c# - Unique column header -

public class reportsummary {     public void createheader()     {         var header = new list<keyvaluepair<string, string>>         {             new keyvaluepair<string, string>("description", "summary role*"),             new keyvaluepair<string, string>("colname1" , "public"),             new keyvaluepair<string, string>("colname2" , "non public"),             new keyvaluepair<string, string>("colname3" , "public"),             new keyvaluepair<string, string>("colname4" , "non public"),             new keyvaluepair<string, string>("colname5" , "public"),             new keyvaluepair<string, string>("colname6" , "non public"),             new keyvaluepair<string, string>("colname7" , "public"),             new keyvaluepair<string, string>("colname8" , "non public"),             new keyvaluepair<string, string>("colname9" , "public"),             new keyvaluepair<string, string>("colname10" , "non public"),             new keyvaluepair<string, string>("colname11" , "public"),             new keyvaluepair<string, string>("colname12" , "non public")         };          (int index = 0; index < header.count; index++)         {              row[index] = header[index].value;         }         addrow(_currentrow, row, rowstyleindex);         }       void addrow(int rowindex, object[] cells, params int[] styleindexes)     {         if (cells != null)         {             (int columnindex = 0; columnindex < cells.length; columnindex++)             {                 int styleindex = 16;                 //if style idex defined, pass it, or else pass default style index 16, bold header white background                 if (styleindexes != null)                 {                     styleindex = styleindexes[columnindex];                 }                  addcell((uint)rowindex, columnindex + 1, cells[columnindex], styleindex);             }         }     } }` 

class excelprocessor :

public class excelprocessor2010 {     protected cell addcell(uint rowindex, int columnindex, object cellvalue, int styleindex)     {         //removing values greyed out cell , empty cell         if (string.isnullorempty(convert.tostring(cellvalue)) || styleindex == 33)         {             cellvalue = " ";         }          cell cell = addcell(rowindex, columnindex, cellvalue);         cell.styleindex = (uint)styleindex;         return cell;     }      protected cell addcell(uint rowindex, int columnindex, object cellvalue)     {         cell cell = null;         if (cellvalue != null)         {              string cellvalueasstring = cellvalue.tostring();             if (!string.isnullorempty(cellvalueasstring))             {                 cell = insertcellinworksheet(getcolumnname(columnindex), rowindex);                 if ((cellvalue bool || cellvalue bool?))                 {                     cell.datatype = cellvalues.boolean;                 }                 else if (cellvalue datetime || cellvalue datetime?)                 {                     cell.datatype = cellvalues.date;                 }                 else if (cellvalue string && !string.isnullorempty((string)cellvalue))                 {                     cell.datatype = cellvalues.sharedstring;                 }                 else if (cellvalue byte || cellvalue byte? ||                             cellvalue sbyte || cellvalue sbyte? ||                             cellvalue short || cellvalue short? ||                             cellvalue ushort || cellvalue ushort? ||                             cellvalue int || cellvalue int? ||                             cellvalue uint || cellvalue uint? ||                             cellvalue long || cellvalue long? ||                             cellvalue ulong || cellvalue ulong? ||                             cellvalue float || cellvalue float? ||                             cellvalue double || cellvalue double? ||                             cellvalue decimal || cellvalue decimal?                     )                 {                     cell.datatype = cellvalues.number;                 }                  if (cell.cellvalue == null)                 {                     cell.append(new cellvalue                                     {                                         text =                                             cell.datatype != cellvalues.sharedstring                                                 ? cellvalueasstring                                                 : insertsharedstringitem(cellvalueasstring)                                     });                 }                 else                 {                     cell.cellvalue.text = cellvalueasstring;                 }             }         }          return cell;     }      protected string insertsharedstringitem(string text)     {         // if part not contain sharedstringtable, create one.         if (sharedstringtablepart.sharedstringtable == null)         {             sharedstringtablepart.sharedstringtable = new sharedstringtable();         }          int = 0;          // iterate through items in sharedstringtable. if text exists, return index.         foreach (sharedstringitem item in sharedstringtablepart.sharedstringtable.elements<sharedstringitem>())         {             if (item.innertext == text)             {                 return i.tostring();             }              i++;         }          // text not exist in part. create sharedstringitem , return index.         sharedstringtablepart.sharedstringtable.appendchild(new sharedstringitem(new text(text)));         //sharedstringtablepart.sharedstringtable.save();          return i.tostring();     } } 

i generating excel file using openxml. trying create table in excel shown in image:

but changing column headers public/nonpublic public1, nonpublic2, public3, nonpublic4 etc... after research understood excel expecting unique column headers. it's happening when create excel using openxml. if create excel manually , set headers these works fine.

can me on this?