Merging sheets creates conflict when images exists on both sheets

Question

Hi
I have a solution of creating and merging Excel-files in a webservice.
This has been working fine, until both of the Excel-files began to contain images.
As an example, the service recieves one Excel template and one Excel workbook.
The goal is to create a new Excel workbook consisting of the supplied parts.
Since the template is indeed a template (xltx), I start of by working with the workbook.
I then merge all worksheets from the template file to the workbook file.
This is done in memory with the help of
EPPlus version 3.1.2 and the following routine where grmName is path to the template file and wbkName is path to the workbook:
Friend Sub XLAddInfoSheets(ByVal grmName As String, ByVal wbkName As String)
Dim targetFI As New FileInfo(wbkName)
Dim templateFile As String = grmName
Dim ContentOverrides As New ArrayList
Try
Using t As New ExcelPackage
Using Tstream As New FileStream(wbkName, FileMode.Open, FileAccess.ReadWrite)
t.Load(Tstream)
End Using
Using d As New ExcelPackage
Using Dstream As New FileStream(templateFile, FileMode.Open)
d.Load(Dstream)
End Using
For Each dws In d.Workbook.Worksheets
Dim addOK As Boolean = True
If dws.Name = "Försättsblad" Or dws.Name = "Cover Page" Then
Dim tmpName As String = dws.Name
For Each twx In t.Workbook.Worksheets
If LCase(twx.Name) = LCase(tmpName) Then
addOK = False
Exit For
End If
Next
If addOK Then
t.Workbook.Worksheets.Add(tmpName, dws)
t.Workbook.Worksheets(tmpName).Hidden = dws.Hidden
End If
End If
Next
End Using
t.SaveAs(targetFI)
End Using
Catch ex As Exception
WriteLogg("Could not merge coverpages from the template.", ex.Message, logFile)
Exit Sub
End Try
End Sub
When opening the created file (if both the template and the workbook contains images) shows a repairable error.
After the repair is made, the images in the inserted sheets is actually an image from the original workbook, not the same image as in the template sheet.
I realise that there is a mixup of relations causing this, so I tried looping through the images in the inserted sheets and delete the original image (DrawingPart) and add the image again.
This is done with the following code where wbPart is the actual Workbookpart and imagePath is path to the image which is extracted to disk earlier:
Private Sub XLRelateImages(ByVal wbPart As WorksheetPart, ByVal imagePath As String)
Try
Dim drawingPart = wbPart.DrawingsPart
If drawingPart IsNot Nothing Then
Dim doc As New XmlDocument()
doc.Load(drawingPart.GetStream())
Dim ns As New XmlNamespaceManager(doc.NameTable)
ns.AddNamespace("a", "http://schemas.openxmlformats.org/drawingml/2006/main")
ns.AddNamespace("xdr", "http://schemas.openxmlformats.org/drawingml/2006/spreadsheetDrawing")
Dim list As XmlNodeList = doc.SelectNodes("/xdr:wsDr/xdr:twoCellAnchor/xdr:pic/xdr:blipFill/a:blip", ns)
Dim pairList As New List(Of KeyValuePair(Of String, String))()
For Each node As XmlNode In list
For Each attribute As XmlAttribute In node.Attributes
Dim pair As New KeyValuePair(Of String, String)(attribute.Value, attribute.Name)
pairList.Add(pair)
Next
Next
For Each image As KeyValuePair(Of String, String) In pairList
Dim id As String = image.Key
Dim name As String = image.Value
Dim oldPart As OpenXmlPart = Nothing
If name = "r:embed" Then
' get ImagePart via id
oldPart = drawingPart.GetPartById(id)
' delete ImagePart
drawingPart.DeletePart(oldPart)
' add the ImagePart
Dim newPart As ImagePart = drawingPart.AddImagePart(ImagePartType.Png, id)
' replace image
Dim replacement As String = imagePath
Using stream As New FileStream(replacement, FileMode.Open)
' feed data to the newPart
newPart.FeedData(stream)
End Using
End If
Next
' save xml document to the stream
doc.Save(drawingPart.GetStream(FileMode.Create))
End If
Catch ex As Exception
End Try
End Sub
When I examine the result of this I still get the same error when I'm opening the file, but the correct image is now shown on the inserted sheets.
I believe there must be some other relation that is left in the workbook, but I have not been able to locate it.
Can someone help with sample code in VB or C# I would be much obliged?
Best Regards Peter Karlström Midrange AB, Sweden

Answer 1

This is the code I finally ended up with.
It's all working now, but the code is a bit locked in to this solution, since it only handles 1 custom sheet property.
Private Sub XLCheckSheetProperties(ByVal wBook As String)
Using sDocument As SpreadsheetDocument = SpreadsheetDocument.Open(wBook, True)
Dim workbookPart As WorkbookPart = sDocument.WorkbookPart
workbookPart.Workbook.Descendants(Of Sheet)()
Dim worksheetPart As WorksheetPart = workbookPart.WorksheetParts.Last
For Each Sheet As Sheet In sDocument.WorkbookPart.Workbook.Sheets
Dim sName As String = Sheet.Name
Select Case sName
Case "Cover Page"
If Not XLSheetPropertyRemove(sDocument, sName) Then
WriteLogg("Kunde inte ta bort metadata i försättsbladet " & sName & ".", "XLCheckSheetProperties", logFile)
End If
If Not XLSheetPropertyAdd(sDocument, sName, "sht_Footerdata", "0:0") Then
WriteLogg("Kunde inte lägga till metadata i försättsbladet " & sName & ".", "XLCheckSheetProperties", logFile)
End If
End Select
Next
End Using
End Sub
Private Function XLSheetPropertyRemove(ByVal document As SpreadsheetDocument, ByVal sheetName As String) As Boolean
XLSheetPropertyRemove = False
Try
Dim sheet1 As Sheet = document.WorkbookPart.Workbook.Descendants(Of Sheet)().[Single](Function(s) s.Name = sheetName)
Dim workSheet1 As Worksheet = DirectCast(document.WorkbookPart.GetPartById(sheet1.Id), WorksheetPart).Worksheet
For Each cusProps As CustomProperties In workSheet1.Elements(Of CustomProperties)()
cusProps.Remove()
Next
XLSheetPropertyRemove = True
Catch ex As Exception
End Try
End Function
Private Function XLSheetPropertyAdd(ByRef document As SpreadsheetDocument, ByVal sheetName As String, ByVal propName As String, ByVal propValue As String) As Boolean
XLSheetPropertyAdd = False
Try
Dim workbookPart As WorkbookPart = document.WorkbookPart
Dim sheet1 As Sheet = document.WorkbookPart.Workbook.Descendants(Of Sheet)().[Single](Function(s) s.Name = sheetName)
Dim workSheet1 As Worksheet = DirectCast(document.WorkbookPart.GetPartById(sheet1.Id), WorksheetPart).Worksheet
Dim relId As String = workbookPart.Workbook.Descendants(Of Sheet)().First(Function(s) sheetName.Equals(s.Name)).Id
Dim wsPart As WorksheetPart = document.WorkbookPart.GetPartById(relId)
Dim customPropertyPart As CustomPropertyPart = wsPart.AddCustomPropertyPart(CustomPropertyPartType.Spreadsheet, "rIdProp2")
Dim byteArray As Byte() = System.Text.Encoding.Unicode.GetBytes(propValue)
Dim stream As New MemoryStream(byteArray)
Dim data As System.IO.Stream = stream
customPropertyPart.FeedData(data)
data.Close()
Dim customProperties As CustomProperties = workSheet1.AppendChild(Of CustomProperties)(New CustomProperties())
Dim customProperty As CustomProperty = customProperties.AppendChild(Of CustomProperty)(New CustomProperty())
customProperty.Id = "rIdProp2"
customProperty.Name = propName
XLSheetPropertyAdd = True
Catch ex As Exception
End Try
End Function
The trick was to delete the custom sheet property and the recreate it.
Best Regards Peter Karlström Midrange AB, Sweden