Issue with calling a .NET LispFunction with a Reactor

Hi All,

I have just hit a wall with some code I am working on and wondered if anyone had seen a similar situation (and found a solution).

I have written a .NET routine that I use to control which Ribbon Menu Tabs and Panels are visible based on arguments passed to the routine. This runs correctly in AutoCAD 2016 when I call it from the command line or from inside a lisp function or command. However when I call the .NET routine from a reactor it fails:

Command: System.ArgumentNullException: Value cannot be null.
Parameter name: key
  at System.Collections.Generic.Dictionary`2.FindEntry(TKey key)
  at System.Collections.Generic.Dictionary`2.TryGetValue(TKey key, TValue& value)
  at Autodesk.AutoCAD.Runtime.PerDocumentCommandClass.Invoke(MethodInfo mi, Boolean bLispFunction)
  at Autodesk.AutoCAD.Runtime.CommandClass.CommandThunk.InvokeLisp(); error: ADS request error

EDIT: I have found that calling ANY command from a reactor fails e.g. (command "line" "0,0" "1000,1000") called by a reactor the error is:

Command: ; error: AutoCAD command rejected: "line"

Any and all thoughts greatly appreciated.

Colin

Yes, you cannot invoke a command from within a reactor callback function - a possible workaround is to invoke the command 'post-process' (using vla-sendcommand, for example).

Thanks to Lee have a look at this for example vla-sendcommand http://www.cadtutor.net/forum/showthread.php?93661-Lisp-for-fillet-radius.

Hi Lee and Al,

Thank you for your replies.

I have added the vla-sendcommand call to my reactor and when I use it to do something "trivial" like zoom extents it works as expected, but when I call the .NET LispFunction it still fails:

(setq activedwg (vla-get-activedocument (vlax-get-acad-object)) )
(vla-SendCommand activedwg "(ribboncontrol \"Sedgman\" \"SedgCAD Legacy\" 0)\r")

Command: (ribboncontrol "Sedgman" "SedgCAD Legacy" 0)
System.ArgumentNullException: Value cannot be null.
Parameter name: key
  at System.Collections.Generic.Dictionary`2.FindEntry(TKey key)
  at System.Collections.Generic.Dictionary`2.TryGetValue(TKey key, TValue& value)
  at Autodesk.AutoCAD.Runtime.PerDocumentCommandClass.Invoke(MethodInfo mi, Boolean bLispFunction)
  at Autodesk.AutoCAD.Runtime.CommandClass.CommandThunk.InvokeLisp(); error: ADS request error
Command:

Note: If I paste (ribboncontrol "Sedgman" "SedgCAD Legacy" 0) directly to the command line it works as expected.

Is there an issue with calling a .NET LispFunction inside a reactor callback function even when using vla-sendcommand?

Maybe I need a completely fresh look at this problem...

What I am attempting to write is contextual ribbon menu control based on a variable set in the current drawing. The .NET Lisp Function I have written shows or hides a ribbon panel based on the arguments passed to it.

On drawing open I set a variable based on the folder the drawing was opened from and display the relevant panels in the ribbon menu. This works on startup, but I was hoping to be able to make the same change (if necessary) when switching drawing tabs (because each drawing can be opened from a different source). I have looked at contextual ribbon tabs in the CUI but that doesn't solve the issue of showing/hiding panels based on a local variable. Using a reactor to call my .NET routine seemed like the correct way to go, but I feel I am pushing the limits of what can be done. Thoughts?

Thanks again,

Colin

EDIT: I am developing this code in AutoCAD 2016 and on a hunch I fired up an AutoCAD 2014 machine and tried to run the code above... it worked perfectly. I was even able to remove the vla-SendCommand and call the .NET LispFunction (with required arguments) directly!!! What has changed in the calling of commands and .NET functions between 2014 and 2016?