Another day and another little tidbit on using NPOI. I was doing tool mock-up at work today when I ran across a need for a copy row function. After searching high and low, I realized NPOI does not currently offer this capability. After looking around (Google, NPOI and POI threads) I decided to create my own helper function. I’m sure there might be a few things I missed in my routine since the library is a bit new to me, but after testing this against a bunch of different scenarios I’m pretty confident this will work for 99% of my needs and maybe a high percent of yours as well.

Here is the function in all it’s glory, I thought about modify the NPOI source but since I’m not sure where it’s going I figured I’d just add this in my own little NPOI.CustomHelpers class that I can use with my NPOI project.

[sourcecode language=”csharp”]
/// <summary>
/// HSSFRow Copy Command
///
/// Description: Inserts a existing row into a new row, will automatically push down
/// any existing rows. Copy is done cell by cell and supports, and the
/// command tries to copy all properties available (style, merged cells, values, etc…)
/// </summary>
/// <param name="workbook">Workbook containing the worksheet that will be changed</param>
/// <param name="worksheet">WorkSheet containing rows to be copied</param>
/// <param name="sourceRowNum">Source Row Number</param>
/// <param name="destinationRowNum">Destination Row Number</param>
private void CopyRow(HSSFWorkbook workbook, HSSFSheet worksheet, int sourceRowNum, int destinationRowNum)
{
// Get the source / new row
HSSFRow newRow = worksheet.GetRow(destinationRowNum);
HSSFRow sourceRow = worksheet.GetRow(sourceRowNum);

// If the row exist in destination, push down all rows by 1 else create a new row
if (newRow != null)
{
worksheet.ShiftRows(destinationRowNum, worksheet.LastRowNum, 1);
}
else
{
newRow = worksheet.CreateRow(destinationRowNum);
}

// Loop through source columns to add to new row
for (int i = 0; i < sourceRow.LastCellNum; i++)
{
// Grab a copy of the old/new cell
HSSFCell oldCell = sourceRow.GetCell(i);
HSSFCell newCell = newRow.CreateCell(i);

// If the old cell is null jump to next cell
if (oldCell == null)
{
newCell = null;
continue;
}

// Copy style from old cell and apply to new cell
HSSFCellStyle newCellStyle = workbook.CreateCellStyle();
newCellStyle.CloneStyleFrom(oldCell.CellStyle); ;
newCell.CellStyle = newCellStyle;

// If there is a cell comment, copy
if (newCell.CellComment != null) newCell.CellComment = oldCell.CellComment;

// If there is a cell hyperlink, copy
if (oldCell.Hyperlink != null) newCell.Hyperlink = oldCell.Hyperlink;

// Set the cell data type
newCell.SetCellType(oldCell.CellType);

// Set the cell data value
switch (oldCell.CellType)
{
case HSSFCellType.BLANK:
newCell.SetCellValue(oldCell.StringCellValue);
break;
case HSSFCellType.BOOLEAN:
newCell.SetCellValue(oldCell.BooleanCellValue);
break;
case HSSFCellType.ERROR:
newCell.SetCellErrorValue(oldCell.ErrorCellValue);
break;
case HSSFCellType.FORMULA:
newCell.SetCellFormula(oldCell.CellFormula);
break;
case HSSFCellType.NUMERIC:
newCell.SetCellValue(oldCell.NumericCellValue);
break;
case HSSFCellType.STRING:
newCell.SetCellValue(oldCell.RichStringCellValue);
break;
case HSSFCellType.Unknown:
newCell.SetCellValue(oldCell.StringCellValue);
break;
}
}

// If there are are any merged regions in the source row, copy to new row
for (int i = 0; i < worksheet.NumMergedRegions; i++)
{
CellRangeAddress cellRangeAddress = worksheet.GetMergedRegion(i);
if (cellRangeAddress.FirstRow == sourceRow.RowNum)
{
CellRangeAddress newCellRangeAddress = new CellRangeAddress(newRow.RowNum,
(newRow.RowNum +
(cellRangeAddress.FirstRow –
cellRangeAddress.LastRow)),
cellRangeAddress.FirstColumn,
cellRangeAddress.LastColumn);
worksheet.AddMergedRegion(newCellRangeAddress);
}
}

}
[/sourcecode]

The code comments above should give you a good idea of what I’m doing, if something doesn’t make sense just ask. The key things I wanted to make sure got copied were; Cell Style, Cell Value, Cell Type, Merged Cell Settings. In the end I noticed a few other things that I thought I might use in the future, so I included them as well. Here is an example of how to call to CopyRow along with a snapshot of the end result.

[sourcecode language=”csharp”]
// Grab my NPOI workbook memorystream
HSSFWorkbook workbook = new HSSFWorkbook(memoryStream);

// Grab my test worksheet
HSSFSheet sheet = workbook.GetSheet("Sheet1");

// Copy Excel Row 1 to Excel Row 3
CopyRow(workbook, sheet, 0, 2);

// Copy Excel Row 2 to Excel Row 4
CopyRow(workbook, sheet, 1, 3);
[/sourcecode]

NPOI - Copy Row Helper Function Test Results