It is possible to do this as I have actually just finished some code specifically to do this as part of a reporting project that I am working on where we have in-excess of 20K records that need to be pulled back and exported into excel.
I will pull out the code and stick it on github for you to look at.
I am actually using NPOI's excel processing package and then using my custom code I am able to process any List of classes dynamically into a dataset and then dump it into the worksheets.
I need to tidy up the code for you but I should have something ready for you this evening.
This code will work for both desktop and web apps.
To give you an idea my code has been able to process a dataset of over 30K relatively quickly. I have to resolve an issue with datasets over the limit of 65536 records first before it is ready for you.
The nice thing with this solution means it doesn't rely on excel being installed on the machine hosting the solution.
EDIT
I have loaded a project onto github here:
https://github.com/JellyMaster/ExcelHelper
but here is the main bit that does all the excel processing:
public static MemoryStream CreateExcelSheet(DataSet dataToProcess)
{
MemoryStream stream = new MemoryStream();
if (dataToProcess != null)
{
var excelworkbook = new HSSFWorkbook();
foreach (DataTable table in dataToProcess.Tables)
{
var worksheet = excelworkbook.CreateSheet();
var headerRow = worksheet.CreateRow(0);
foreach (DataColumn column in table.Columns)
{
headerRow.CreateCell(table.Columns.IndexOf(column)).SetCellValue(column.ColumnName);
}
//freeze top panel.
worksheet.CreateFreezePane(0, 1, 0, 1);
int rowNumber = 1;
foreach (DataRow row in table.Rows)
{
var sheetRow = worksheet.CreateRow(rowNumber++);
foreach (DataColumn column in table.Columns)
{
sheetRow.CreateCell(table.Columns.IndexOf(column)).SetCellValue(row[column].ToString());
}
}
}
excelworkbook.Write(stream);
}
return stream;
}
public static DataSet CreateDataSetFromExcel(Stream streamToProcess, string fileExtentison = "xlsx")
{
DataSet model = new DataSet();
if (streamToProcess != null)
{
if (fileExtentison == "xlsx")
{
XSSFWorkbook workbook = new XSSFWorkbook(streamToProcess);
model = ProcessXLSX(workbook);
}
else
{
HSSFWorkbook workbook = new HSSFWorkbook(streamToProcess);
model = ProcessXLSX(workbook);
}
}
return model;
}
private static DataSet ProcessXLSX(HSSFWorkbook workbook)
{
DataSet model = new DataSet();
for (int index = 0; index < workbook.NumberOfSheets; index++)
{
ISheet sheet = workbook.GetSheetAt(0);
if (sheet != null)
{
DataTable table = GenerateTableData(sheet);
model.Tables.Add(table);
}
}
return model;
}
private static DataTable GenerateTableData(ISheet sheet)
{
DataTable table = new DataTable(sheet.SheetName);
for (int rowIndex = 0; rowIndex <= sheet.LastRowNum; rowIndex++)
{
//we will assume the first row are the column names
IRow row = sheet.GetRow(rowIndex);
//a completely empty row of data so break out of the process.
if (row == null)
{
break;
}
if (rowIndex == 0)
{
for (int cellIndex = 0; cellIndex < row.LastCellNum; cellIndex++)
{
string value = row.GetCell(cellIndex).ToString();
if (string.IsNullOrEmpty(value))
{
break;
}
else
{
table.Columns.Add(new DataColumn(value));
}
}
}
else
{
//get the data and add to the collection
//now we know the number of columns to iterate through lets get the data and fill up the table.
DataRow datarow = table.NewRow();
object[] objectArray = new object[table.Columns.Count];
for (int columnIndex = 0; columnIndex < table.Columns.Count; columnIndex++)
{
try
{
ICell cell = row.GetCell(columnIndex);
if (cell != null)
{
objectArray[columnIndex] = cell.ToString();
}
else
{
objectArray[columnIndex] = string.Empty;
}
}
catch (Exception error)
{
Debug.WriteLine(error.Message);
Debug.WriteLine("Column Index" + columnIndex);
Debug.WriteLine("Row Index" + row.RowNum);
}
}
datarow.ItemArray = objectArray;
table.Rows.Add(datarow);
}
}
return table;
}
private static DataSet ProcessXLSX(XSSFWorkbook workbook)
{
DataSet model = new DataSet();
for (int index = 0; index < workbook.NumberOfSheets; index++)
{
ISheet sheet = workbook.GetSheetAt(index);
if (sheet != null)
{
DataTable table = GenerateTableData(sheet);
model.Tables.Add(table);
}
}
return model;
}
}
This does require the NPOI nuget package to be installed in your project.
Any questions give me a shout. The github project does a bit more but this is enough to get you going hopefully.
