topic Re: Documents.Open fails, while ActiveDocument succeeds in .NET Forum

Documents.Open fails, while ActiveDocument succeeds

oransen — Mon, 09 Nov 2020 11:13:27 GMT

I'm at a loss as to why this is, here is the code, I've missed something important I imagine:

{ // Open AutoCAD and get it as a variable in C#... AcadApplication AcadApp; AcadApp = new AcadApplication(); // Make sure the AutoCAD windows are visible // (But note that making it invisible probably speeds up processing.) AcadApp.Application.Visible = true; AcadDocument AcadDoc; #if false // Get the active document, which in this case is the default empty document which // This uses the default document AutoCAD starts with, and works AcadDoc = AcadApp.ActiveDocument; #else // This opens a document, but any attempt to use it fails AcadDoc = AcadApp.Documents.Open(@"D:\Temp\CSHARP.DWG"); #endif AcadDoc.Layers.Add("TestLayer"); // Model space is actually where most of the entities (LINE,CIRCLE,POINT etc) in an AutoCAD DWG file live. var ModelSpace = AcadDoc.ModelSpace; }

See the stuff around "#if false"

The crash occurs at Add ("TestLayer") as if AcadDoc is not valid.

The error message is (translated from Italian) the "called has rejected the caller's function call"

Re: Documents.Open fails, while ActiveDocument succeeds

oransen — Wed, 11 Nov 2020 10:38:50 GMT

It looks like

AcadDoc = AcadApp.Documents.Open(@"D:\Temp\CSHARP.DWG");

does not on its own create a valid AcadDocument. I've found that if I do some "dummy" work before using the AcadDoc then all works fine:

AcadDocument AcadDoc = AcadApp.Documents.Add(); AcadDoc.Activate(); AcadDoc.Close(false); // With the above three "dummy" lines above the Open works fine... AcadDoc = AcadApp.Documents.Open(@"C:\DisegniSviluppati\04.DWG");

I still think I am missing something...

Re: Documents.Open fails, while ActiveDocument succeeds

kean_walmsley — Wed, 11 Nov 2020 12:17:22 GMT

Hi Owen,

Hopefully this will help:

https://www.keanw.com/2010/02/handling-com-calls-rejected-by-autocad-from-an-external-net-application.html

Best,

Kean

Re: Documents.Open fails, while ActiveDocument succeeds

oransen — Wed, 11 Nov 2020 14:12:28 GMT

Thanks for the pointers. I'd seen you article, but hand not understood it was relevant. I still don't understand all the COM/NET stuff, but from the article you are saying that AutoCAD may not be ready when I make my call to, in this case Open, and I should try again "later".

I was hoping that I could simply do...

#using AutoCAD ;

...and call the various functions.

With your article I've modified the Open code like this:

AcadDocument AcadDoc = null; int iNumTries = 0; const int ikMaxTries = 400; while (iNumTries < ikMaxTries) { bool bError = false ; try { AcadDoc = AcadApp.Documents.Open(@"C:\DisegniSviluppati\04.DWG"); AcadDoc.Activate(); } catch (Exception e1) { Debug.WriteLine("Catch on try " + iNumTries.ToString() + ", exception: " + e1.Message + "\n"); bError = true; } if (!bError) { break; } if (iNumTries == ikMaxTries) { break; } iNumTries++; } if (iNumTries == ikMaxTries) { return; }

...and it works. But it seems a lot of work just to open a drawing file.

Does the "rejected calls problem" mean I have to have a lot of wrappers and/or deeply understand the article you posted? Or is it just a problem with Open()?

Re: Documents.Open fails, while ActiveDocument succeeds

kean_walmsley — Wed, 11 Nov 2020 16:00:36 GMT

Hi Owen,

This post (and my knowledge of the subject) is now over a decade old, so I'm afraid I'm going to be of limited help.

Hopefully someone who has hit this issue more recently can chime in.

Best,

Kean

Re: Documents.Open fails, while ActiveDocument succeeds

oransen — Wed, 11 Nov 2020 17:04:11 GMT

Thanks for all your help, I'd never have got this far without it.

It looks like this method of accessing AutoCAD with C# is never really used. There's lots of short examples, and that's that.

I'll go back to using C# as a DLL plugin, much safer!

Re: Documents.Open fails, while ActiveDocument succeeds

_gile — Wed, 11 Nov 2020 18:37:04 GMT

Hi,

@oransen a écrit :

I'll go back to using C# as a DLL plugin, much safer!

I totally agree with this, anyway, here's a way with the COM API from a standalone application.

// get or create AutoCAD.Application AcadApplication acApp = null; const string strProgId = "AutoCAD.Application"; try { acApp = (AcadApplication)Marshal.GetActiveObject(strProgId); } catch { try { acApp = (AcadApplication)Activator.CreateInstance(Type.GetTypeFromProgID(strProgId), true); } catch { MessageBox.Show("Cannot create an instance of 'AutoCAD.Application'."); return; } } try { //wait for AutoCAD is visible while (true) { try { acApp.Visible = true; break; } catch { } } acApp.Documents.Open(@"D:\Temp\CSHARP.DWG", true); var acadDoc = acApp.ActiveDocument; // do your stuff with acadDoc here } catch (System.Exception ex) { MessageBox.Show("Error: " + ex.Message); }

Re: Documents.Open fails, while ActiveDocument succeeds

oransen — Wed, 11 Nov 2020 19:18:31 GMT

Thanks for that, but it looks a bit tricky, and if I have to do it for other commands...

Or are you saying it will only happen with the initial Open...?