What's the best way to iterate through an entire Database?

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What's the best way to iterate through an entire Database?                                                        By Philippe Leefsma
  The objects stored in the database get an handle value that gets incremented sequentially, so the fastest approach if one wants to iterate through the whole content of a Database, is to start from handle = 1 to the max handle existing in the Database. P/Invoking "acdbHandEnt" can then help to retrieve the ObjectId from an handle.
  The following C# code illustrates how to do that:

2. public struct ads_name
   
3. {
   
4.     public IntPtr a;
   
5.     public IntPtr b;
   
6. };
   
7. 
   
8. [DllImport("acdb19.dll",
   
9. CharSet = CharSet.Unicode,
   
10. CallingConvention = CallingConvention.Cdecl,
    
11. EntryPoint = "acdbHandEnt")]
    
12. public static extern int acdbHandEnt(
    
13.     string handle, ref ads_name name);
    
14. 
    
15. [CommandMethod("IterateDb")]
    
16. static public void IterateDb()
    
17. {
    
18.     ads_name ename = new ads_name();
    
19.     Document doc = Application.DocumentManager.MdiActiveDocument;
    
20.     Database db = doc.Database;
    
21.     Editor ed = doc.Editor;
    
22.     ObjectIdCollection validIds = new ObjectIdCollection();
    
23.     // now get the last handle in the db
    
24.     Handle handseed = db.Handseed;
    
25.     // copy the handseed total into an efficient raw datatype
    
26.     long handseedTotal = handseed.Value;
    
27.     // loop from 0 to the last handle (this could be a big loop)
    
28.     for (long i = 1; i < handseedTotal; ++i)
    
29.     {
    
30.         string handle = Convert.ToString(i, 16);
    
31.         // get the ename by converting
    
32.         // the long to a hex value string
    
33.         int res = acdbHandEnt(handle, ref ename);
    
34.         if (res != 5100) // RTNORM
    
35.             continue;
    
36.         // convert the ename to an objectid
    
37.         ObjectId id = new ObjectId(ename.a);
    
38.         // check if it's a valid objectId
    
39.         if (!id.IsValid)
    
40.             continue;
    
41.         try
    
42.         {
    
43.             // open if not erased
    
44.             using (DBObject obj =
    
45.                 id.Open(OpenMode.ForRead, false))
    
46.             {
    
47.                 validIds.Add(id);
    
48.             }
    
49.         }
    
50.         catch
    
51.         {
    
52. 
    
53.         }
    
54.     }
    
55.     ed.WriteMessage("\nNumber of retrieved valid ObjectIds: "
    
56.         + validIds.Count.ToString());
    
57.     validIds.Clear();
    
58. 
    
59. }

public struct ads_name<br /> {<br />     public IntPtr a;<br />     public IntPtr b;<br /> }; <br /> <br /> [DllImport("acdb19.dll",<br /> CharSet = CharSet.Unicode,<br /> CallingConvention = CallingConvention.Cdecl,<br /> EntryPoint = "acdbHandEnt")]<br /> public static extern int acdbHandEnt(<br />     string handle, ref ads_name name); <br /> <br /> [CommandMethod("IterateDb")]<br /> static public void IterateDb()<br /> {<br />     ads_name ename = new ads_name();<br />     Document doc = Application.DocumentManager.MdiActiveDocument;<br />     Database db = doc.Database;<br />     Editor ed = doc.Editor;<br />     ObjectIdCollection validIds = new ObjectIdCollection();<br />     // now get the last handle in the db<br />     Handle handseed = db.Handseed;<br />     // copy the handseed total into an efficient raw datatype<br />     long handseedTotal = handseed.Value;<br />     // loop from 0 to the last handle (this could be a big loop)<br />     for (long i = 1; i < handseedTotal; ++i)<br />     {<br />         string handle = Convert.ToString(i, 16);<br />         // get the ename by converting<br />         // the long to a hex value string<br />         int res = acdbHandEnt(handle, ref ename);<br />         if (res != 5100) // RTNORM<br />             continue;<br />         // convert the ename to an objectid<br />         ObjectId id = new ObjectId(ename.a);<br />         // check if it's a valid objectId<br />         if (!id.IsValid)<br />             continue;<br />         try<br />         {<br />             // open if not erased<br />             using (DBObject obj =<br />                 id.Open(OpenMode.ForRead, false))<br />             {<br />                 validIds.Add(id);<br />             }<br />         }<br />         catch<br />         {<br /> <br />         }<br />     }<br />     ed.WriteMessage("\nNumber of retrieved valid ObjectIds: "<br />         + validIds.Count.ToString()); <br />     validIds.Clear();<br /> <br /> }