Modify Color Fill Value fails

[Hakan]

Can anyone explain why the following code runs with no errors, the debug shows correct DeviceGray values, consistent with the content of the PDF, but yet the OUTPUT has no change.

My goal is to change "fill" values of content objects.

thank you

    Dim outputfile As String = "C:\output.pdf"
    Dim file As New File("C:\inputfile.pdf")
    Dim document As Document = file.Document

    For Each page As Page In document.Pages
        Dim contents As Contents = page.Contents

        For Each obj As ContentObject In contents
            AdjustFillValue(obj)
        Next

        contents.Flush()

    Next

    Serialize(file, outputfile)

end

Private Sub AdjustFillValue(content As ContentObject)

    If TypeOf content Is ContainerObject Then
        For Each obj As ContentObject In DirectCast(content, ContainerObject).Objects
            AdjustFillValue(obj)
        Next

    ElseIf TypeOf content Is SetDeviceCMYKFillColor Then
        '... to implement

    ElseIf TypeOf content Is SetDeviceGrayFillColor Then

        Dim FillColor As SetDeviceGrayFillColor = DirectCast(content, SetDeviceGrayFillColor)
        Debug.WriteLine("GrayFill=" & FillColor.ToString()) 'VALUES RETURN OK (0 to 1 range) 
        'DEBUG PROVES INPUT PDF HAS DEVICEGRAY COLOR CONTENT
        FillColor = New SetDeviceGrayFillColor(New colorSpaces.DeviceGrayColor(0.1)) 'NO IMPACT ON OUTPUT
        content = New SetDeviceGrayFillColor(New colorSpaces.DeviceGrayColor(0.1)) 'NO IMPACT ON OUTPUT
    *How can I set new fillcolor ?*

    ElseIf TypeOf content Is SetDeviceRGBFillColor Then
        'to implement

    ElseIf TypeOf content Is SetFillColor Then
        'to implement

    End If

End Sub

[Hakan]

never mind, I figured this one out myself
assigning the fill object to a new objects breaks it
FillColor.Components(0) = .... works fine