WeihanLi.Npoi Save Abandoned

NPOI Extensions, excel/csv importer/exporter for IEnumerable/DataTable, fluentapi(great flexibility)/attribute configuration

Project README



WeihanLi.Npoi Latest

Build Status

Azure Pipeline Build Status

Github Build Status

Travis Build Status


NPOI extensions based on target framework netstandard2.0/net6.0.

There're a lot of useful extensions for you, core features are as follows:

  • mapping a excel file data to a DataTable or List<TEntity>/IEnumerable<T>
  • export IEnumerable<TEntity> or DataTable data to Excel file or Excel file bytes or even write excel file stream to your stream
  • export IEnumerable<TEntity> or DataTable data to csv file or bytes.
  • custom configuration/mappings by Attribute or FluentAPI(inspired by FluentExcel)
  • great flexibility by fluent InputFormatter/OutputFormatter/ColumnInputFormatter/ColumnOutputFormatter/CellReader


  1. Export list/dataTable to Excel/csv

    var entities = new List<Entity>();
    entities.ToExcelFile(string excelPath);
    entities.ToExcelBytes(ExcelFormat excelFormat);
    entities.ToCsvFile(string csvPath);
  2. Read Excel/csv to List

    // read excel first sheet content to List<T>
    var entityList = ExcelHelper.ToEntityList<T>(string excelPath);
    // read excel first sheet content to IEnumerable<T>
    var entityList = ExcelHelper.ToEntities<T>(string excelPath);
    // read excel sheetIndex sheet content to a List<T>
    // you can custom header row index via sheet attribute or fluent api HasSheet
    var entityList1 = ExcelHelper.ToEntityList<T>(string excelPath, int sheetIndex);
    var entityList2 = CsvHelper.ToEntityList<T>(string csvPath);
    var entityList3 = CsvHelper.ToEntityList<T>(byte[] csvBytes);
  3. Read Excel/csv to DataTable

    // read excel to dataTable directly,by default read the first sheet content
    var dataTable = ExcelHelper.ToDataTable(string excelPath);
    // read excel workbook's sheetIndex sheet to dataTable directly
    var dataTableOfSheetIndex = ExcelHelper.ToDataTable(string excelPath, int sheetIndex);
    // read excel workbook's sheetIndex sheet to dataTable,custom headerRowIndex
    var dataTableOfSheetIndex = ExcelHelper.ToDataTable(string excelPath, int sheetIndex, int headerRowIndex);
    // read excel to dataTable use mapping relations and settings from typeof(T),by default read the first sheet content
    var dataTableT = ExcelHelper.ToDataTable<T>(string excelPath);
    // read csv file data to dataTable
    var dataTable1 = CsvHelper.ToDataTable(string csvFilePath);

More Api here: https://weihanli.github.io/WeihanLi.Npoi/docs/api/WeihanLi.Npoi.html

Define Custom Mapping and settings

  1. Attributes

    Add ColumnAttribute on the property of the entity which you used for export or import

    Add SheetAttribute on the entity which you used for export or import,you can set the StartRowIndex on your need(by default it is 1)

    for example:

    public class TestEntity
        public int PKID { get; set; }
        [Column("Bill Title")]
        public string BillTitle { get; set; }
        [Column("Bill Details")]
        public string BillDetails { get; set; }
        public string CreatedBy { get; set; }
        public DateTime CreatedTime { get; set; }
    public class TestEntity1
        public string Username { get; set; }
        [Column(IsIgnored = true)]
        public string PasswordHash { get; set; }
        public decimal Amount { get; set; } = 1000M;
        public string WechatOpenId { get; set; }
        public bool IsActive { get; set; }
  2. FluentApi (Recommended)

    You can use FluentApi for great flexibility

    for example:

    var setting = FluentSettings.For<TestEntity>();
    // ExcelSetting
        .HasTitle("WeihanLi.Npoi test")
        .HasDescription("WeihanLi.Npoi test")
        .HasSubject("WeihanLi.Npoi test");
    setting.HasSheetConfiguration(0, "SystemSettingsList", true);
    // setting.HasSheetConfiguration(1, "SystemSettingsList", 1, true);
    // setting.HasFilter(0, 1).HasFreezePane(0, 1, 2, 1);
    setting.Property(_ => _.SettingId)
    setting.Property(_ => _.SettingName)
    setting.Property(_ => _.DisplayName)
        .HasOutputFormatter((entity, displayName) => $"AAA_{entity.SettingName}_{displayName}")
        .HasInputFormatter((entity, originVal) => originVal.Split(new[] { '_' })[2])
    setting.Property(_ => _.SettingValue)
    setting.Property(_ => _.CreatedTime)
        .HasColumnFormatter("yyyy-MM-dd HH:mm:ss");
    setting.Property(_ => _.CreatedBy)
        .HasColumnInputFormatter(x => x += "_test")
    setting.Property(x => x.Enabled)
        .HasColumnInputFormatter(val => "Enabled".Equals(val))
        .HasColumnOutputFormatter(v => v ? "Enabled" : "Disabled");
        .HasOutputFormatter((entity, val) => $"HiddenProp_{entity.PKID}");
    setting.Property(_ => _.PKID).Ignored();
    setting.Property(_ => _.UpdatedBy).Ignored();
    setting.Property(_ => _.UpdatedTime).Ignored();


see some articles here: https://weihanli.github.io/WeihanLi.Npoi/docs/articles/intro.html

more usage:

Get a workbook
// load excel workbook from file
var workbook = LoadExcel(string excelPath);

// prepare a workbook accounting to excelPath
var workbook = PrepareWorkbook(string excelPath);

// prepare a workbook accounting to excelPath and custom excel settings
var workbook = PrepareWorkbook(string excelPath, ExcelSetting excelSetting);

// prepare a workbook whether *.xls file
var workbook = PrepareWorkbook(bool isXls);

// prepare a workbook whether *.xls file and custom excel setting
var workbook = PrepareWorkbook(bool isXlsx, ExcelSetting excelSetting);
Rich extensions
List<TEntity> ToEntityList<TEntity>([NotNull]this IWorkbook workbook)

DataTable ToDataTable([NotNull]this IWorkbook workbook)

ISheet ImportData<TEntity>([NotNull] this ISheet sheet, DataTable dataTable)

int ImportData<TEntity>([NotNull] this IWorkbook workbook, IEnumerable<TEntity> list,
            int sheetIndex)

int ImportData<TEntity>([NotNull] this ISheet sheet, IEnumerable<TEntity> list)

int ImportData<TEntity>([NotNull] this IWorkbook workbook, [NotNull] DataTable dataTable,
            int sheetIndex)

ToExcelFile<TEntity>([NotNull] this IEnumerable<TEntity> entityList,
            [NotNull] string excelPath)

int ToExcelStream<TEntity>([NotNull] this IEnumerable<TEntity> entityList,
            [NotNull] Stream stream)

byte[] ToExcelBytes<TEntity>([NotNull] this IEnumerable<TEntity> entityList)

int ToExcelFile([NotNull] this DataTable dataTable, [NotNull] string excelPath)

int ToExcelStream([NotNull] this DataTable dataTable, [NotNull] Stream stream)

byte[] ToExcelBytes([NotNull] this DataTable dataTable)

byte[] ToExcelBytes([NotNull] this IWorkbook workbook)

int WriteToFile([NotNull] this IWorkbook workbook, string filePath)

object GetCellValue([NotNull] this ICell cell, Type propertyType)

T GetCellValue<T>([NotNull] this ICell cell)

void SetCellValue([NotNull] this ICell cell, object value)

byte[] ToCsvBytes<TEntity>(this IEnumerable<TEntity> entities, bool includeHeader)

ToCsvFile<TEntity>(this IEnumerable<TEntity> entities, string filePath, bool includeHeader)

void ToCsvFile(this DataTable dt, string filePath, bool includeHeader)

byte[] ToCsvBytes(this DataTable dt, bool includeHeader)



  • Thanks for the contributors and users for this project
  • Thanks JetBrains for the open source ReSharper license


Contact me: [email protected]

Open Source Agenda is not affiliated with "WeihanLi.Npoi" Project. README Source: WeihanLi/WeihanLi.Npoi
Open Issues
Last Commit
5 months ago

Open Source Agenda Badge

Open Source Agenda Rating