Create New XLS with C#

Excel.Application objApp;
      Excel._Workbook objBook;
 
      private void button1_Click(object sender, System.EventArgs e)
      {
         Excel.Workbooks objBooks;
         Excel.Sheets objSheets;
         Excel._Worksheet objSheet;
         Excel.Range range;
 
         try
         {
            // Instantiate Excel and start a new workbook.
            objApp = new Excel.Application();
            objBooks = objApp.Workbooks;
            objBook = objBooks.Add( Missing.Value );
            objSheets = objBook.Worksheets;
            objSheet = (Excel._Worksheet)objSheets.get_Item(1);
 
            //Get the range where the starting cell has the address
            //m_sStartingCell and its dimensions are m_iNumRows x m_iNumCols.
            range = objSheet.get_Range("A1", Missing.Value);
            range = range.get_Resize(5, 5);
 
            if (this.FillWithStrings.Checked == false)
            {
               //Create an array.
               double[,] saRet = new double[5, 5];
 
               //Fill the array.
               for (long iRow = 0; iRow < 5; iRow++)
               {
                  for (long iCol = 0; iCol < 5; iCol++)
                  {
                     //Put a counter in the cell.
                     saRet[iRow, iCol] = iRow * iCol;
                  }
               }
 
               //Set the range value to the array.
               range.set_Value(Missing.Value, saRet );
            }
 
            else
            {
               //Create an array.
               string[,] saRet = new string[5, 5];
 
               //Fill the array.
               for (long iRow = 0; iRow < 5; iRow++)
               {
                  for (long iCol = 0; iCol < 5; iCol++)
                  {
                     //Put the row and column address in the cell.
                     saRet[iRow, iCol] = iRow.ToString() + "|" + iCol.ToString();
                  }
               }
 
               //Set the range value to the array.
               range.set_Value(Missing.Value, saRet );
            }
 
            //Return control of Excel to the user.
            objApp.Visible = true;
            objApp.UserControl = true;
         }
         catch( Exception theException ) 
         {
            String errorMessage;
            errorMessage = "Error: ";
            errorMessage = String.Concat( errorMessage, theException.Message );
            errorMessage = String.Concat( errorMessage, " Line: " );
            errorMessage = String.Concat( errorMessage, theException.Source );
 
            MessageBox.Show( errorMessage, "Error" );
         }
      }