Catia VBA - Automation Error Get Object - excel

Question

I am getting an Automation error, when Catia is trying to write values in a selected Excel sheet. It's a bit confusing because on the first try of the code there was no error and the values were in the Excel sheet.
I didn't change the code, but on the second try I get:
Run-time error '-2147417846 (8001010a)': Automation error
"The Message filter indicated that the application is busy."
on the line: Set MyXL = GetObject(FPath)
Sub CATMain()
FPath = CATIA.FileSelectionBox("Select the Excel file you wish to put the value in", "*.xlsx", CatFileSelectionModeOpen)
If FPath = "" Then
Exit Sub
End If
Set xlApp = CreateObject("Excel.Application")
Set MyXL = GetObject(, "Excel.Application")
Set MyXL = GetObject(FPath)
MyXL.Application.Visible = True
MyXL.Parent.Windows(1).Visible = True
Dim oSelection As Selection
Set oSelection = CATIA.ActiveDocument.Selection
Dim oProduct As AnyObject
On Error Resume Next
Set oProduct = oSelection.FindObject("CATIAProduct")
If (Err.Number <> 0) Then
MsgBox "No selected product"
Else
On Error GoTo 0
Dim oInertia As AnyObject
Set oInertia = oProduct.GetTechnologicalObject("Inertia")
Dim dMass As Double
dMass = oInertia.Mass
Dim dDen As Double
dDen = oInertia.Density
MsgBox oProduct.Name & ": Masse = " & CStr(dMass) & " KG" & ": Dichte = " & (CStr(dDen) / 1000) & " "
MyXL.Application.Cells(1, 1).Value = "Masse"
MyXL.Application.Cells(2, 1).Value = dMass
MyXL.Application.Cells(1, 2).Value = "Dichte"
MyXL.Application.Cells(2, 2).Value = "dDen"
MsgBox "Werte wurden in Excel eingetragen"
End If
End Sub

Answer 1

It appears you did not set Option Explicit - put it on the first line and it will help you avoid errors. (With it, the compiler will force you to declare all your variables. This will also mean that when you put it in, your code will not work unless you declare all variables.)
The first problem:
Set xlApp = CreateObject("Excel.Application")
Set MyXL = GetObject(, "Excel.Application")
You first create a new instance of Excel with CreateObject and store a reference to it in xlApp (which you subsequently do not use). Then you try to get a reference to an existing Excel instance with GetObject and store its reference in MyXL. This only works reliably because you first create a new instance. Otherwise you could not guarantee that there always is an Excel instance available.
A related problem is, that you don't release/close these instances. If you create an Excel instance, you need to close it with xlApp.Quit after you're done using it, otherwise it will linger around.
Be careful though with instances you took over with GetObject - calling MyXL.Quit will close the instance regardless of what other workbooks are open at that time.
Similarly, if you open a file this way, you need to make sure to close it afterwards. Otherwise you'll run into the problem you experience: Write protected files.
So, to mend your problem: Close all open instances of Excel (best done via Task Manager, as some of them might be invisible). Then adjust your code to only use one reference to an Excel.Application. And finally make sure to .Close the workbook after you've saved it and .Quit your Excel instance. This should hopefully prevent the error from reappearing.
'Dim xlApp As Excel.Application ' early-bound declaration
'Set xlApp = New Excel.Application ' early-bound assignment
Dim xlApp As Object ' late-bound declaration
Set xlApp = CreateObject("Excel.Application") ' late-bound assignment
'Dim wb As Workbook ' early-bound declaration
Dim wb as Object
Set wb = xlApp.Workbooks.Open(FPath)
' stuff you want to do with the workbook
wb.Close SaveChanges:=True
xlApp.Quit
If you can add a reference to the Excel object model in you Catia VBA project (not sure about that), you can comment out the late-bound lines and use the early-bound lines instead. That way you gain the very useful IntelliSense for the Excel objects. Which makes it so much easier to code.

Answer 2

Thank you guys! I've solved the Problem with simply adding the code:
Workbook.Close SaveChanges:=True