title: NPOI set Explicit Column Type Not working properly
body: <p>I'm using NPOI Excel Library to generate a Excel file, in that Excel file i'm explicitly define column type for Columns like Date,String etc.</p>
  
  <p>Im using the following code to achive this.</p>
  
  <pre><code>  var row = sheet.CreateRow(currentNPOIRowIndex++);
                      for (var colIndex = 0; colIndex &lt; exportData.Columns.Count; colIndex++)
                      {
                          ICell cell = null;
                           cell = row.CreateCell(colIndex);
                          if (exportData.Columns[colIndex].DataType == typeof(DateTime))
                          {
                              if (exportData.Rows[rowIndex][colIndex].ToString() != "")
                              {
                                  cell.SetCellValue((DateTime)exportData.Rows[rowIndex][colIndex]);
                                  cell.CellStyle = (NPOI.HSSF.UserModel.HSSFCellStyle)book.CreateCellStyle();
                                  cell.CellStyle.DataFormat = book.CreateDataFormat().GetFormat("yyyyMMdd HH:mm:ss");
                                  cell = null;
                              }
                              else
                                  cell.SetCellValue(exportData.Rows[rowIndex][colIndex].ToString());
                          }
                          else
                              cell.SetCellValue(exportData.Rows[rowIndex][colIndex].ToString());
                      }
                  }
  </code></pre>
  
  <p>The above code works fine for 42 rows i.e. it correctly set the Column Type,but after 42 rows Column Type doesn't apply.</p>
  
  <p>Any help will be highly appreciated.</p>