Public Sub XLDeleteCommentsByUser(ByVal fileName As String, ByVal userName As String)
   Const commentsSchema As String = "http://schemas.openxmlformats.org/spreadsheetml/2006/main"
   Dim doc As SpreadsheetDocument = SpreadsheetDocument.Open(fileName, True)
   '  Manage namespaces to perform XML XPath queries.
   Dim nt As NameTable = New NameTable
   Dim nsManager As XmlNamespaceManager = New XmlNamespaceManager(nt)
   nsManager.AddNamespace("sh", commentsSchema)
   For Each part As WorksheetPart In doc.WorkbookPart.WorksheetParts
      If (Not (part.WorksheetCommentsPart) Is Nothing) Then
         Dim commentDoc As XmlDocument = New XmlDocument
         commentDoc.Load(part.WorksheetCommentsPart.GetStream)
         Dim searchString As String = String.Format("//sh:authors/sh:author[text()='{0}']", userName)
         Dim node As XmlNode = commentDoc.SelectSingleNode(searchString, nsManager)
         If (Not (node) Is Nothing) Then
            Dim nodes As XmlNodeList = node.SelectNodes("preceding-sibling::sh:author", nsManager)
            Dim authorID As Integer = nodes.Count

            Dim commentListNode As XmlNode = commentDoc.SelectSingleNode("sh:comments/sh:commentList", nsManager)
            If (Not (commentListNode) Is Nothing) Then
               searchString = String.Format("./sh:comment[@authorId='{0}']", authorID)
               Dim comments As XmlNodeList = commentListNode.SelectNodes(searchString, nsManager)
               For Each commentNode As System.Xml.XmlNode In comments
                  commentListNode.RemoveChild(commentNode)
               Next
            End If
         End If
         '  Save the comment XML back to its part.
         commentDoc.Save(part.WorksheetCommentsPart.GetStream(FileMode.Create))
      End If
   Next
End Sub

public static void XLDeleteCommentsByUser(string fileName, string userName)
{
   const string commentsSchema = "http://schemas.openxmlformats.org/spreadsheetml/2006/main";

   using (SpreadsheetDocument doc = SpreadsheetDocument.Open(fileName, true))
   {
      //  Manage namespaces to perform XML XPath queries.
      NameTable nt = new NameTable();
      XmlNamespaceManager nsManager = new XmlNamespaceManager(nt);
      nsManager.AddNamespace("sh", commentsSchema);

      foreach (WorksheetPart part in doc.WorkbookPart.WorksheetParts)
      {
         if (part.WorksheetCommentsPart != null)
         {
            XmlDocument commentDoc = new XmlDocument();
            commentDoc.Load(part.WorksheetCommentsPart.GetStream());
            string searchString = string.Format("//sh:authors/sh:author[text()='{0}']", userName);
            XmlNode node = commentDoc.SelectSingleNode(searchString, nsManager);
            if (node != null)
            {
                XmlNodeList nodes = node.SelectNodes("preceding-sibling::sh:author", nsManager);
                int authorID = nodes.Count;

                XmlNode commentListNode = commentDoc.SelectSingleNode("sh:comments/sh:commentList", nsManager);
                if (commentListNode != null)
                {
                   searchString = string.Format("./sh:comment[@authorId='{0}']", authorID);
                   XmlNodeList comments = commentListNode.SelectNodes(searchString, nsManager);
                   foreach (System.Xml.XmlNode commentNode in comments)
                   {
                      commentListNode.RemoveChild(commentNode);
                   }
                }
            }
            //  Save the comment XML back to its part.
       commentDoc.Save(part.WorksheetCommentsPart.GetStream(FileMode.Create));
         }
      }
   }
}

Public Function XLDeleteSheet(ByVal fileName As String, ByVal sheetToDelete As String) As Boolean
   Dim returnValue As Boolean = False
   '  Open the package with read/write access.
   Dim xlDoc As SpreadsheetDocument = SpreadsheetDocument.Open(fileName, True)
   Dim doc As XmlDocument = New XmlDocument
   doc.Load(xlDoc.WorkbookPart.GetStream)
   Dim nsManager As XmlNamespaceManager = New XmlNamespaceManager(doc.NameTable)
   nsManager.AddNamespace("d", doc.DocumentElement.NamespaceURI)
   Dim searchString As String = String.Format("//d:sheet[@name='{0}']", sheetToDelete)
   Dim node As XmlNode = doc.SelectSingleNode(searchString, nsManager)
   If (Not (node) Is Nothing) Then
      Dim relationAttribute As XmlAttribute = node.Attributes("r:id")
      If (Not (relationAttribute) Is Nothing) Then
         Dim relId As String = relationAttribute.Value
         xlDoc.WorkbookPart.DeletePart(relId)
         node.ParentNode.RemoveChild(node)
         doc.Save(xlDoc.WorkbookPart.GetStream(FileMode.Create))
         returnValue = True
      End If
   End If
   Return returnValue
End Function

public static bool XLDeleteSheet(string fileName, string sheetToDelete)
{
   bool returnValue = false;
   using (SpreadsheetDocument xlDoc = SpreadsheetDocument.Open(fileName, true))
   {
      XmlDocument doc = new XmlDocument();
      doc.Load(xlDoc.WorkbookPart.GetStream());

      XmlNamespaceManager nsManager = new XmlNamespaceManager(doc.NameTable);
      nsManager.AddNamespace("d", doc.DocumentElement.NamespaceURI);

      string searchString = string.Format("//d:sheet[@name='{0}']", sheetToDelete);
      XmlNode node = doc.SelectSingleNode(searchString, nsManager);
      if (node != null)
      {
         XmlAttribute relationAttribute = node.Attributes["r:id"];
         if (relationAttribute != null)
         {
            string relId = relationAttribute.Value;
            xlDoc.WorkbookPart.DeletePart(relId);
            node.ParentNode.RemoveChild(node);
            doc.Save(xlDoc.WorkbookPart.GetStream(FileMode.Create));
            returnValue = true;
          }
      }
   }
   return returnValue;
}

Public Function XLDetectHiddenRowsOrCols(ByVal fileName As String, ByVal sheetName As String, ByVal detectRows As Boolean) As List(Of Integer)
   Const worksheetSchema As String = "http://schemas.openxmlformats.org/spreadsheetml/2006/main"
   '  Set up the return value list.
   Dim itemList As List(Of Integer) = New System.Collections.Generic.List(Of Integer)
   Dim xlDoc As SpreadsheetDocument = SpreadsheetDocument.Open(fileName, False)
   '  Load the contents of the workbook.
   Dim doc As XmlDocument = New XmlDocument
   doc.Load(xlDoc.WorkbookPart.GetStream)
   '  Create a namespace manager, so you can search.
   '  Add a prefix for the default namespace.
   Dim nsManager As XmlNamespaceManager = New XmlNamespaceManager(doc.NameTable)
   nsManager.AddNamespace("d", worksheetSchema)
   Dim searchString As String = String.Format("//d:sheet[@name='{0}']", sheetName)
   Dim sheetNode As XmlNode = doc.SelectSingleNode(searchString, nsManager)
   If (Not (sheetNode) Is Nothing) Then
      '  Get the relId attribute.
      Dim relationAttribute As XmlAttribute = sheetNode.Attributes("r:id")
      If (Not (relationAttribute) Is Nothing) Then
         Dim relId As String = relationAttribute.Value
         Dim sheetPart As WorksheetPart = CType(xlDoc.WorkbookPart.GetPartById(relId), WorksheetPart)
         '  First, get the relationship between the document and the sheet.
         '  Load the contents of the workbook.
         Dim sheetDoc As XmlDocument = New XmlDocument
         sheetDoc.Load(sheetPart.GetStream(FileMode.Open))
         If detectRows Then
             '  Retrieve the list of hidden rows.
             For Each node As System.Xml.XmlNode In sheetDoc.SelectNodes("//d:row[@hidden='1']", nsManager)
                  '  For each hidden row, add information to the output list.
                  Dim rowAttr As XmlAttribute = node.Attributes("r")
                  If (Not (rowAttr) Is Nothing) Then
                      itemList.Add(Convert.ToInt32(rowAttr.Value))
                  End If
          Next
      Else
          '  Retrieve the list of hidden columns
          For Each node As System.Xml.XmlNode In sheetDoc.SelectNodes("//d:cols/d:col", nsManager)
            Dim hiddenAttr As XmlAttribute = node.Attributes("hidden")
            If (Not (hiddenAttr) Is Nothing) Then
                If (hiddenAttr.Value = "1") Then
                   '  Get the range of columns that are hidden.
                   Dim minAttr As XmlAttribute = node.Attributes("min")
                   Dim maxAttr As XmlAttribute = node.Attributes("max")
                   If ((Not (minAttr) Is Nothing) AndAlso (Not (maxAttr) Is Nothing)) Then
                      '  Finally, add the range of values to the list.
                      Dim minValue As Integer = Convert.ToInt32(minAttr.Value)
                      Dim maxValue As Integer = Convert.ToInt32(maxAttr.Value)
                      Dim i As Integer = minValue
                      Do While (i <= maxValue)
                         itemList.Add(i)
                         i = (i + 1)
                      Loop
                   End If
                 End If
              End If
            Next
         End If
      End If
   End If
   Return itemList
End Function

public static List<int> XLDetectHiddenRowsOrCols(string fileName, string sheetName, bool detectRows)
{
   const string worksheetSchema = "http://schemas.openxmlformats.org/spreadsheetml/2006/main";

   //  Set up the return value list.
   List<int> itemList = new System.Collections.Generic.List<int>();

   using (SpreadsheetDocument xlDoc = SpreadsheetDocument.Open(fileName, false))
   {
      //  Load the contents of the workbook.
      XmlDocument doc = new XmlDocument();
      doc.Load(xlDoc.WorkbookPart.GetStream());

      //  Create a namespace manager, so you can search.
      //  Add a prefix for the default namespace.
      XmlNamespaceManager nsManager = new XmlNamespaceManager(doc.NameTable);
      nsManager.AddNamespace("d", worksheetSchema);

      string searchString = string.Format("//d:sheet[@name='{0}']", sheetName);
      XmlNode sheetNode = doc.SelectSingleNode(searchString, nsManager);
      if (sheetNode != null)
      {
          //  Get the relId attribute.
          XmlAttribute relationAttribute = sheetNode.Attributes["r:id"];
          if (relationAttribute != null)
          {
            string relId = relationAttribute.Value;

            WorksheetPart sheetPart = (WorksheetPart)xlDoc.WorkbookPart.GetPartById(relId);
            //  First, get the relationship between the document and the sheet.

            //  Load the contents of the workbook.
            XmlDocument sheetDoc = new XmlDocument();
            sheetDoc.Load(sheetPart.GetStream(FileMode.Open));

            if (detectRows)
            {
                //  Retrieve the list of hidden rows.
                foreach (System.Xml.XmlNode node in sheetDoc.SelectNodes("//d:row[@hidden='1']", nsManager))
                {
                  //  For each hidden row, add information to the output list.
                  XmlAttribute rowAttr = node.Attributes["r"];
                  if (rowAttr != null)
                  {
                      itemList.Add(Convert.ToInt32(rowAttr.Value));
                  }
                }
            }
            else
            {
               //  Retrieve the list of hidden columns.
               foreach (System.Xml.XmlNode node in sheetDoc.SelectNodes("//d:cols/d:col", nsManager))
               {
                  XmlAttribute hiddenAttr = node.Attributes["hidden"];
                  if (hiddenAttr != null)
                  {
                      if (hiddenAttr.Value == "1")
                      {
                          //  Get the range of columns that are hidden.
                          XmlAttribute minAttr = node.Attributes["min"];
                          XmlAttribute maxAttr = node.Attributes["max"];
                          if (minAttr != null && maxAttr != null)
                          {
                             //  Finally, add the range of values to the list.
                             int minValue = Convert.ToInt32(minAttr.Value);
                             int maxValue = Convert.ToInt32(maxAttr.Value);
                             for (int i = minValue; i <= maxValue; i++)
                             {
                                itemList.Add(i);
                             }
                          }
                      }
                   }
                }
             }
          }
       }
   }
   return itemList;
}

Public Sub XLExportChart(ByVal inputFileName As String, ByVal outputFileName As String, ByVal chartTitle As String)
   Const drawingMLSchema As String = "http://schemas.openxmlformats.org/drawingml/2006/main"
   Const chartMLSchema As String = "http://schemas.openxmlformats.org/drawingml/2006/chart"
   Dim chartFound As Boolean = False
   Dim xlDoc As SpreadsheetDocument = SpreadsheetDocument.Open(inputFileName, False)
   For Each sheetPart As WorksheetPart In xlDoc.WorkbookPart.WorksheetParts
      If (sheetPart.DrawingsPart Is Nothing) Then
         Continue For
      End If
      '  Loop through all the parts related to the worksheet.
      For Each chartPart As ChartPart In sheetPart.DrawingsPart.ChartParts
         '  A chart is found. Does it have the correct title?
         '  Create a namespace manager, so you can search.
         Dim nt As NameTable = New NameTable
         Dim nsManager As XmlNamespaceManager = New XmlNamespaceManager(nt)
         nsManager.AddNamespace("c", chartMLSchema)
         nsManager.AddNamespace("a", drawingMLSchema)
         '  Load the chart document from the part's stream, and 
         '  search for the requested title.
         Dim chartDoc As XmlDocument = New XmlDocument(nt)
         chartDoc.Load(chartPart.GetStream)
         Dim titleNode As XmlNode = chartDoc.SelectSingleNode("//c:chart//c:title//a:t", nsManager)
         If (Not (titleNode) Is Nothing) Then
            If (String.Compare(titleNode.InnerText, chartTitle, True) = 0) Then
               Dim newDoc As WordprocessingDocument = WordprocessingDocument.Create(outputFileName, WordprocessingDocumentType.Document)
               newDoc.AddMainDocumentPart()
            newDoc.MainDocumentPart.AddPart(Of ChartPart)(chartPart)
               '  Tell the outer loops that you are finished.
               chartFound = True
             End If
         End If
      Next
      '  Because you need to export only a single chart, exit.
      If chartFound Then
         Exit Sub
      End If
   Next
End Sub

public static void XLExportChart(string inputFileName, string outputFileName, string chartTitle)
{
   const string drawingMLSchema = "http://schemas.openxmlformats.org/drawingml/2006/main";
   const string chartMLSchema = "http://schemas.openxmlformats.org/drawingml/2006/chart";

   bool chartFound = false;

   using (SpreadsheetDocument xlDoc = SpreadsheetDocument.Open(inputFileName, false))
   {
      foreach (WorksheetPart sheetPart in xlDoc.WorkbookPart.WorksheetParts)
      {
          if (sheetPart.DrawingsPart == null)
            continue;
          //  Loop through all the parts related to the worksheet.
          foreach (ChartPart chartPart in sheetPart.DrawingsPart.ChartParts)
          {
              //  A chart is found. Does it have the correct title?      

              //  Create a namespace manager, so you can search.
              NameTable nt = new NameTable();
              XmlNamespaceManager nsManager = new XmlNamespaceManager(nt);
              nsManager.AddNamespace("c", chartMLSchema);
              nsManager.AddNamespace("a", drawingMLSchema);

              //  Load the chart document from the part's stream, and 
              //  search for the requested title.
              XmlDocument chartDoc = new XmlDocument(nt);
              chartDoc.Load(chartPart.GetStream());

              XmlNode titleNode = chartDoc.SelectSingleNode("//c:chart//c:title//a:t", nsManager);
              if (titleNode != null)
              {
                 if (string.Compare(titleNode.InnerText, chartTitle, true) == 0)
                 {
                    using (WordprocessingDocument newDoc = WordprocessingDocument.Create(outputFileName, WordprocessingDocumentType.Document))
                    {
                        newDoc.AddMainDocumentPart();
                        newDoc.MainDocumentPart.AddPart<ChartPart>(chartPart);
                    }

                    //  Tell the outer loops that you are finished.
                    chartFound = true;
                 }
            }
          }
          //  You need to export only a single chart, so get out now.
          if (chartFound)
          {
            break;
          }
      }
   }
}

Public Function XLGetHiddenSheets(ByVal fileName As String) As List(Of String)
   Dim sheets As List(Of String) = New List(Of String)()
   Dim xlDoc As SpreadsheetDocument = SpreadsheetDocument.Open(fileName, False)
   '  Get the main document part (workbook.xml).
   Dim doc As XmlDocument = New XmlDocument
   doc.Load(xlDoc.WorkbookPart.GetStream)
   '  Create a NamespaceManager to handle the default namespace, 
   '  and create a prefix for the default namespace.
   Dim nsManager As XmlNamespaceManager = New XmlNamespaceManager(doc.NameTable)
   nsManager.AddNamespace("default", doc.DocumentElement.NamespaceURI)
   For Each node As System.Xml.XmlNode In doc.SelectNodes("//default:sheets//default:sheet[@state='hidden']", nsManager)
      Dim sheetName As String = node.Attributes("name").Value
      sheets.Add(sheetName)
   Next
   Return sheets
End Function

public static List<string> XLGetHiddenSheets(string fileName)
{
   List<string> sheets = new List<string>();

   using (SpreadsheetDocument xlDoc = SpreadsheetDocument.Open(fileName, false))
   {
      //  Get the main document part (workbook.xml).
      XmlDocument doc = new XmlDocument();
      doc.Load(xlDoc.WorkbookPart.GetStream());

      //  Create a NamespaceManager to handle the default namespace, 
      //  and create a prefix for the default namespace.
      XmlNamespaceManager nsManager = new XmlNamespaceManager(doc.NameTable);
      nsManager.AddNamespace("default", doc.DocumentElement.NamespaceURI);

      foreach (System.Xml.XmlNode node in doc.SelectNodes("//default:sheets//default:sheet[@state='hidden']", nsManager))
      {
         string sheetName = node.Attributes["name"].Value;
         sheets.Add(sheetName);
      }
   }
   return sheets;
}

Public Function XLGetCellValue(ByVal fileName As String, ByVal sheetName As String, ByVal addressName As String) As String
   Const worksheetSchema As String = "http://schemas.openxmlformats.org/spreadsheetml/2006/main"
   Const sharedStringSchema As String = "http://schemas.openxmlformats.org/spreadsheetml/2006/main"
   Dim cellValue As String = Nothing
   '  Retrieve the stream containing the requested
   '  worksheet's information.
   Dim xlDoc As SpreadsheetDocument = SpreadsheetDocument.Open(fileName, False)
   '  Get the main document part (workbook.xml).
   Dim doc As XmlDocument = New XmlDocument
   doc.Load(xlDoc.WorkbookPart.GetStream)
   '  Create a namespace manager, so you can search.
   '  Add a prefix (d) for the default namespace.
   Dim nt As NameTable = New NameTable
   Dim nsManager As XmlNamespaceManager = New XmlNamespaceManager(nt)
   nsManager.AddNamespace("d", worksheetSchema)
   nsManager.AddNamespace("s", sharedStringSchema)
   Dim searchString As String = String.Format("//d:sheet[@name='{0}']", sheetName)
   Dim sheetNode As XmlNode = doc.SelectSingleNode(searchString, nsManager)
   If (Not (sheetNode) Is Nothing) Then
      '  Get the relId attribute.
      Dim relationAttribute As XmlAttribute = sheetNode.Attributes("r:id")
      If (Not (relationAttribute) Is Nothing) Then
         Dim relId As String = relationAttribute.Value
         '  Load the contents of the workbook.
         Dim sheetDoc As XmlDocument = New XmlDocument(nt)
         sheetDoc.Load(xlDoc.WorkbookPart.GetPartById(relId).GetStream)
         Dim cellNode As XmlNode = sheetDoc.SelectSingleNode(String.Format("//d:sheetData/d:row/d:c[@r='{0}']", addressName), nsManager)
         If (Not (cellNode) Is Nothing) Then
            Dim typeAttr As XmlAttribute = cellNode.Attributes("t")
            Dim cellType As String = String.Empty
            If (Not (typeAttr) Is Nothing) Then
               cellType = typeAttr.Value
            End If
            Dim valueNode As XmlNode = cellNode.SelectSingleNode("d:v", nsManager)
            If (Not (valueNode) Is Nothing) Then
               cellValue = valueNode.InnerText
            End If
            If (cellType = "b") Then
               If (cellValue = "1") Then
                  cellValue = "TRUE"
               Else
                  cellValue = "FALSE"
               End If
            ElseIf (cellType = "s") Then
               If (Not (xlDoc.WorkbookPart.SharedStringTablePart) Is Nothing) Then
                   Dim stringDoc As XmlDocument = New XmlDocument(nt)
                   stringDoc.Load(xlDoc.WorkbookPart.SharedStringTablePart.GetStream)
                   '  Add the string schema to the namespace manager.
                   nsManager.AddNamespace("s", sharedStringSchema)
                   Dim requestedString As Integer = Convert.ToInt32(cellValue)
                   Dim strSearch As String = String.Format("//s:sst/s:si[{0}]", (requestedString + 1))
                   Dim stringNode As XmlNode = stringDoc.SelectSingleNode(strSearch, nsManager)
                   If (Not (stringNode) Is Nothing) Then
                      cellValue = stringNode.InnerText
                   End If
                End If
            End If
         End If
      End If
   End If
   Return cellValue
End Function

public static string XLGetCellValue(string fileName, string sheetName, string addressName)
{
   const string worksheetSchema = "http://schemas.openxmlformats.org/spreadsheetml/2006/main";
   const string sharedStringSchema = "http://schemas.openxmlformats.org/spreadsheetml/2006/main";

   string cellValue = null;

   //  Retrieve the stream containing the requested
   //  worksheet's info.
   using (SpreadsheetDocument xlDoc = SpreadsheetDocument.Open(fileName, false))
   {
      //  Get the main document part (workbook.xml).
      XmlDocument doc = new XmlDocument();
      doc.Load(xlDoc.WorkbookPart.GetStream());

      //  Create a namespace manager, so you can search.
      //  Add a prefix (d) for the default namespace.
      NameTable nt = new NameTable();
      XmlNamespaceManager nsManager = new XmlNamespaceManager(nt);
      nsManager.AddNamespace("d", worksheetSchema);
      nsManager.AddNamespace("s", sharedStringSchema);

      string searchString = string.Format("//d:sheet[@name='{0}']", sheetName);
      XmlNode sheetNode = doc.SelectSingleNode(searchString, nsManager);
      if (sheetNode != null)
      {
         //  Get the relId attribute.
          XmlAttribute relationAttribute = sheetNode.Attributes["r:id"];
         if (relationAttribute != null)
         {
            string relId = relationAttribute.Value;
            //  Load the contents of the workbook.
            XmlDocument sheetDoc = new XmlDocument(nt);
            sheetDoc.Load(xlDoc.WorkbookPart.GetPartById(relId).GetStream());

            XmlNode cellNode = sheetDoc.SelectSingleNode(string.Format("//d:sheetData/d:row/d:c[@r='{0}']", addressName), nsManager);
            if (cellNode != null)
            {
               XmlAttribute typeAttr = cellNode.Attributes["t"];
               string cellType = string.Empty;
               if (typeAttr != null)
               {
                  cellType = typeAttr.Value;
               }

               XmlNode valueNode = cellNode.SelectSingleNode("d:v", nsManager);
               if (valueNode != null)
               {
                  cellValue = valueNode.InnerText;
               }
               if (cellType == "b")
               {
                  if (cellValue == "1")
                  {
                     cellValue = "TRUE";
                  }
                  else
                  {
                     cellValue = "FALSE";
                  }
               }
               else if (cellType == "s")
               {
                   if (xlDoc.WorkbookPart.SharedStringTablePart != null)
                   {
                      XmlDocument stringDoc = new XmlDocument(nt);
                      stringDoc.Load(xlDoc.WorkbookPart.SharedStringTablePart.GetStream());
                      //  Add the string schema to the namespace manager.
                      nsManager.AddNamespace("s", sharedStringSchema);

                      int requestedString = Convert.ToInt32(cellValue);
                      string strSearch = string.Format("//s:sst/s:si[{0}]", requestedString + 1);
                      XmlNode stringNode = stringDoc.SelectSingleNode(strSearch, nsManager);
                      if (stringNode != null)
                      {
                          cellValue = stringNode.InnerText;
                      }
                   }
                }
            }
         }
       }
   }
   return cellValue;
}