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To add to what Art posted,
You can think of
LayerTable("LayerName") for VB or
LayerTable["LayerName"] for C#
as Indexer Methods which allow access to internal subitems using array-like syntax
Passing in the name of the layer will return its ObjectId so something like this
Dim doc As Document = Application.DocumentManager.MdiActiveDocument
Dim db As Database = doc.Database
Dim ed As Editor = doc.Editor
Dim layerName As String = "LayerName"
Using trx As Transaction = db.TransactionManager.StartTransaction()
Dim bt As BlockTable = trx.GetObject(db.BlockTableId, OpenMode.ForRead)
Dim currentSpace As BlockTableRecord = trx.GetObject(db.CurrentSpaceId, OpenMode.ForRead)
Dim layerTbl As LayerTable = trx.GetObject(db.LayerTableId, OpenMode.ForRead)
If layerTbl.Has(layerName) Then
Dim layerTblRecord As LayerTableRecord = trx.GetObject(layerTbl(layerName), OpenMode.ForWrite)
layerTblRecord.IsLocked = False
End If
trx.Commit()
End Using
Also as Art mentioned one of the overloaded versions of GetObject takes a boolean as a parameter if you want to force objects on Locked layers to be opened.
Hi guys!
Thanks for calling me out on my poor coding abilities! 
I need all the advice I can get as I still have a TON to learn! Most of the code I write is loosley based on an examples I find in books, online or from the forums.
I did not realize that you could force objects on locked layers to be opened, hence the reason I was unlocking the layer first. I have re-written the code to no longer touch the layers. Now I simply unlock the table with an overload of GetObjects.
After running the code again, I am unfortuantely still seeing the same table behaviour. A regen does not bring it back and switching tile mode in my code does not bring it back. The only thing that seems to correct it is closing and reopening the drawing. Am I doing something wrong in the way I am editing the table? If the layer is not locked when the code is run, then the problem does not occur.
Here is my full code:
<CommandMethod("ECDT_NWDataToTable")> _
Public Sub ECDT_NWDataToTable()
'' Declare the current document, database and editor
Dim acDoc As Document = Application.DocumentManager.MdiActiveDocument
Dim acCurDb As Database = acDoc.Database
Dim acEd As Editor = DocumentManager.MdiActiveDocument.Editor
'' Start a transaction
Using acTrans As Transaction = acCurDb.TransactionManager.StartTransaction()
Try
Dim acBt As BlockTable = acDoc.Database.BlockTableId.GetObject(OpenMode.ForRead)
Dim acBtrMs As BlockTableRecord = DirectCast(acBt(BlockTableRecord.ModelSpace).GetObject(OpenMode.ForRead), BlockTableRecord)
Dim myLeadVals As New List(Of String)
Dim myLeadQtys As New List(Of String)
Dim Splits As String() = Nothing
'' Get embed (BOM) multileader contents
For Each objId As ObjectId In acBtrMs
Dim acMlead As MLeader = TryCast(acTrans.GetObject(objId, OpenMode.ForRead), MLeader)
If acMlead IsNot Nothing Then
Dim MleadStyle As MLeaderStyle = acTrans.GetObject(acMlead.MLeaderStyle, OpenMode.ForRead)
Dim strMlStyle As String = MleadStyle.Name
If strMlStyle = "ECDT_ANO_NW-BoM" Then
Dim strMtextValue As String
strMtextValue = acMlead.MText.Text
Splits = strMtextValue.Split(New [Char]() {"'"c, "-"c, ChrW(39), ChrW(34), ChrW(13)}, StringSplitOptions.RemoveEmptyEntries)
myLeadQtys.Add(Splits(0))
myLeadVals.Add(Splits(1))
If myLeadQtys.Count > 21 Then
MsgBox("Too many BoM tags for data table! Remove tag(s) and try again.", , "Data Error")
Exit Sub
End If
End If
End If
Next
'' Open table and add multileader values to table
Dim acBtrPs As BlockTableRecord = DirectCast(acBt(BlockTableRecord.PaperSpace).GetObject(OpenMode.ForRead), BlockTableRecord)
For Each objId As ObjectId In acBtrPs
Dim acTable As Table = TryCast(acTrans.GetObject(objId, OpenMode.ForWrite, False, True), Table)
If acTable IsNot Nothing Then
Dim strTblStylName As String = acTable.TableStyleName
If strTblStylName = "ECDT_NW-BillofMaterials" Then
Dim range As CellRange = CellRange.Create(acTable, 2, 0, 22, 1)
range.DeleteContent()
Dim iCnt As Integer = myLeadQtys.Count + 2
Dim j As Integer = 0
For i As Integer = 2 To iCnt - 1
acTable.Cells(i, 0).TextString = myLeadQtys(j)
acTable.Cells(i, 1).TextString = myLeadVals(j)
j = j + 1
Next
acTable.DowngradeOpen()
End If
End If
Next
acCurDb.TileMode = Not acCurDb.TileMode
acCurDb.TileMode = Not acCurDb.TileMode
Catch ex As Autodesk.AutoCAD.Runtime.Exception
MsgBox("An error has occured. Please contact you system administrator." & vbCr & vbCr & ex.Message & vbCr & ex.StackTrace)
Finally
End Try
acTrans.Commit()
End Using
End Sub
I am also attaching a sample drawing where the issue occurs.
Thanks for your help!
I ran your code and dwg in AutoCAD 2012 and I see what you mean. When the layer is locked the table cell borders go weird!!
I tried a number of different techniques to try to regenerate the table but none seemed to work. I tried to unlock the layer within the command, change the table, and then re-lock the layer. Still to no avail.
Welcome to strange happenings in the world of the AutoCAD API 
Below is my suggested workaround. Although not ideal, it does work!
The approach here is to create seperate commands to do the following:
1. Unlock the layer if it is locked.
2. Update the table.
3. Re-lock the layer if it was originally locked.
4. Create a command to send the commands in 1-3 to the command-line.
An outline of these commands would be as follows:
'***********************************************************************************************************
Public Class CommandClass
'Class level variable
Dim isLayerLocked As Boolean = False
<CommandMethod("UnlockLayer", CommandFlags.NoUndoMarker)>
Public Sub UnlockLayer()
'If layer is locked, set isLayerLocked variable to True and unlock the layer.
End Sub
<CommandMethod("UpdateTable", CommandFlags.NoUndoMarker)>
Public Sub UpdateTable ()
‘Update table.
End Sub
<CommandMethod("ReLockLayer", CommandFlags.NoUndoMarker)>
Public Sub ReLockLayer ()
‘Check isLayerLocked variable, and if True then re-lock the layer.
End Sub
<CommandMethod("ECDT_NWDataToTable")>
Public Sub ECDT_NWDataToTable()
Dim doc As Document = Application.DocumentManager.MdiActiveDocument
‘Send commands to command-line.
doc.SendStringToExecute("UnlockLayer UpdateTable LockLayer ", False, False, False)
End Sub
End Class
'***********************************************************************************************************
Notes:
1. The UnlockLayer, UpdateTable and ReLockLayer commands have the CommandFlags.NoUndoMarker in command attribute.
I've done this so that if the user wants to UNDO the ECDT_NWDataToTable command, they won't have to perform repeated
undos for each of the sub-commands.
2. The echoCommand parameter in the SendStringToExecute() method is set to False, so that the user will only see
ECDT_NWDataToTable in the command-line.
Hope this helps.
Art
Hey Art! This is great stuff! Works great!
Too bad about the table not updating properly. Seems to be a bug of sorts? Do you know if there is a procedure that differs from the regular method for AutoCAD bug reporting (Product Feedback Form) to get this info to Autodesk so they can look into it?
Thanks for all of your help! I will accept your post as the solution, but if you (or anyone else) discover how to get the table to update properly, please let me know!
Thanks again!
