Preserving ActiveSheet.RowFilter

Preserving ActiveSheet.RowFilter

Posted by: scottp on 25 June 2023, 5:20 pm EST

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  scottp

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  Posted 25 June 2023, 5:20 pm EST

  Hi,

  I have a situation where a user may apply row filtering to the grid. Programmatically, I want to be able to save any currently applied row filtering, clear the row filter, refresh the data, and then re-apply the preserved row filter.

  I am saving away the current row filter information like this:

  Dim myMemoryStream As New MemoryStream
  Dim myXmlTextWriter As New System.Xml.XmlTextWriter(myMemoryStream, System.Text.Encoding.UTF8)
  myXmlTextWriter.Formatting = Formatting.Indented
  myXmlTextWriter.Indentation = 2
  myXmlTextWriter.WriteStartDocument()
  myXmlTextWriter.WriteStartElement("AppliedFilter")
  activeSheet.RowFilter.Serialize(myXmlTextWriter)
  myXmlTextWriter.WriteEndElement()
  myXmlTextWriter.WriteEndDocument()
  myXmlTextWriter.Flush()
  If myMemoryStream.Position > 0 Then
  	myMemoryStream.Position = 0
  End If
  filterXmlDocument = New XmlDocument()
  filterXmlDocument.Load(myMemoryStream)
  myXmlTextWriter.Close()

  I am clearing the row filter like this:

  activeSheet.ClearRowFilter()

  I then set activeSheet.Rows.Count to 0, and repopulate the grid with saved data.

  Now I need to re-apply the saved RowFilter information. I am trying this:

  If filterXmlDocument IsNot Nothing Then
  	Dim node As System.Xml.XmlNode
  	node = filterXmlDocument.FirstChild
  	While Not node.Name.Equals("AppliedFilter")
  		node = node.NextSibling
  	End While
  	Dim myXMLNodeReader As New System.Xml.XmlNodeReader(node)
  	myXMLNodeReader.Read()
  	activeSheet.RowFilter.Deserialize(myXMLNodeReader)
  End If

  …but get an error of “System.NullReferenceException: ‘Object reference not set to an instance of an object.’ FarPoint.Win.Spread.SheetView.RowFilter.get returned Nothing.” at the “activeSheet.RowFilter.Deserialize(myXMLNodeReader)” line.

  Please advise. Should I even be using the Serialize() and Deserialize() methods for preserving and re-applying a row filter?

• 

  aastha.gupta

  

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  Posted 27 June 2023, 4:29 am EST

  Hi Scott,

  The error has occurred because SheetView’s ClearRowFilter() method set its RowFilter property to null and hence you got the error at “activeSheet.RowFilter.Deserialize(myXMLNodeReader)” line.

  We suggest you modify the code to apply saved filters as follows:

    fpSpread1.ActiveSheet.Columns(0, 5).AllowAutoFilter = True 'Filter property as set earlier
      fpSpread1.ActiveSheet.AutoFilterMode = FarPoint.Win.Spread.AutoFilterMode.EnhancedContextMenu  'The filter you set to your data previously
      If _filterXmlDocument IsNot Nothing Then
          Dim node = _filterXmlDocument.FirstChild
          While node IsNot Nothing AndAlso Not node.Name.Equals("AppliedFilter")
              node = node.NextSibling
          End While
          If node IsNot Nothing Then
              Dim myXMLNodeReader As XmlNodeReader = New XmlNodeReader(node)
              myXMLNodeReader.Read()
              fpSpread1.ActiveSheet.RowFilter.Deserialize(myXMLNodeReader)
          End If
      End If

  We have attached a sample application for your reference. Please check SaveRowFilter_VB.zip

  In case your requirement differs from our understanding, we request you provide us more information about how you repopulate the data as you have stated in the following line:

  “I then set activeSheet.Rows.Count to 0, and repopulate the grid with saved data.”

  It would be helpful if you could provide us with a stripped-down version of the sample application that shows the issue on your end. Alternatively you can update the attached sample so that we can replicate the issue on our end for further analysis.

  Thanks & Regards,
  
  Aastha

• 

  scottp

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  Posted 27 June 2023, 1:03 pm EST

  That’s fixed it. Thanks!