The following code works fine from a .NET Core app running on a PC. The code loads an excel file and reads it using the NPOI library.
public void ReadExcel()
{
DataTable dtTable = new DataTable();
List<string> rowList = new List<string>();
ISheet sheet;
using (var stream = new FileStream("Test.xlsx", FileMode.Open))
{
stream.Position = 0;
XSSFWorkbook xssWorkbook = new XSSFWorkbook(stream);
sheet = xssWorkbook.GetSheetAt(0);
IRow headerRow = sheet.GetRow(0);
int cellCount = headerRow.LastCellNum;
for (int j = 0; j < cellCount; j++)
{
ICell cell = headerRow.GetCell(j);
if (cell == null || string.IsNullOrWhiteSpace(cell.ToString())) continue;
{
dtTable.Columns.Add(cell.ToString());
}
}
for (int i = (sheet.FirstRowNum + 1); i <= sheet.LastRowNum; i++)
{
IRow row = sheet.GetRow(i);
if (row == null) continue;
if (row.Cells.All(d => d.CellType == CellType.Blank)) continue;
for (int j = row.FirstCellNum; j < cellCount; j++)
{
if (row.GetCell(j) != null)
{
if (!string.IsNullOrEmpty(row.GetCell(j).ToString()) && !string.IsNullOrWhiteSpace(row.GetCell(j).ToString()))
{
rowList.Add(row.GetCell(j).ToString());
}
}
}
if (rowList.Count > 0)
dtTable.Rows.Add(rowList.ToArray());
rowList.Clear();
}
}
return JsonConvert.SerializeObject(dtTable);
}
I want to use this code in my Blazor app to be able to read an Excel file from a browser. I can use the InputFile component to get the file:
<InputFile OnChange="GetFile"/>
The question is how to get the the uploaded file as a stream that I can pass to the ReadExcel function? So it should be something like this:
public async Task GetFile(InputFileChangeEventArgs e) //get excel file
{
stream = e.File.OpenReadStream(); //need a stream here that ReadExcel() can use!
ReadExcel();
}
If I use the above stream in the ReadExcel function instead of the one it has, the code doesnt work. What is the correct way of forming this stream so that ReadExcel can use that instead of the one it has now?
Thanks,
Amjad.
I think the major problem is that a ReadStream is not Seekable (CanSeek == false).
You can copy it to MemoryStream but do keep an eye on the size limits.
public async Task GetFile(InputFileChangeEventArgs e) //get excel file
{
var stream1 = e.File.OpenReadStream(); //need a stream here that ReadExcel() can use!
var stream2 = new MemoryStream();
await stream1.CopyToAsync(stream2);
stream1.Close();
ReadExcel(stream2);
}
I have an excel sheet with three column (Name, Gender, Email, Salary), I want to write a console application using NOPI library to select all male data with highest salary
I use this code to read file from xl
using System;
using System.IO;
using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
private static void procExcel(string fileName, string schoolPicDir){
try
{
IWorkbook workbook;
FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
if (fileName.IndexOf(".xlsx") > 0)
workbook = new XSSFWorkbook(fs);
else if (fileName.IndexOf(".xls") > 0)
workbook = new HSSFWorkbook(fs);
//First sheet
ISheet sheet = workbook.GetSheetAt(0);
if (sheet != null)
{
int rowCount = sheet.LastRowNum; // This may not be valid row count.
// If first row is table head, i starts from 1
for (int i = 1; i <= rowCount; i++)
{
IRow curRow = sheet.GetRow(i);
// Works for consecutive data. Use continue otherwise
if (curRow == null)
{
// Valid row count
rowCount = i - 1;
break;
}
// Get data from the 4th column (4th cell of each row)
var cellValue = curRow.GetCell(3).StringCellValue.Trim();
Console.WriteLine(cellValue);
}
}
}
catch(Exception e)
{
Console.WriteLine(e.Message);
}
}
I'm a french student in engineering school.
I have a work to do in my company (yes I work too).
I already developped an application that take xlsx file in input, I use NPOI library.
But now I need to take csv in input file, I tried several things without success.
I just need to convert a csv file as XSSFworkbook and sheet.
I'm newbie but I really want to improve my competences with c#.
Thanks for your help.
I've found on Github a sample that could help you:
class Program
{
static void Main(string[] args)
{
string csvDocument = #"FL_insurance_sample.csv";
var lines = ReadCsv(csvDocument, delimiter: ',');
ConvertWithNPOI("NPOI.xlsx", "NPOI", lines);
}
private static bool ConvertWithNPOI(string excelFileName, string worksheetName, IEnumerable<string[]> csvLines)
{
if (csvLines == null || csvLines.Count() == 0)
{
return (false);
}
int rowCount = 0;
int colCount = 0;
IWorkbook workbook = new XSSFWorkbook();
ISheet worksheet = workbook.CreateSheet(worksheetName);
foreach (var line in csvLines)
{
IRow row = worksheet.CreateRow(rowCount);
colCount = 0;
foreach (var col in line)
{
row.CreateCell(colCount).SetCellValue(TypeConverter.TryConvert(col));
colCount++;
}
rowCount++;
}
using (FileStream fileWriter = File.Create(excelFileName))
{
workbook.Write(fileWriter);
fileWriter.Close();
}
worksheet = null;
workbook = null;
return true;
}
private static bool ConvertWithEPPlus(string csvFileName, string excelFileName, string worksheetName, char delimiter = ';')
{
bool firstRowIsHeader = false;
var format = new ExcelTextFormat();
format.Delimiter = delimiter;
format.EOL = "\r"; // DEFAULT IS "\r\n";
// format.TextQualifier = '"';
using (ExcelPackage package = new ExcelPackage(new FileInfo(excelFileName)))
{
ExcelWorksheet worksheet = package.Workbook.Worksheets.Add(worksheetName);
worksheet.Cells["A1"].LoadFromText(new FileInfo(csvFileName), format, OfficeOpenXml.Table.TableStyles.Medium27, firstRowIsHeader);
package.Save();
}
return (true);
}
private static IEnumerable<string[]> ReadCsv(string fileName, char delimiter = ';')
{
var lines = System.IO.File.ReadAllLines(fileName, Encoding.UTF8).Select(a => a.Split(delimiter));
return (lines);
}
}
original https://github.com/Leftyx/ConvertCsvToExcel/blob/master/ConvertCsvToExcel/Program.cs
My sample Code is below using the NPOI.dll. I can read the EXCEL File (i.e. Excel would be stored in the system like D:/Jamal/Test.xls. Then the dll is easily reading the content, but I need to read the uploaded Excel file without storing it in any place before.The HTTPPOSTEDFILEBASE excelfile has the value for the Excel file but I need to know how to read it using NPOI dlls
public List<string> SendInvitesExcelFile1(List<String> CorrectMailIDs,
ListInvites Invites, HttpPostedFileBase excelfile)
{
List<string> mailids = new List<string>();
//string filename = (excelfile.FileName).ToString();
HSSFWorkbook hssfwb;
// using (FileStream file = new FileStream(#"D:\test.xls", FileMode.Open, FileAccess.Read))
using (FileStream file = new FileStream(excelFile.FileName, FileMode.Open, FileAccess.Read))
{
hssfwb = new HSSFWorkbook(file);
}
Sheet sheet = hssfwb.GetSheet("sheet1");
for (int row = 0; row <= sheet.LastRowNum; row++)
{
if (sheet.GetRow(row) != null) //null is when the row only contains empty cells
{
mailids.Add(sheet.GetRow(row).GetCell(0).ToString());
}
}
return mailids;
I came across the same problem and I solved it using Inpustream. I am pasting the code for your reference.
[HttpPost]
public DataTable PostValues(HttpPostedFileBase file)
{
ISheet sheet;
string filename = Path.GetFileName(Server.MapPath(file.FileName));
var fileExt = Path.GetExtension(filename);
if (fileExt == ".xls")
{
HSSFWorkbook hssfwb = new HSSFWorkbook(file.InputStream);
sheet = hssfwb.GetSheetAt(0);
}
else
{
XSSFWorkbook hssfwb = new XSSFWorkbook(file.InputStream);
sheet = hssfwb.GetSheetAt(0);
}
DataTable table = new DataTable();
IRow headerRow = sheet.GetRow(0);
int cellCount = headerRow.LastCellNum;
for (int i = headerRow.FirstCellNum; i < cellCount; i++)
{
DataColumn column = new DataColumn(headerRow.GetCell(i).StringCellValue);
table.Columns.Add(column);
}
int rowCount = sheet.LastRowNum;
for (int i = (sheet.FirstRowNum); i < sheet.LastRowNum; i++)
{
IRow row = sheet.GetRow(i);
DataRow dataRow = table.NewRow();
for (int j = row.FirstCellNum; j < cellCount; j++)
{
if (row.GetCell(j) != null)
{
dataRow[j] = row.GetCell(j).ToString();
}
}
table.Rows.Add(dataRow);
}
return table;
}
You can use a MemoryStream as well, so you should be able to get the byte array repsonse and open the spreadsheet. I'm unsure if the WorkbookFactory will detect the file type from the MemoryStream, so you may need to instruct the users to use the format that you require.
Here is how I use a MemoryStream to return a xls from a dot net core controller without ever storing it as a file.
IWorkbook wb = new HSSFWorkbook();
//Edit workbook object here
MemoryStream m = new MemoryStream();
wb.Write(m);
var byteArray = m.ToArray();
return new FileContentResult(byteArray, "application/vnd.ms-excel");
I know that there are different ways to read an Excel file:
Iterop
Oledb
Open Xml SDK
Compatibility is not a question because the program will be executed in a controlled environment.
My Requirement :
Read a file to a DataTable / CUstom Entities (I don't know how to make dynamic properties/fields to an object[column names will be variating in an Excel file])
Use DataTable/Custom Entities to perform some operations using its data.
Update DataTable with the results of the operations
Write it back to excel file.
Which would be simpler.
Also if possible advice me on custom Entities (adding properties/fields to an object dynamically)
Take a look at Linq-to-Excel. It's pretty neat.
var book = new LinqToExcel.ExcelQueryFactory(#"File.xlsx");
var query =
from row in book.Worksheet("Stock Entry")
let item = new
{
Code = row["Code"].Cast<string>(),
Supplier = row["Supplier"].Cast<string>(),
Ref = row["Ref"].Cast<string>(),
}
where item.Supplier == "Walmart"
select item;
It also allows for strongly-typed row access too.
I realize this question was asked nearly 7 years ago but it's still a top Google search result for certain keywords regarding importing excel data with C#, so I wanted to provide an alternative based on some recent tech developments.
Importing Excel data has become such a common task to my everyday duties, that I've streamlined the process and documented the method on my blog: best way to read excel file in c#.
I use NPOI because it can read/write Excel files without Microsoft Office installed and it doesn't use COM+ or any interops. That means it can work in the cloud!
But the real magic comes from pairing up with NPOI Mapper from Donny Tian because it allows me to map the Excel columns to properties in my C# classes without writing any code. It's beautiful.
Here is the basic idea:
I create a .net class that matches/maps the Excel columns I'm interested in:
class CustomExcelFormat
{
[Column("District")]
public int District { get; set; }
[Column("DM")]
public string FullName { get; set; }
[Column("Email Address")]
public string EmailAddress { get; set; }
[Column("Username")]
public string Username { get; set; }
public string FirstName
{
get
{
return Username.Split('.')[0];
}
}
public string LastName
{
get
{
return Username.Split('.')[1];
}
}
}
Notice, it allows me to map based on column name if I want to!
Then when I process the excel file all I need to do is something like this:
public void Execute(string localPath, int sheetIndex)
{
IWorkbook workbook;
using (FileStream file = new FileStream(localPath, FileMode.Open, FileAccess.Read))
{
workbook = WorkbookFactory.Create(file);
}
var importer = new Mapper(workbook);
var items = importer.Take<CustomExcelFormat>(sheetIndex);
foreach(var item in items)
{
var row = item.Value;
if (string.IsNullOrEmpty(row.EmailAddress))
continue;
UpdateUser(row);
}
DataContext.SaveChanges();
}
Now, admittedly, my code does not modify the Excel file itself. I am instead saving the data to a database using Entity Framework (that's why you see "UpdateUser" and "SaveChanges" in my example). But there is already a good discussion on SO about how to save/modify a file using NPOI.
Using OLE Query, it's quite simple (e.g. sheetName is Sheet1):
DataTable LoadWorksheetInDataTable(string fileName, string sheetName)
{
DataTable sheetData = new DataTable();
using (OleDbConnection conn = this.returnConnection(fileName))
{
conn.Open();
// retrieve the data using data adapter
OleDbDataAdapter sheetAdapter = new OleDbDataAdapter("select * from [" + sheetName + "$]", conn);
sheetAdapter.Fill(sheetData);
conn.Close();
}
return sheetData;
}
private OleDbConnection returnConnection(string fileName)
{
return new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + fileName + "; Jet OLEDB:Engine Type=5;Extended Properties=\"Excel 8.0;\"");
}
For newer Excel versions:
return new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + fileName + ";Extended Properties=Excel 12.0;");
You can also use Excel Data Reader an open source project on CodePlex. Its works really well to export data from Excel sheets.
The sample code given on the link specified:
FileStream stream = File.Open(filePath, FileMode.Open, FileAccess.Read);
//1. Reading from a binary Excel file ('97-2003 format; *.xls)
IExcelDataReader excelReader = ExcelReaderFactory.CreateBinaryReader(stream);
//...
//2. Reading from a OpenXml Excel file (2007 format; *.xlsx)
IExcelDataReader excelReader = ExcelReaderFactory.CreateOpenXmlReader(stream);
//...
//3. DataSet - The result of each spreadsheet will be created in the result.Tables
DataSet result = excelReader.AsDataSet();
//...
//4. DataSet - Create column names from first row
excelReader.IsFirstRowAsColumnNames = true;
DataSet result = excelReader.AsDataSet();
//5. Data Reader methods
while (excelReader.Read())
{
//excelReader.GetInt32(0);
}
//6. Free resources (IExcelDataReader is IDisposable)
excelReader.Close();
Reference: How do I import from Excel to a DataSet using Microsoft.Office.Interop.Excel?
Try to use this free way to this, https://freenetexcel.codeplex.com
Workbook workbook = new Workbook();
workbook.LoadFromFile(#"..\..\parts.xls",ExcelVersion.Version97to2003);
//Initialize worksheet
Worksheet sheet = workbook.Worksheets[0];
DataTable dataTable = sheet.ExportDataTable();
If you can restrict it to just (Open Office XML format) *.xlsx files, then probably the most popular library would be EPPLus.
Bonus is, there are no other dependencies. Just install using nuget:
Install-Package EPPlus
Try to use Aspose.cells library (not free, but trial is enough to read), it is quite good
Install-package Aspose.cells
There is sample code:
using Aspose.Cells;
using System;
namespace ExcelReader
{
class Program
{
static void Main(string[] args)
{
// Replace path for your file
readXLS(#"C:\MyExcelFile.xls"); // or "*.xlsx"
Console.ReadKey();
}
public static void readXLS(string PathToMyExcel)
{
//Open your template file.
Workbook wb = new Workbook(PathToMyExcel);
//Get the first worksheet.
Worksheet worksheet = wb.Worksheets[0];
//Get cells
Cells cells = worksheet.Cells;
// Get row and column count
int rowCount = cells.MaxDataRow;
int columnCount = cells.MaxDataColumn;
// Current cell value
string strCell = "";
Console.WriteLine(String.Format("rowCount={0}, columnCount={1}", rowCount, columnCount));
for (int row = 0; row <= rowCount; row++) // Numeration starts from 0 to MaxDataRow
{
for (int column = 0; column <= columnCount; column++) // Numeration starts from 0 to MaxDataColumn
{
strCell = "";
strCell = Convert.ToString(cells[row, column].Value);
if (String.IsNullOrEmpty(strCell))
{
continue;
}
else
{
// Do your staff here
Console.WriteLine(strCell);
}
}
}
}
}
}
Read from excel, modify and write back
/// <summary>
/// /Reads an excel file and converts it into dataset with each sheet as each table of the dataset
/// </summary>
/// <param name="filename"></param>
/// <param name="headers">If set to true the first row will be considered as headers</param>
/// <returns></returns>
public DataSet Import(string filename, bool headers = true)
{
var _xl = new Excel.Application();
var wb = _xl.Workbooks.Open(filename);
var sheets = wb.Sheets;
DataSet dataSet = null;
if (sheets != null && sheets.Count != 0)
{
dataSet = new DataSet();
foreach (var item in sheets)
{
var sheet = (Excel.Worksheet)item;
DataTable dt = null;
if (sheet != null)
{
dt = new DataTable();
var ColumnCount = ((Excel.Range)sheet.UsedRange.Rows[1, Type.Missing]).Columns.Count;
var rowCount = ((Excel.Range)sheet.UsedRange.Columns[1, Type.Missing]).Rows.Count;
for (int j = 0; j < ColumnCount; j++)
{
var cell = (Excel.Range)sheet.Cells[1, j + 1];
var column = new DataColumn(headers ? cell.Value : string.Empty);
dt.Columns.Add(column);
}
for (int i = 0; i < rowCount; i++)
{
var r = dt.NewRow();
for (int j = 0; j < ColumnCount; j++)
{
var cell = (Excel.Range)sheet.Cells[i + 1 + (headers ? 1 : 0), j + 1];
r[j] = cell.Value;
}
dt.Rows.Add(r);
}
}
dataSet.Tables.Add(dt);
}
}
_xl.Quit();
return dataSet;
}
public string Export(DataTable dt, bool headers = false)
{
var wb = _xl.Workbooks.Add();
var sheet = (Excel.Worksheet)wb.ActiveSheet;
//process columns
for (int i = 0; i < dt.Columns.Count; i++)
{
var col = dt.Columns[i];
//added columns to the top of sheet
var currentCell = (Excel.Range)sheet.Cells[1, i + 1];
currentCell.Value = col.ToString();
currentCell.Font.Bold = true;
//process rows
for (int j = 0; j < dt.Rows.Count; j++)
{
var row = dt.Rows[j];
//added rows to sheet
var cell = (Excel.Range)sheet.Cells[j + 1 + 1, i + 1];
cell.Value = row[i];
}
currentCell.EntireColumn.AutoFit();
}
var fileName="{somepath/somefile.xlsx}";
wb.SaveCopyAs(fileName);
_xl.Quit();
return fileName;
}
I used Office's NuGet Package: DocumentFormat.OpenXml and pieced together the code from that component's doc site.
With the below helper code, was similar in complexity to my other CSV file format parsing in that project...
public static async Task ImportXLSX(Stream stream, string sheetName) {
{
// This was necessary for my Blazor project, which used a BrowserFileStream object
MemoryStream ms = new MemoryStream();
await stream.CopyToAsync(ms);
using (var document = SpreadsheetDocument.Open(ms, false))
{
// Retrieve a reference to the workbook part.
WorkbookPart wbPart = document.WorkbookPart;
// Find the sheet with the supplied name, and then use that
// Sheet object to retrieve a reference to the first worksheet.
Sheet theSheet = wbPart?.Workbook.Descendants<Sheet>().Where(s => s?.Name == sheetName).FirstOrDefault();
// Throw an exception if there is no sheet.
if (theSheet == null)
{
throw new ArgumentException("sheetName");
}
WorksheetPart wsPart = (WorksheetPart)(wbPart.GetPartById(theSheet.Id));
// For shared strings, look up the value in the
// shared strings table.
var stringTable =
wbPart.GetPartsOfType<SharedStringTablePart>()
.FirstOrDefault();
// I needed to grab 4 cells from each row
// Starting at row 11, until the cell in column A is blank
int row = 11;
while (true) {
var accountNameCell = GetCell(wsPart, "A" + row.ToString());
var accountName = GetValue(accountNameCell, stringTable);
if (string.IsNullOrEmpty(accountName)) {
break;
}
var investmentNameCell = GetCell(wsPart, "B" + row.ToString());
var investmentName = GetValue(investmentNameCell, stringTable);
var symbolCell = GetCell(wsPart, "D" + row.ToString());
var symbol = GetValue(symbolCell, stringTable);
var marketValue = GetCell(wsPart, "J" + row.ToString()).InnerText;
// DO STUFF with data
row++;
}
}
}
private static string? GetValue(Cell cell, SharedStringTablePart stringTable) {
try {
return stringTable.SharedStringTable.ElementAt(int.Parse(cell.InnerText)).InnerText;
} catch (Exception) {
return null;
}
}
private static Cell GetCell(WorksheetPart wsPart, string cellReference) {
return wsPart.Worksheet.Descendants<Cell>().Where(c => c.CellReference.Value == cellReference)?.FirstOrDefault();
}