OpenXML sdk Modify a sheet in my Excel document -

i create empty template in excel. open template , edit document not know how change existing sheet. that's code:

 using (spreadsheetdocument xl = spreadsheetdocument.open(filename, true))  {  workbookpart wbp = xl.workbookpart;  workbookpart workbook = xl.workbookpart;  // worksheet required name.  // used match id required sheet data  // because sheet class , sheetdata class aren't  // linked each other directly.  sheet s = null;  if (wbp.workbook.sheets.elements().count(nm => nm.name == sheetname) == 0)  {  // no such sheet name  xl.close();  return;  }  else  {  s = (sheet)wbp.workbook.sheets.elements().where(nm => nm.name == sheetname).first();  } 
  
worksheetpart wsp = (worksheetpart)xl.workbookpart.getpartbyid(s.id.value);  worksheet worksheet = new worksheet();  sheetdata sd = new sheetdata();  //sheetdata sd = (sheetdata)wsp.worksheet.getfirstchild();  stylesheet stylesheet = workbook.workbookstylespart.stylesheet;  //sheetdata sheetdata = new sheetdata();  //build formatted header style  uint32value headerfontindex =  util.createfont(  stylesheet,  "arial",  10,  true,  system.drawing.color.red); 
  
//build formatted date style  uint32value datefontindex =  util.createfont(  stylesheet,  "arial",  8,  true,  system.drawing.color.black); 
  
//set background color style  uint32value headerfillindex =  util.createfill(  stylesheet,  system.drawing.color.black); 
  
//create cell style combining font/background  uint32value headerstyleindex =  util.createcellformat(  stylesheet,  headerfontindex,  headerfillindex,  null);  /*  * create set of basic cell styles specific formats...  * if controlling table can create styles need,  * set of code still intended generic.  */  _numberstyleid = util.createcellformat(stylesheet, null, null, uint32value.fromuint32(3));  _doublestyleid = util.createcellformat(stylesheet, null, null, uint32value.fromuint32(4));  _datestyleid = util.createcellformat(stylesheet, null, null, uint32value.fromuint32(14));  _textstyleid = util.createcellformat(stylesheet, headerfontindex, headerfillindex, null);  _percentagestyleid = util.createcellformat(stylesheet, null, null, uint32value.fromuint32(9)); 
  
util.addnumber(xl, sheetname, (uint32)3, "e", "27", _numberstyleid);  util.addnumber(xl, sheetname, (uint32)3, "f", "3.6", _doublestyleid);  util.addnumber(xl, sheetname, (uint32)5, "l", "5", _percentagestyleid);  util.addtext(xl, sheetname, (uint32)5, "m", "dario", _textstyleid);  util.adddate(xl, sheetname, (uint32)3, "j", datetime.now, _datestyleid);  util.addimage(xl, sheetname, imagepath, "smile", "smile", 30, 30);  util.mergecells(xl, sheetname, "d12", "f12");  //util.deletevaluecell(spreadsheet, sheetname, "f", (uint32)8); 
  
txtcelltext.text = util.getcellvalue(xl, sheetname, (uint32)5, "m"); 
  
double number = util.getcelldoublevalue(xl, sheetname, (uint32)3, "e");  double numberd = util.getcelldoublevalue(xl, sheetname, (uint32)3, "f");  datetime datee = util.getcelldatetimevalue(xl, sheetname, (uint32)3, "j"); 
  
//txtdoublecell.text = util.getcellvalue(spreadsheet, sheetname, (uint32)3, "p");  txtpercentualecell.text = util.getcellvalue(xl, sheetname, (uint32)5, "l"); 
  
string date = util.getcellvalue(xl, sheetname, (uint32)3, "j");  double dated = convert.todouble(date);  datetime datetime = datetime.fromoadate(dated);  txtdatecell.text = datetime.toshortdatestring(); 
  
//worksheet.append(sd);  /*  columns columns = new columns();  columns.append(util.createcolumndata(10, 10, 40)); 
  
worksheet.append(columns);  */  sheetprotection sheetprotection1 = new sheetprotection() { sheet = true, objects = true, scenarios = true, selectlockedcells = true, selectunlockedcells = true };  worksheet.append(sheetprotection1);  wsp.worksheet = worksheet;  wsp.worksheet.save(); 
  
xl.workbookpart.workbook.save();  xl.close();  

thanks!

update

i try doesn't work.i'm using yet method (getworksheetpart() ) want existing worksheet, edit , save new document modified.

 using (spreadsheetdocument xl = spreadsheetdocument.open(filename, true)) {      workbookpart wbp = xl.workbookpart;
   worksheetpart worksheetpart = util.getworksheetpart(wbp, sheetname);  sheetprotection sheetprotection1 = new sheetprotection() { sheet = true, objects = true, scenarios = true, selectlockedcells = true, selectunlockedcells = true };   worksheetpart.worksheet.append(sheetprotection1);  worksheetpart.worksheet.save(); </pre></code> 

i build document corrupt. why?

to existing worksheet edit use code part:

        public static worksheetpart getworksheetpart(workbookpart workbookpart, string sheetname)         {             string relid = workbookpart.workbook.descendants<sheet>()                                  .where(s => sheetname.equals(s.name))                                  .first()                                  .id;              return (worksheetpart)workbookpart.getpartbyid(relid);         } 

just make sure sheetname exists searching or exceptions. use reference worksheetpart perform edits want , @ end call worksheetpart.worksheet.save();

edit

the sheetprotection element needs inserted after sheetdata element. try line when appending: worksheetpart.worksheet.descendants<sheetdata>().first().insertafterself(sheetprotection1);