source: branches/ExportSymbolicDataAnalysisSolutions/HeuristicLab.ExtLibs/HeuristicLab.EPPlus/3.1.3/EPPlus-3.1.3/ExcelWorkbook.cs @ 9580

/*******************************************************************************
 * You may amend and distribute as you like, but don't remove this header!
 *
 * EPPlus provides server-side generation of Excel 2007/2010 spreadsheets.
 * See http://www.codeplex.com/EPPlus for details.
 *
 * Copyright (C) 2011  Jan Källman
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.

 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  
 * See the GNU Lesser General Public License for more details.
 *
 * The GNU Lesser General Public License can be viewed at http://www.opensource.org/licenses/lgpl-license.php
 * If you unfamiliar with this license or have questions about it, here is an http://www.gnu.org/licenses/gpl-faq.html
 *
 * All code and executables are provided "as is" with no warranty either express or implied. 
 * The author accepts no liability for any damage or loss of business that this product may cause.
 *
 * Code change notes:
 * 
 * Author             Change            Date
 * ******************************************************************************
 * Jan Källman        Initial Release          2011-01-01
 * Jan Källman        License changed GPL-->LGPL 2011-12-27
 *******************************************************************************/
using System;
using System.Xml;
using System.IO;
using System.IO.Packaging;
using System.Collections.Generic;
using System.Text;
using System.Security;
using System.Globalization;
using System.Text.RegularExpressions;
using OfficeOpenXml.VBA;
using System.Drawing;
namespace OfficeOpenXml
{
  #region Public Enum ExcelCalcMode
  /// <summary>
  /// How the application should calculate formulas in the workbook
  /// </summary>
  public enum ExcelCalcMode
  {
    /// <summary>
    /// Indicates that calculations in the workbook are performed automatically when cell values change. 
    /// The application recalculates those cells that are dependent on other cells that contain changed values. 
    /// This mode of calculation helps to avoid unnecessary calculations.
    /// </summary>
    Automatic,
    /// <summary>
    /// Indicates tables be excluded during automatic calculation
    /// </summary>
    AutomaticNoTable,
    /// <summary>
    /// Indicates that calculations in the workbook be triggered manually by the user. 
    /// </summary>
    Manual
  }
  #endregion

  /// <summary>
  /// Represents the Excel workbook and provides access to all the 
  /// document properties and worksheets within the workbook.
  /// </summary>
  public sealed class ExcelWorkbook : XmlHelper
  {
    internal class SharedStringItem
    {
      internal int pos;
      internal string Text;
      internal bool isRichText = false;
    }
    #region Private Properties
    internal ExcelPackage _package;
    private ExcelWorksheets _worksheets;
    private OfficeProperties _properties;

    private ExcelStyles _styles;
    #endregion

    #region ExcelWorkbook Constructor
    /// <summary>
    /// Creates a new instance of the ExcelWorkbook class.
    /// </summary>
    /// <param name="package">The parent package</param>
    /// <param name="namespaceManager">NamespaceManager</param>
    internal ExcelWorkbook(ExcelPackage package, XmlNamespaceManager namespaceManager) :
      base(namespaceManager)
    {
      _package = package;
      WorkbookUri = new Uri("/xl/workbook.xml", UriKind.Relative);
      SharedStringsUri = new Uri("/xl/sharedStrings.xml", UriKind.Relative);
      StylesUri = new Uri("/xl/styles.xml", UriKind.Relative);

      _names = new ExcelNamedRangeCollection(this);
      _namespaceManager = namespaceManager;
      TopNode = WorkbookXml.DocumentElement;
      SchemaNodeOrder = new string[] { "fileVersion", "fileSharing", "workbookPr", "workbookProtection", "bookViews", "sheets", "functionGroups", "functionPrototypes", "externalReferences", "definedNames", "calcPr", "oleSize", "customWorkbookViews", "pivotCaches", "smartTagPr", "smartTagTypes", "webPublishing", "fileRecoveryPr", };
      GetSharedStrings();
    }
    #endregion

    internal Dictionary<string, SharedStringItem> _sharedStrings = new Dictionary<string, SharedStringItem>(); //Used when reading cells.
    internal List<SharedStringItem> _sharedStringsList = new List<SharedStringItem>(); //Used when reading cells.
    internal ExcelNamedRangeCollection _names;
    internal int _nextDrawingID = 0;
    internal int _nextTableID = 1;
    internal int _nextPivotTableID = 1;
    internal XmlNamespaceManager _namespaceManager;
    /// <summary>
    /// Read shared strings to list
    /// </summary>
    private void GetSharedStrings()
    {
      if (_package.Package.PartExists(SharedStringsUri))
      {
        var xml = _package.GetXmlFromUri(SharedStringsUri);
        XmlNodeList nl = xml.SelectNodes("//d:sst/d:si", NameSpaceManager);
        _sharedStringsList = new List<SharedStringItem>();
        if (nl != null)
        {
          foreach (XmlNode node in nl)
          {
            XmlNode n = node.SelectSingleNode("d:t", NameSpaceManager);
            if (n != null)
            {
              _sharedStringsList.Add(new SharedStringItem() { Text = ExcelDecodeString(n.InnerText) });
            }
            else
            {
              _sharedStringsList.Add(new SharedStringItem() { Text = node.InnerXml, isRichText = true });
            }
          }
        }
      }
    }
    internal void GetDefinedNames()
    {
      XmlNodeList nl = WorkbookXml.SelectNodes("//d:definedNames/d:definedName", NameSpaceManager);
      if (nl != null)
      {
        foreach (XmlElement elem in nl)
        { 
          string fullAddress = elem.InnerText;

          int localSheetID;
          ExcelWorksheet nameWorksheet;
          if(!int.TryParse(elem.GetAttribute("localSheetId"), out localSheetID))
          {
            localSheetID = -1;
            nameWorksheet=null;
          }
          else
          {
            nameWorksheet=Worksheets[localSheetID + 1];
          }
          var addressType = ExcelAddressBase.IsValid(fullAddress);
          ExcelRangeBase range;
          ExcelNamedRange namedRange;

          if (fullAddress.IndexOf("[") > -1)
          {
            int start = fullAddress.IndexOf("[");
            int end = fullAddress.IndexOf("]", start);
            if (start >= 0 && end >= 0)
            {

              string externalIndex = fullAddress.Substring(start + 1, end - start - 1);
              int index;
              if (int.TryParse(externalIndex, out index))
              {
                if (index > 0 && index <= _externalReferences.Count)
                {
                  fullAddress = fullAddress.Substring(0, start) + "[" + _externalReferences[index - 1] + "]" + fullAddress.Substring(end + 1);
                }
              }
            }
          }

          if (addressType == ExcelAddressBase.AddressType.Invalid || addressType == ExcelAddressBase.AddressType.InternalName || addressType == ExcelAddressBase.AddressType.ExternalName)    //A value or a formula
          {
            double value;
            range = new ExcelRangeBase(this, nameWorksheet, elem.GetAttribute("name"), true);
            if (nameWorksheet == null)
            {
              namedRange = _names.Add(elem.GetAttribute("name"), range);
            }
            else
            {
              namedRange = nameWorksheet.Names.Add(elem.GetAttribute("name"), range);
            }
            
            if (fullAddress.StartsWith("\"")) //String value
            {
              namedRange.NameValue = fullAddress.Substring(1,fullAddress.Length-2);
            }
            else if (double.TryParse(fullAddress, NumberStyles.Any, CultureInfo.InvariantCulture, out value))
            {
              namedRange.NameValue = value;
            }
            else
            {
              namedRange.NameFormula = fullAddress;
            }
          }
          else
          {
            ExcelAddress addr = new ExcelAddress(fullAddress);
            if (localSheetID > -1)
            {
              if (string.IsNullOrEmpty(addr._ws))
              {
                namedRange = Worksheets[localSheetID + 1].Names.Add(elem.GetAttribute("name"), new ExcelRangeBase(this, Worksheets[localSheetID + 1], fullAddress, false));
              }
              else
              {
                namedRange = Worksheets[localSheetID + 1].Names.Add(elem.GetAttribute("name"), new ExcelRangeBase(this, Worksheets[addr._ws], fullAddress, false));
              }
            }
            else
            {
              var ws = Worksheets[addr._ws];
              namedRange = _names.Add(elem.GetAttribute("name"), new ExcelRangeBase(this, ws, fullAddress, false));
            }
          }
          if (elem.GetAttribute("hidden") == "1" && namedRange != null) namedRange.IsNameHidden = true;
          if(!string.IsNullOrEmpty(elem.GetAttribute("comment"))) namedRange.NameComment=elem.GetAttribute("comment");
        }
      }
    }
    #region Worksheets
    /// <summary>
    /// Provides access to all the worksheets in the workbook.
    /// </summary>
    public ExcelWorksheets Worksheets
    {
      get
      {
        if (_worksheets == null)
        {
          var sheetsNode = _workbookXml.DocumentElement.SelectSingleNode("d:sheets", _namespaceManager);
          if (sheetsNode == null)
          {
            sheetsNode = CreateNode("d:sheets");
          }
          
          _worksheets = new ExcelWorksheets(_package, _namespaceManager, sheetsNode);
        }
        return (_worksheets);
      }
    }
    #endregion

    /// <summary>
    /// Provides access to named ranges
    /// </summary>
    public ExcelNamedRangeCollection Names
    {
      get
      {
        return _names;
      }
    }
    #region Workbook Properties
    decimal _standardFontWidth = decimal.MinValue;
        string fontID = "";
    /// <summary>
    /// Max font width for the workbook
        /// <remarks>This method uses GDI. If you use Asure or another environment that does not support GDI, you have to set this value manually if you don't use the standard Calibri font</remarks>
    /// </summary>
    public decimal MaxFontWidth 
    {
      get
      {
                if (_standardFontWidth == decimal.MinValue || fontID != Styles.Fonts[0].Id)
        {
          var font = Styles.Fonts[0];
                    try
                    {
                        Font f = new Font(font.Name, font.Size);
                        fontID = font.Id;
                        using (Bitmap b = new Bitmap(1, 1))
                        {
                            using (Graphics g = Graphics.FromImage(b))
                            {
                                _standardFontWidth = (decimal)Math.Truncate(g.MeasureString("00", f).Width - g.MeasureString("0", f).Width);
                            }
                        }
                        if (_standardFontWidth <= 0) //No GDI?
                        {
                            _standardFontWidth = (int)(font.Size * (2D / 3D)); //Aprox. for Calibri.
                        }
                    }
                    catch   //Error, set default value
                    {
                        _standardFontWidth = (int)(font.Size * (2D / 3D)); //Aprox for Calibri.
                    }
        }
        return _standardFontWidth;
      }
            set
            {
                _standardFontWidth = value;
            }
    }
    ExcelProtection _protection = null;
    /// <summary>
    /// Access properties to protect or unprotect a workbook
    /// </summary>
    public ExcelProtection Protection
    {
      get
      {
        if (_protection == null)
        {
          _protection = new ExcelProtection(NameSpaceManager, TopNode, this);
          _protection.SchemaNodeOrder = SchemaNodeOrder;
        }
        return _protection;
      }
    }
    ExcelWorkbookView _view = null;
    /// <summary>
    /// Access to workbook view properties
    /// </summary>
    public ExcelWorkbookView View
    {
      get
      {
        if (_view == null)
        {
          _view = new ExcelWorkbookView(NameSpaceManager, TopNode, this);
        }
        return _view;
      }
    }
        ExcelVbaProject _vba = null;
        /// <summary>
        /// A reference to the VBA project.
        /// Null if no project exists.
        /// User Workbook.CreateVBAProject to create a new VBA-Project
        /// </summary>
        public ExcelVbaProject VbaProject
        {
            get
            {
                if (_vba == null)
                {
                    if(_package.Package.PartExists(new Uri(ExcelVbaProject.PartUri, UriKind.Relative)))
                    {
                        _vba = new ExcelVbaProject(this);
                    }
                }
                return _vba;
            }
        }
        /// <summary>
        /// Create an empty VBA project.
        /// </summary>
        public void CreateVBAProject()
        {
            if (_vba != null || _package.Package.PartExists(new Uri(ExcelVbaProject.PartUri, UriKind.Relative)))
            {
                throw (new InvalidOperationException("VBA project already exists."));
            }
                        
            _vba = new ExcelVbaProject(this);
            _vba.Create();
        }
    /// <summary>
    /// URI to the workbook inside the package
    /// </summary>
    internal Uri WorkbookUri { get; private set; }
    /// <summary>
        /// URI to the styles inside the package
    /// </summary>
    internal Uri StylesUri { get; private set; }
    /// <summary>
        /// URI to the shared strings inside the package
    /// </summary>
    internal Uri SharedStringsUri { get; private set; }
    /// <summary>
    /// Returns a reference to the workbook's part within the package
    /// </summary>
    internal PackagePart Part { get { return (_package.Package.GetPart(WorkbookUri)); } }
    
    #region WorkbookXml
    private XmlDocument _workbookXml;
    /// <summary>
    /// Provides access to the XML data representing the workbook in the package.
    /// </summary>
    public XmlDocument WorkbookXml
    {
      get
      {
        if (_workbookXml == null)
        {
          CreateWorkbookXml(_namespaceManager);
        }
        return (_workbookXml);
      }
    }
        const string codeModuleNamePath = "d:workbookPr/@codeName";
        internal string CodeModuleName
        {
            get
            {
                return GetXmlNodeString(codeModuleNamePath);
            }
            set
            {
                SetXmlNodeString(codeModuleNamePath,value);
            }
        }
        internal void CodeNameChange(string value)
        {
            CodeModuleName = value;
        }
        public VBA.ExcelVBAModule CodeModule
        {
            get
            {
                if (VbaProject != null)
                {
                    return VbaProject.Modules[CodeModuleName];
                }
                else
                {
                    return null;
                }
            }
        }
    /// <summary>
    /// Create or read the XML for the workbook.
    /// </summary>
    private void CreateWorkbookXml(XmlNamespaceManager namespaceManager)
    {
      if (_package.Package.PartExists(WorkbookUri))
        _workbookXml = _package.GetXmlFromUri(WorkbookUri);
      else
      {
        // create a new workbook part and add to the package
        PackagePart partWorkbook = _package.Package.CreatePart(WorkbookUri, @"application/vnd.openxmlformats-officedocument.spreadsheetml.sheet.main+xml", _package.Compression);

        // create the workbook
        _workbookXml = new XmlDocument(namespaceManager.NameTable);                
        
        _workbookXml.PreserveWhitespace = ExcelPackage.preserveWhitespace;
        // create the workbook element
        XmlElement wbElem = _workbookXml.CreateElement("workbook", ExcelPackage.schemaMain);

        // Add the relationships namespace
        wbElem.SetAttribute("xmlns:r", ExcelPackage.schemaRelationships);

        _workbookXml.AppendChild(wbElem);

        // create the bookViews and workbooks element
        XmlElement bookViews = _workbookXml.CreateElement("bookViews", ExcelPackage.schemaMain);
        wbElem.AppendChild(bookViews);
        XmlElement workbookView = _workbookXml.CreateElement("workbookView", ExcelPackage.schemaMain);
        bookViews.AppendChild(workbookView);

        // save it to the package
        StreamWriter stream = new StreamWriter(partWorkbook.GetStream(FileMode.Create, FileAccess.Write));
        _workbookXml.Save(stream);
        stream.Close();
        _package.Package.Flush();
      }
    }
    #endregion
    #region StylesXml
    private XmlDocument _stylesXml;
    /// <summary>
    /// Provides access to the XML data representing the styles in the package. 
    /// </summary>
    public XmlDocument StylesXml
    {
      get
      {
        if (_stylesXml == null)
        {
          if (_package.Package.PartExists(StylesUri))
            _stylesXml = _package.GetXmlFromUri(StylesUri);
          else
          {
            // create a new styles part and add to the package
            PackagePart part = _package.Package.CreatePart(StylesUri, @"application/vnd.openxmlformats-officedocument.spreadsheetml.styles+xml", _package.Compression);
            // create the style sheet

            StringBuilder xml = new StringBuilder("<styleSheet xmlns=\"http://schemas.openxmlformats.org/spreadsheetml/2006/main\">");
            xml.Append("<numFmts />");
            xml.Append("<fonts count=\"1\"><font><sz val=\"11\" /><name val=\"Calibri\" /></font></fonts>");
            xml.Append("<fills><fill><patternFill patternType=\"none\" /></fill><fill><patternFill patternType=\"gray125\" /></fill></fills>");
            xml.Append("<borders><border><left /><right /><top /><bottom /><diagonal /></border></borders>");
            xml.Append("<cellStyleXfs count=\"1\"><xf numFmtId=\"0\" fontId=\"0\" /></cellStyleXfs>");
            xml.Append("<cellXfs count=\"1\"><xf numFmtId=\"0\" fontId=\"0\" xfId=\"0\" /></cellXfs>");
            xml.Append("<cellStyles><cellStyle name=\"Normal\" xfId=\"0\" builtinId=\"0\" /></cellStyles>");
                        xml.Append("<dxfs count=\"0\" />");
                        xml.Append("</styleSheet>");
            
            _stylesXml = new XmlDocument();
            _stylesXml.LoadXml(xml.ToString());
            
            //Save it to the package
            StreamWriter stream = new StreamWriter(part.GetStream(FileMode.Create, FileAccess.Write));

            _stylesXml.Save(stream);
            stream.Close();
            _package.Package.Flush();

            // create the relationship between the workbook and the new shared strings part
            _package.Workbook.Part.CreateRelationship(PackUriHelper.GetRelativeUri(WorkbookUri, StylesUri), TargetMode.Internal, ExcelPackage.schemaRelationships + "/styles");
            _package.Package.Flush();
          }
        }
        return (_stylesXml);
      }
      set
      {
        _stylesXml = value;
      }
    }
    /// <summary>
    /// Package styles collection. Used internally to access style data.
    /// </summary>
    public ExcelStyles Styles
    {
      get
      {
        if (_styles == null)
        {
          _styles = new ExcelStyles(NameSpaceManager, StylesXml, this);
        }
        return _styles;
      }
    }
    #endregion

    #region Office Document Properties
    /// <summary>
    /// The office document properties
    /// </summary>
    public OfficeProperties Properties
    {
      get 
      {
        if (_properties == null)
        {
          //  Create a NamespaceManager to handle the default namespace, 
          //  and create a prefix for the default namespace:                   
          _properties = new OfficeProperties(_package, NameSpaceManager);
        }
        return _properties;
      }
    }
    #endregion

    #region CalcMode
    private string CALC_MODE_PATH = "d:calcPr/@calcMode";
    /// <summary>
    /// Calculation mode for the workbook.
    /// </summary>
    public ExcelCalcMode CalcMode
    {
      get
      {
        string calcMode = GetXmlNodeString(CALC_MODE_PATH);
        switch (calcMode)
        {
          case "autoNoTable":
            return ExcelCalcMode.AutomaticNoTable;
          case "manual":
            return ExcelCalcMode.Manual;
          default:
            return ExcelCalcMode.Automatic;

        }
      }
      set
      {
        switch (value)
        {
          case ExcelCalcMode.AutomaticNoTable:
            SetXmlNodeString(CALC_MODE_PATH, "autoNoTable") ;
            break;
          case ExcelCalcMode.Manual:
            SetXmlNodeString(CALC_MODE_PATH, "manual");
            break;
          default:
            SetXmlNodeString(CALC_MODE_PATH, "auto");
            break;

        }
      }
      #endregion
    }
    #endregion
    #region Workbook Private Methods
      
    #region Save // Workbook Save
    /// <summary>
    /// Saves the workbook and all its components to the package.
    /// For internal use only!
    /// </summary>
    internal void Save()  // Workbook Save
    {
      if (Worksheets.Count == 0)
        throw new InvalidOperationException("The workbook must contain at least one worksheet");

      DeleteCalcChain();

            if (VbaProject == null)
            {
                if (Part.ContentType != ExcelPackage.contentTypeWorkbookDefault)
                {
                    ChangeContentTypeWorkbook(ExcelPackage.contentTypeWorkbookDefault);
                }
            }
            else
            {
                if (Part.ContentType != ExcelPackage.contentTypeWorkbookMacroEnabled)
                {
                    ChangeContentTypeWorkbook(ExcelPackage.contentTypeWorkbookMacroEnabled);
                }
            }
      
      UpdateDefinedNamesXml();

      // save the workbook
      if (_workbookXml != null)
      {
        _package.SavePart(WorkbookUri, _workbookXml);
      }

      // save the properties of the workbook
      if (_properties != null)
      {
        _properties.Save();
      }

      // save the style sheet
      Styles.UpdateXml();
      _package.SavePart(StylesUri, _stylesXml);

      // save all the open worksheets
      var isProtected = Protection.LockWindows || Protection.LockStructure;
      foreach (ExcelWorksheet worksheet in Worksheets)
      {
        if (isProtected && Protection.LockWindows)
        {
          worksheet.View.WindowProtection = true;
        }
        worksheet.Save();
      }
      
      UpdateSharedStringsXml();
      
      // Data validation
      ValidateDataValidations();

            //VBA
            if (VbaProject!=null)
            {
                VbaProject.Save();
            }

    }
        /// <summary>
        /// Recreate the workbook part with a new contenttype
        /// </summary>
        /// <param name="contentType">The new contenttype</param>
        private void ChangeContentTypeWorkbook(string contentType)
        {            
            var p=_package.Package;
            var part = Part;
            var rels = part.GetRelationships();

            p.DeletePart(WorkbookUri);
            part = p.CreatePart(WorkbookUri, contentType);
            
            foreach (var rel in rels)
            {
                p.DeleteRelationship(rel.Id);
                var newRel=part.CreateRelationship(rel.TargetUri, rel.TargetMode, rel.RelationshipType);
                if (rel.RelationshipType.EndsWith("worksheet"))
                {
                    var sheetNode = (XmlElement)WorkbookXml.SelectSingleNode(string.Format("d:workbook/d:sheets/d:sheet[@r:id='{0}']", rel.Id), NameSpaceManager);
                    sheetNode.SetAttribute("id", ExcelPackage.schemaRelationships, newRel.Id);
                }
                else if (rel.RelationshipType.EndsWith("pivotCacheDefinition"))
                {
                    var sheetNode = (XmlElement)WorkbookXml.SelectSingleNode(string.Format("d:workbook/d:pivotCaches/d:pivotCache[@r:id='{0}']", rel.Id), NameSpaceManager);
                    sheetNode.SetAttribute("id", ExcelPackage.schemaRelationships, newRel.Id);
                }
            }
        }

    private void DeleteCalcChain()
    {
      //Remove the calc chain if it exists.
      Uri uriCalcChain = new Uri("/xl/calcChain.xml", UriKind.Relative);
      if (_package.Package.PartExists(uriCalcChain))
      {
        Uri calcChain = new Uri("calcChain.xml", UriKind.Relative);
        foreach (PackageRelationship relationship in _package.Workbook.Part.GetRelationships())
        {
          if (relationship.TargetUri == calcChain)
          {
            _package.Workbook.Part.DeleteRelationship(relationship.Id);
            break;
          }
        }
        // delete the calcChain part
        _package.Package.DeletePart(uriCalcChain);
      }
    }

    private void ValidateDataValidations()
    {
      foreach (var sheet in _package.Workbook.Worksheets)
      {
        sheet.DataValidations.ValidateAll();
      }
    }

    private void UpdateSharedStringsXml()
    {
      PackagePart stringPart;
      if (_package.Package.PartExists(SharedStringsUri))
      {
        stringPart=_package.Package.GetPart(SharedStringsUri);
      }
      else
      {
        stringPart = _package.Package.CreatePart(SharedStringsUri, @"application/vnd.openxmlformats-officedocument.spreadsheetml.sharedStrings+xml", _package.Compression);
        Part.CreateRelationship(PackUriHelper.GetRelativeUri(WorkbookUri, SharedStringsUri), TargetMode.Internal, ExcelPackage.schemaRelationships + "/sharedStrings");
      }

      StreamWriter sw = new StreamWriter(stringPart.GetStream(FileMode.Create, FileAccess.Write));
      sw.Write("<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\" ?><sst xmlns=\"http://schemas.openxmlformats.org/spreadsheetml/2006/main\" count=\"{0}\" uniqueCount=\"{0}\">", _sharedStrings.Count);
      foreach (string t in _sharedStrings.Keys)
      {

        SharedStringItem ssi = _sharedStrings[t];
        if (ssi.isRichText)
        {
          sw.Write("<si>");
          ExcelEncodeString(sw, t);
          sw.Write("</si>");
        }
        else
        {
          if (t.Length>0 && (t[0] == ' ' || t[t.Length-1] == ' ' || t.Contains("  ") || t.Contains("\t")))
          {
            sw.Write("<si><t xml:space=\"preserve\">");
          }
          else
          {
            sw.Write("<si><t>");
          }
          ExcelEncodeString(sw, SecurityElement.Escape(t));
          sw.Write("</t></si>");
        }
      }
      sw.Write("</sst>");
      sw.Flush();
    }

    /// <summary>
    /// Return true if preserve space attribute is set.
    /// </summary>
    /// <param name="sw"></param>
    /// <param name="t"></param>
    /// <returns></returns>
    private void ExcelEncodeString(StreamWriter sw, string t)
    {
      if(Regex.IsMatch(t, "(_x[0-9A-F]{4,4}_)"))
      {
        var match = Regex.Match(t, "(_x[0-9A-F]{4,4}_)");
        int indexAdd = 0;
        while (match.Success)
        {
          t=t.Insert(match.Index + indexAdd, "_x005F");
          indexAdd += 6;
          match = match.NextMatch();
        }
      }
      for (int i=0;i<t.Length;i++)
      {
        if (t[i] <= 0x1f && t[i] != '\t' && t[i] != '\n' && t[i] != '\r') //Not Tab, CR or LF
        {
          sw.Write("_x00{0}_", (t[i] < 0xa ? "0" : "") + ((int)t[i]).ToString("X"));                    
        }
        else
        {
          sw.Write(t[i]);
        }
      }

    }
    private string ExcelDecodeString(string t)
    {
      var match = Regex.Match(t, "(_x005F|_x[0-9A-F]{4,4}_)");
      if(!match.Success) return t;

      bool useNextValue = false;
      StringBuilder ret=new StringBuilder();
      int prevIndex=0;
      while(match.Success)
      {
        if (prevIndex < match.Index) ret.Append(t.Substring(prevIndex, match.Index - prevIndex));
        if (!useNextValue && match.Value == "_x005F")
        {
          useNextValue = true;
        }
        else
        {
          if (useNextValue)
          {
            ret.Append(match.Value);
            useNextValue=false;
          }
          else
          {
            ret.Append((char)int.Parse(match.Value.Substring(2,4),NumberStyles.AllowHexSpecifier));
          }
        }
        prevIndex=match.Index+match.Length;
        match = match.NextMatch();
      }
      ret.Append(t.Substring(prevIndex, t.Length - prevIndex));
      return ret.ToString();
    }
    private void UpdateDefinedNamesXml()
    {
      try
      {
        XmlNode top = WorkbookXml.SelectSingleNode("//d:definedNames", NameSpaceManager);
        if (!ExistsNames())
        {
          if (top != null) TopNode.RemoveChild(top);
          return;
        }
        else
        {
          if (top == null)
          {
            CreateNode("d:definedNames");
            top = WorkbookXml.SelectSingleNode("//d:definedNames", NameSpaceManager);
          }
          else
          {
            top.RemoveAll();
          }
          foreach (ExcelNamedRange name in _names)
          {

            XmlElement elem = WorkbookXml.CreateElement("definedName", ExcelPackage.schemaMain);
            top.AppendChild(elem);
            elem.SetAttribute("name", name.Name);
            if (name.IsNameHidden) elem.SetAttribute("hidden", "1");
            if (!string.IsNullOrEmpty(name.NameComment)) elem.SetAttribute("comment", name.NameComment);
            SetNameElement(name, elem);
          }
        }
        foreach (ExcelWorksheet ws in _worksheets)
        {
          foreach (ExcelNamedRange name in ws.Names)
          {

            XmlElement elem = WorkbookXml.CreateElement("definedName", ExcelPackage.schemaMain);
            top.AppendChild(elem);
            elem.SetAttribute("name", name.Name);
            elem.SetAttribute("localSheetId", name.LocalSheetId.ToString());
            if (name.IsNameHidden) elem.SetAttribute("hidden", "1");
            if (!string.IsNullOrEmpty(name.NameComment)) elem.SetAttribute("comment", name.NameComment);
            SetNameElement(name, elem);
          }
        }
      }
      catch (Exception ex)
      {
        throw new Exception("Internal error updating named ranges ",ex);
      }
    }

    private void SetNameElement(ExcelNamedRange name, XmlElement elem)
    {
      if (name.IsName)
      {
        if (string.IsNullOrEmpty(name.NameFormula))
        {
          if ((name.NameValue.GetType().IsPrimitive || name.NameValue is double || name.NameValue is decimal))
          {
            elem.InnerText = Convert.ToDouble(name.NameValue, CultureInfo.InvariantCulture).ToString("g15", CultureInfo.InvariantCulture); 
          }
          else if (name.NameValue is DateTime)
          {
            elem.InnerText = ((DateTime)name.NameValue).ToOADate().ToString(CultureInfo.InvariantCulture);
          }
          else
          {
            elem.InnerText = "\"" + name.NameValue.ToString() + "\"";
          }                                
        }
        else
        {
          elem.InnerText = name.NameFormula;
        }
      }
      else
      {
                elem.InnerText = name.FullAddressAbsolute;
      }
    }
    /// <summary>
    /// Is their any names in the workbook or in the sheets.
    /// </summary>
    /// <returns>?</returns>
    private bool ExistsNames()
    {
      if (_names.Count == 0)
      {
        foreach (ExcelWorksheet ws in Worksheets)
        {
          if(ws.Names.Count>0)
          {
            return true;
          }
        }
      }
      else
      {
        return true;
      }
      return false;
    }        
    #endregion

    #endregion
    internal bool ExistsTableName(string Name)
    {
      foreach (var ws in Worksheets)
      {
        if(ws.Tables._tableNames.ContainsKey(Name))
        {
          return true;
        }
      }
      return false;
    }
    internal bool ExistsPivotTableName(string Name)
    {
      foreach (var ws in Worksheets)
      {
        if (ws.PivotTables._pivotTableNames.ContainsKey(Name))
        {
          return true;
        }
      }
      return false;
    }
    internal void AddPivotTable(string cacheID, Uri defUri)
    {
      CreateNode("d:pivotCaches");

      XmlElement item = WorkbookXml.CreateElement("pivotCache", ExcelPackage.schemaMain);
      item.SetAttribute("cacheId", cacheID);
      var rel = Part.CreateRelationship(PackUriHelper.ResolvePartUri(WorkbookUri, defUri), TargetMode.Internal, ExcelPackage.schemaRelationships + "/pivotCacheDefinition");
      item.SetAttribute("id", ExcelPackage.schemaRelationships, rel.Id);

      var pivotCaches = WorkbookXml.SelectSingleNode("//d:pivotCaches", NameSpaceManager);
      pivotCaches.AppendChild(item);
    }
    internal List<string> _externalReferences = new List<string>();
    internal void GetExternalReferences()
    {
      XmlNodeList nl = WorkbookXml.SelectNodes("//d:externalReferences/d:externalReference", NameSpaceManager);
      if (nl != null)
      {
        foreach (XmlElement elem in nl)
        {
          string rID = elem.GetAttribute("r:id");
          PackageRelationship rel = Part.GetRelationship(rID);
          var part = _package.Package.GetPart(PackUriHelper.ResolvePartUri(rel.SourceUri, rel.TargetUri));
          XmlDocument xmlExtRef = new XmlDocument();
                    LoadXmlSafe(xmlExtRef, part.GetStream()); 

          XmlElement book=xmlExtRef.SelectSingleNode("//d:externalBook", NameSpaceManager) as XmlElement;
          if(book!=null)
          {
            string rId_ExtRef = book.GetAttribute("r:id");
            var rel_extRef = part.GetRelationship(rId_ExtRef);
            if (rel_extRef != null)
            {
              _externalReferences.Add(rel_extRef.TargetUri.OriginalString);
            }

          }
        }
      }
    }
    } // end Workbook
}