I have a VB.NET program which is very similar to another which functions fine. In the troubled program when I enable a Try Catch block right after starting a transaction it invariably throws a Unhandeled Access Violation right at the transaction phrase. If I remove the Try/Catch and replace it with an OnError Resume Next it completes execution but does not do what it is supposed to (extract four drawing border attribute values)
I have checked the sequence against the program which functions and other than the troubled program being in ACAD2012 and VS 2010 they are pretty much identical (Resources, database access etc... )
Any help or suggestions appreciated.
CODE FOLLOWS:
Note: DB established as: Dim db As Autodesk.AutoCAD.DatabaseServices.Database = SelectDatabase(f, False)
(and then through selectdatabase): db.ReadDwgFile(fullname,FileOpenMode.OpenForReadAndAllShare, True, Nothing)
' Used in LoadAttributesFromDrawingIntoXML
Function GetAttributes(ByVal db AsDatabase, ByVal filepath AsString) AsCollection
Dim collection AsNewCollection
Dim flag AsBoolean = False'
Dim tr AsTransaction= db.TransactionManager.StartTransaction
Try ' - I enable the try and I get an unhandeled access violation. . .
Dim id AsObjectId, bt AsBlockTable = tr.GetObject(db.BlockTableId, OpenMode.ForRead)
ForEach btrID AsObjectIdInbt
Dim btr AsBlockTableRecord = tr.GetObject(btrID, OpenMode.ForRead)
acadEd.WriteMessage(" Btr name: "& btr.Name.ToString)
If btr.IsLayout Then
Dim l AsLayout = tr.GetObject(btr.LayoutId, OpenMode.ForRead)
Dim LayoutArr AsLayoutInfo = NothingForEach id Inbtr
Dim entity AsEntity = TryCast(tr.GetObject(id, OpenMode.ForRead), Entity)
If (Not entity IsNothing) Then If TypeOf entity IsBlockReferenceThen
Dim br AsBlockReference = TryCast(entity, BlockReference)
Dim borderNames = (From all In GetXelementFromCollection("BORDERINFO").Elements
Select all.<NAME>.Value.ToUpper).Distinct
If (From all In GetXelementFromCollection("BORDERINFO").Elements Where
all.<NAME>.Value.ToUpper = br.Name.ToUpper Select all).Count > 0 Then
Dim attributeCollection As _
Autodesk.AutoCAD.DatabaseServices.AttributeCollection=
br.AttributeCollection
Dim IsValid AsBoolean = False
Dim UniqueBlockName AsString = ""Dim BlkArr AsNewBlockInfo(br.Name,
IsValid, UniqueBlockName, br.Handle.Value)
ForEach atID AsObjectIdInattributeCollection
Dim atRef AsAttributeReference = atID.GetObject(OpenMode.ForRead)
Dim atInfo AsNewAttributeInfo
WithatInfo
._Tag = atRef.Tag
._Text = atRef.TextString
._ObjectID = atRef.ObjectId.OldIdPtr.ToInt64
._BlockName = br.Name
._HandleValue = atRef.ObjectId.Handle.Value
EndWith
BlkArr.Add(atInfo)
Next
If LayoutArr IsNothingThen
LayoutArr = NewLayoutInfo(l.LayoutName)
LayoutArr.Add(BlkArr)
Else
LayoutArr.Add(BlkArr)
EndIf
EndIf
EndIf
EndIf
Next 'id'--add layout collections
If Not LayoutArr IsNothingThen collection.Add(LayoutArr)
EndIf'islayout
Next'btr
Catch ex As System.Exception
tr.Abort()
System.Windows.Forms.
MessageBox.Show("Error in (GetAttributes)") ' & vbCr & ex.Message, "Error occured")
db.Dispose()
Finally
tr.Dispose()
db.Dispose()
EndTry
Return collection
EndFunction
