Topic: Hatching Around Text with C# .Net

[deckeresq]

Hey all,

I've been searching for a few weeks now, but unfortunately haven't been able to find an answer to my question. I'm attempting to hatch an area and detect islands (and not hatch them -- the island will always be MTEXT). I saw http://www.theswamp.org/index.php?topic=38156.0#lastPost, but it always throws an Exception for me, as has every other similar piece of code I've found. I'm able to get the ObjectId of the MTEXT and the PLINE, but when I try to append the loop to multiple IDs, as follows:

Code - C#: [Select]

1. foreach (ObjectId id in ids) //ids is an ObjectIdCollection
2. {
3.     if (id != ObjectId.Null)
4.     {
5.         acHatch.AppendLoop(HatchLoopTypes.Outermost, new ObjectIdCollection() { id });
6.     }
7. }
8.  

I get an "InvalidInput" Exception on the second run of the loop. Here's the code that currently works, except that it hatches through text (coll only ever has 1 ObjectId):

Code - C#: [Select]

1. private void AddHatch(Transaction tr, BlockTableRecord acBlkTblRec, MaxHatch hatchCommand, ObjectIdCollection coll)
2.         {          
3.             try
4.             {
5.                 Hatch acHatch = new Hatch();
6.                 acHatch.SetDatabaseDefaults();
7.                 acHatch.SetHatchPattern(HatchPatternType.PreDefined, hatchCommand.HatchCode);
8.                 acHatch.HatchStyle = HatchStyle.Outer;
9.                 acHatch.ColorIndex = hatchCommand.HatchColor;
10.                 acHatch.PatternAngle = hatchCommand.HatchAngle;                        
11.                 acHatch.PatternScale = hatchCommand.HatchScale;                
12.  
13.                 //have to call SetHatchPattern again due to AutoCAD bug (http://forums.autodesk.com/t5/net/hatch-pattern-scale-problem/td-p/2057211), confirmed on http://adndevblog.typepad.com/autocad/2012/07/hatch-using-the-autocad-net-api.html
14.                 acHatch.SetHatchPattern(HatchPatternType.PreDefined, hatchCommand.HatchCode);
15.  
16.                 acBlkTblRec.AppendEntity(acHatch);
17.                 tr.AddNewlyCreatedDBObject(acHatch, true);
18.  
19.                 acHatch.Associative = true;
20.  
21.  
22.                 acHatch.AppendLoop(HatchLoopTypes.Outermost, coll);
23.  
24.                 acHatch.EvaluateHatch(true);
25.             }
26.             catch (System.Exception ex)
27.             {
28.                 HandleError("AddHatch", ex.Message, false);
29.             }
30.         }
31.  

Any ideas?

[MexicanCustard]

Without trying to run your code I can tell you how I did it.  I have a Polyline(polyline) around the area I want to hatch and a DBText(text) entity inside so first I create a Region(reg) from the Polyline.

Code - C#: [Select]

1. var tempcol = new DBObjectCollection { polyline };
2. var regions = Region.CreateFromCurves(tempcol);
3. var reg = (Region)regions[0];
4. reg.SetDatabaseDefaults();
5. modelSpace.AppendEntity(reg);
6. tr.AddNewlyCreatedDBObject(reg, true);

Then I create the Hatch(hat).

Code - C#: [Select]

1. var hat = new Hatch();
2. hat.SetDatabaseDefaults();
3. hat.SetHatchPattern(HatchPatternType.PreDefined, "ANSI31");
4. hat.Associative = false;
5. hat.AppendLoop(HatchLoopTypes.External, new ObjectIdCollection(new[] { reg.ObjectId }));  //Put the Hatch inside the polyline
6. hat.AppendLoop(HatchLoopTypes.Default, new ObjectIdCollection(new[] { text.ObjectId }));   //Let the Hatch know there are islands inside
7. modelSapce.AppendEntity(hat);
8. tr.AddNewlyCreatedDBObject(hat, true);

[deckeresq]

Thanks for the suggestion, MexicanCustard! Unfortunately, I get the same "eInvalidInput" Exception at this line:

Code - C#: [Select]

1. hat.AppendLoop(HatchLoopTypes.External, new ObjectIdCollection(new[] { reg.ObjectId }));  //Put the Hatch inside the polyline

Any ideas on what might be causing that?

[Kerry]

deckeresq,

Which AutoCAD build ?

Could you post a drawing with just the offending parts ?

Could you post a ZIP of your solution ? ... just to save everyone re-creating your code.

Regards,

[deckeresq]

Kerry,

I'm working with AutoCAD 2014 and the Interop.AutoCAD 1.0.0.0 reference in .Net 4.0.

Here is a drawing:

http://imgur.com/OL0hnWJ

Unfortunately, I can't post a ZIP of the solution due to workplace restrictions (this is for work). I'd be happy to provide any sort of background required, though!

Thanks for looking into this! It's been killing me for weeks.