodesk.AutoCAD.Runtime;<br /> <br /> using System;<br /> <br /> <br /> <br /> namespace SystemVariableEnumeration<br /> <br /> {<br /> <br />   public class Commands<br /> <br />   {<br /> <br />     [CommandMethod("ESV")]<br /> <br />     public static void EnumerateSysVars()<br /> <br />     {<br /> <br />       var doc = Application.DocumentManager.MdiActiveDocument;<br /> <br />       if (doc == null)<br /> <br />         return;<br /> <br />       var ed = doc.Editor;<br /> <br /> <br /> <br />       // Use the existing SystemObjects iteration mechanism<br /> <br /> <br /> <br />       foreach (var v in SystemObjects.Variables)<br /> <br />       {<br /> <br />         PrintVariable(ed, v);<br /> <br />       }<br /> <br />     }<br /> <br /> <br /> <br />     [CommandMethod("ESV2")]<br /> <br />     public static void EnumerateSysVars2()<br /> <br />     {<br /> <br />       var doc = Application.DocumentManager.MdiActiveDocument;<br /> <br />       if (doc == null)<br /> <br />         return;<br /> <br />       var ed = doc.Editor;<br /> <br /> <br /> <br />       // Use the new system variable enumerator<br /> <br /> <br /> <br />       var sve = new SystemVariableEnumerator();<br /> <br /> <br /> <br />       while (sve.MoveNext())<br /> <br />       {<br /> <br />         var v = sve.Current;<br /> <br />         if (v != null)<br /> <br />         {<br /> <br />           PrintVariable(ed, v);<br /> <br />         }<br /> <br />       }<br /> <br />     }<br /> <br /> <br /> <br />     // Helper function to print out the information about<br /> <br />     // a particular variable<br /> <br /> <br /> <br />     private static void PrintVariable(Editor ed, Variable v)<br /> <br />     {<br /> <br />       var t = GetType(v.PrimaryType);<br /> <br /> <br /> <br />       ed.WriteMessage(<br /> <br />         "\n{0} ({1}, {2} - {3}): {4}",<br /> <br />         v.Name,<br /> <br />         t == null ? "null" : t.Name,<br /> <br />         v.PrimaryType, v.SecondaryType, v.TypeFlags<br /> <br />       );<br /> <br /> <br /> <br />       if (v.Range != null)<br /> <br />       {<br /> <br />         ed.WriteMessage(<br /> <br />           " [{0}...{1}]",<br /> <br />           v.Range.LowerBound, v.Range.UpperBound<br /> <br />         );<br /> <br />       }<br /> <br />     }<br /> <br /> <br /> <br />     // Determine the type of a system variable based on<br /> <br />     // the internal representation<br /> <br /> <br /> <br />     private static System.Type GetType(short v)<br /> <br />     {<br /> <br />       Type ret = null;<br /> <br /> <br /> <br />       switch (v)<br /> <br />       {<br /> <br />         case 1:<br /> <br />         case 5001: // RTREAL real number<br /> <br />           {<br /> <br />             ret = typeof(Double);<br /> <br />             break;<br /> <br />           }<br /> <br />         case 2:<br /> <br />         case 5002: // RTPOINT: 2D point X and Y only<br /> <br />           {<br /> <br />             ret = typeof(Point2d);<br /> <br />             break;<br /> <br />           }<br /> <br />         case 3:<br /> <br />         case 5003: // RTSHORT: short integer<br /> <br />           {<br /> <br />             ret = typeof(Int16);<br /> <br />             break;<br /> <br />           }<br /> <br />         case 4:<br /> <br />         case 5004: // RTANG: angle<br /> <br />           {<br /> <br />             ret = null; // Angle<br /> <br />             break;<br /> <br />           }<br /> <br />         case 5:<br /> <br />         case 5005: // RTSTR: string<br /> <br />           {<br /> <br />             ret = typeof(String);<br /> <br />             break;<br /> <br />           }<br /> <br />         case 6:<br /> <br />         case 5006: // RTENAME: entity name<br /> <br />           {<br /> <br />             ret = null;<br /> <br />             break;<br /> <br />           }<br /> <br />         case 7:<br /> <br />         case 5007: // RTPICKS: pick set<br /> <br />           {<br /> <br />             ret = null;<br /> <br />             break;<br /> <br />           }<br /> <br />         case 8:<br /> <br />         case 5008: // RTORIENT: orientation<br /> <br />           {<br /> <br />             ret = null; // Orientation<br /> <br />             break;<br /> <br />           }<br /> <br />         case 9:<br /> <br />         case 5009: // RT3DPOINT: 3D point - X, Y and Z<br /> <br />           {<br /> <br />             ret = typeof(Point3d);<br /> <br />             break;<br /> <br />           }<br /> <br />         case 10:<br /> <br />         case 5010: // RTLONG: long integer<br /> <br />           {<br /> <br />             ret = typeof(Int32);<br /> <br />             break;<br /> <br />           }<br /> <br />         case 11:<br /> <br />         case 5011: // 2D extents of some kind<br /> <br />           {<br /> <br />             ret = typeof(Point2d);<br /> <br />             break;<br /> <br />           }<br /> <br />       }<br /> <br />       return ret;<br /> <br />     }<br /> <br />   }<br /> <br /> }<br />