Community
From your Jig class, it is hard to tell what the purpose of the jig. if you are to draw a polyline from nothing, using EntityJig might be better option. DrawJig is usually used for presenting a visual clue of how an existing entity would be transformed. But for your case, I guess you use Jig to get the start point and a rotation angle for a fixed sized polyline to be drawn.
From your code I can see 2 issues:
1. The code crash when user select keywork "R", while moving cursor is OK. You may want to try a loop to enclose the prompts.AcquirePoint(), so that user enters keywork, the code set variable "angle" and loop back to prompts.AcquirePoint(). It only breaks out the loop the PromptResult is OK or Cancel. Something like:
Protected Overrides Function Sampler(ByVal prompts As Autodesk.AutoCAD.EditorInput.JigPrompts) As Autodesk.AutoCAD.EditorInput.SamplerStatus
Do
Dim po As New JigPromptPointOptions(vbLf & "Position of slab")
po.SetMessageAndKeywords(vbLf & "Specify position of slab or " & "[Rotate]", "R")
myPR = prompts.AcquirePoint(po)
If myPR.Status = PromptStatus.Keyword Then
Select Case myPR.StringResult
Case "R"
angle = angle + 90 * Math.PI / 180
'Program crash here
Exit Select
End Select
''Remove this
''Return SamplerStatus.OK
ElseIf myPR.Status = PromptStatus.OK Then
If myPR.Value.IsEqualTo(BasePt) Then
Return SamplerStatus.NoChange
End If
BasePt = myPR.Value
Return SamplerStatus.OK
End If
Loop While (True)
Return SamplerStatus.Cancel
End Function
I guess the crash has something to do with the fact that in your code, if user enter keywork R, the sSampler()method still returns samplerStatus.OK, which triggers WorldDraw(), but somehow, the BasePt is unchanged, thus some calculation in the WorldDraw() cannot go ahead (I did not looked into, though).
2. The biggest issue I can see is taht in the WorldDraw() method, your code actaully create many (or too many) polyline objects without dispose them. With minor move of the mouse, the WorldDraw(0 is triggered, and a polyline object is created, and only used for rendering a visual image and yoru code leave it behind. If user drag the Jig for a few seconds, there could be hundreds of thousands of polyline being created in the memory.
You shold create a polyline at class level, and only update/transform it in WordDraw() for the changed location/angle. And at the end of the Jig, you either add this Polylne into database (that is why I suggest to use EntityJig), or retrieve the points/angle to update existing polylne and dispose the polyline iin the Jig class (you may implement IDisposable interface).
You are new-ing a Polyline in your worldDraw, this is what you need to dispose. Basically you need to dispose any AutoCAD entity that is NOT added to the database, because AutoCAD won't do it for you. The worldDraw callback is invoked quite often during the jig, which will lead to non neglectible leak in your code.
An easy way to do it is to use the "using" keyword along the Polyline you are creating.
There are many examples of Jigs on our blogs, please take a look if you are not familiar with it:
http://adndevblog.typepad.com/autocad/2012/10/autocadnet-lesson-7-jig.html
Regards,
Philippe.
Philippe Leefsma
Developer Technical Services
Autodesk Developer Network
