Active Contributor
Posts: 28
Registered: ‎07-19-2004
Message 1 of 4 (268 Views)
Accepted Solution

Capturing escape key during a command

268 Views, 3 Replies
12-17-2013 10:33 PM

Hi all,


I have a vb.net Autocad add-in which runs an iterative routine with a while..wend loop that often takes a few minutes to finish.


The routine is very stable and always restores user control eventually, but if the user hits the escape key while it is running, a fatal error occurs in acad.exe.


Does anyone know if there is a way to detect that the escape key has been pressed so the routine is exited?

Posts: 150
Registered: ‎07-20-2011
Message 2 of 4 (256 Views)

Re: Capturing escape key during a command

12-18-2013 12:40 AM in reply to: misterblobby




bool EscapePressed=false;

//before your while loop

Autodesk.AutoCAD.ApplicationServices.Application.PreTranslateMessage += new PreTranslateMessageEventHandler(myEscWatcher);




    //do your work

   if (EscapePressed)





const int KEYDOWN= 0x0100;

void myEscWatcher(object sender, PreTranslateMessageEventArgs messageDetails)
if (messageDetails.Message.message == KEYDOWN && ((Keys)(int)messageDetails.Message.wParam & Keys.KeyCode) == Keys.Escape)
    //do something when ESCAPE has been pressed, for example


ADN Support Specialist
Posts: 311
Registered: ‎04-30-2009
Message 3 of 4 (238 Views)

Re: Capturing escape key during a command

12-18-2013 05:28 AM in reply to: misterblobby



AutoCAD has a property to determine whenever the ESCAPE was pressed, check the posts below:






Augusto Goncalves
Autodesk Developer Network
Active Contributor
Posts: 28
Registered: ‎07-19-2004
Message 4 of 4 (215 Views)

Re: Capturing escape key during a command

12-18-2013 05:25 PM in reply to: augusto.goncalves

Thanks guys,


Easy as that!


Just for convenience, below is the relevant piece of code from the first link above in VB. I had to place it in a few different places to catch the keypress reliably, but it works well if in the right spot.



If HostApplicationServices.Current.UserBreak = True Then
           Throw New Autodesk.AutoCAD.Runtime.Exception(ErrorStatus.UserBreak, "Escape pressed")
            Exit Sub

End If

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