Layout eNullObjectID

[bherber]

I have a very wierd issue that i have been battling with.

I currently had a C# method that i was using for Plotting.  the method works fine when i call it from a CommandMethod (off of the base class)but when i try calling it from a usercontrol i get an exception of NullObjectID. it crashes on

"Layout layout = Tx.GetObject(layoutMgr.GetLayoutId(layoutMgr.CurrentLayout), OpenMode.ForWrite) as Layout;"

i have used user contols and PalleteSets and they both crash out.  HELP

public void SimplePlot(string Pc3PrinterName)
{
Document doc = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager.MdiActiveDocument;
Editor ed = doc.Editor;
Database db = doc.Database;

using (Transaction Tx = doc.Database.TransactionManager.StartTransaction())
{
PlotSettingsValidator psvc = PlotSettingsValidator.Current;
LayoutManager layoutMgr = LayoutManager.Current;
Layout layout = Tx.GetObject(layoutMgr.GetLayoutId(layoutMgr.CurrentLayout), OpenMode.ForWrite) as Layout;
psvc.RefreshLists(layout);
Tx.Commit();
}

...

}

[norman.yuan · Accepted solution]

Based your description of the problem, it is very likely that you need to lock the document before accessing drawing database/starting transaction, that is, wrap up the operation in 

using (var lk=doc.LockDocument())

{

  //Do your work here

}