C#导入Excel数据（.NET Core3.1简单）

备注：
Demo项目创建的控制器为.NET Core3.1框架

1、控制台应用程序代码

using System;
using System.IO;

namespace Excel_Import
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("开始执行导入Excel程序");
            var filePath = @"D:\Test\TestExcel.xlsx";
            using (FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read))
            {
                byte[] bytes = new byte[fileStream.Length];
                fileStream.Read(bytes, 0, bytes.Length);
                fileStream.Close();
                // 把 byte[] 转换成 Stream
                Stream stream = new MemoryStream(bytes);
                var list = ExcelConvert.ToEntityStreamList<TestExcel>(stream, "TestExcel.xlsx");
                Console.WriteLine("开始遍历TestExcel");
                foreach (var item in list)
                {
                    Console.WriteLine($"姓名：{item.Name}；地址：{item.Address}");
                }
                Console.WriteLine("遍历TestExcel结束");
                Console.ReadLine();
            }
        }
    }

    /// 

    /// 测试Excel模型
    /// 
    public class TestExcel
    {
        /// 

        /// 姓名
        /// 
        [ExcelColumn("姓名")]
        public string Name { get; set; }

        /// 

        /// 分组
        /// 
        [ExcelColumn("地址")]
        public string Address { get; set; }
    }
}

2、帮助类代码

using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;
using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;

namespace Excel_Import
{
    /// 

    /// Excel帮助类
    /// 
    public class ExcelConvert
    {
        public static List<T> ToEntityStreamList<T>(Stream stream, string fileName, bool firstRow2Name = true) where T : new()
        {
            return ToEntityList<T>(stream, fileName);
        }

        /// 

        /// Excel转换为实体列表【普通】
        /// 
        /// 实体类
        /// 文件信息
        /// 第一行是否做为列名,默认为true
        /// 
        private static List<T> ToEntityList<T>(Stream stream, string fileName, bool firstRow2Name = true)
            where T : new()
        {
            // 加载Excel
            IWorkbook workbook;
            try
            {
                // 格式判断
                if (fileName.EndsWith(".xlsx"))
                {
                    workbook = new XSSFWorkbook(stream);
                }
                else
                {
                    workbook = new HSSFWorkbook(stream);
                }

                // 返回实体集
                var entities = new List<T>();

                // 读取第一页
                ISheet sheet = workbook.GetSheetAt(0);

                // 遍历所有行
                IEnumerator rows = sheet.GetRowEnumerator();

                // 反射实体判断实体行
                var columns = new List<EntityColumn>();

                #region 反射实体判断实体行对应Excel文件列
                // 名称行
                var excelFirstRow = new List<string>();
                if (firstRow2Name && rows.MoveNext())
                {
                    var row = (IRow)rows.Current;
                    for (int i = 0; i <= row.LastCellNum; i++)
                    {
                        ICell cell = row.GetCell(i);
                        if (cell == null) excelFirstRow.Add("");
                        else excelFirstRow.Add(cell.ToString());
                    }
                }

                // 反射
                PropertyInfo[] propertys = typeof(T).GetProperties();
                int propertyIndex = 0;
                foreach (PropertyInfo property in propertys)
                {
                    object[] excelColumns = property.GetCustomAttributes(typeof(ExcelColumnAttribute), true);
                    if (excelColumns.Length > 0)
                    {
                        string like = (excelColumns[0] as ExcelColumnAttribute).DisplayNameLike;
                        int excelIndex = (excelColumns[0] as ExcelColumnAttribute).ExcelIndex;
                        if (!string.IsNullOrEmpty(like))
                        {
                            for (int index = 0; index < excelFirstRow.Count; index++)
                            {
                                if (excelFirstRow[index].Contains(like))
                                {
                                    columns.Add(new EntityColumn { ColumnName = property.Name, ExcelIndex = index });
                                    break;
                                }
                            }
                        }
                        else if (excelIndex > -1)
                        {
                            columns.Add(new EntityColumn { ColumnName = property.Name, ExcelIndex = excelIndex });
                        }
                        else
                        {
                            columns.Add(new EntityColumn { ColumnName = property.Name, ExcelIndex = propertyIndex });
                        }
                    }
                    propertyIndex++;
                }
                #endregion

                // 遍历数据行
                while (rows.MoveNext())
                {
                    var row = (IRow)rows.Current;
                    var entity = new T();
                    PropertyInfo[] items = entity.GetType().GetProperties();
                    foreach (PropertyInfo property in items)
                    {
                        EntityColumn column = columns.FirstOrDefault(t => t.ColumnName == property.Name);
                        if (column != null)
                        {
                            ICell cell = row.GetCell(column.ExcelIndex);
                            if (cell == null)
                            //if (column.ExcelIndex - row.FirstCellNum >= row.Cells.Count || column.ExcelIndex - row.FirstCellNum < 0)
                            {
                                continue;
                            }

                            Object val = cell.ToString();

                            #region 数据类型转换
                            if (property.PropertyType == typeof(DateTime))
                            {
                                if (cell.CellType == CellType.Numeric)
                                {
                                    val = cell.DateCellValue;
                                }
                                else
                                {
                                    DateTime d;
                                    DateTime.TryParse(val.ToString(), out d);
                                    val = d;
                                }
                            }
                            else if (property.PropertyType == typeof(string))
                            {
                                val = val.ToString().Trim();
                            }
                            if (property.PropertyType == typeof(Int32))
                            {
                                if (cell.CellType == CellType.Numeric)
                                {
                                    val = (int)Math.Round(cell.NumericCellValue);
                                }
                                Int32 d;
                                Int32.TryParse(val.ToString(), out d);
                                val = d;
                            }
                            else if (property.PropertyType == typeof(UInt32))
                            {
                                if (cell.CellType == CellType.Numeric)
                                {
                                    val = Math.Round(cell.NumericCellValue);
                                }
                                UInt32 d;
                                UInt32.TryParse(val.ToString(), out d);
                                val = d;
                            }
                            else if (property.PropertyType == typeof(Int16))
                            {
                                if (cell.CellType == CellType.Numeric)
                                {
                                    val = Math.Round(cell.NumericCellValue);
                                }
                                Int16 d;
                                Int16.TryParse(val.ToString(), out d);
                                val = d;
                            }
                            else if (property.PropertyType == typeof(UInt16))
                            {
                                if (cell.CellType == CellType.Numeric)
                                {
                                    val = Math.Round(cell.NumericCellValue);
                                }
                                UInt16 d;
                                UInt16.TryParse(val.ToString(), out d);
                                val = d;
                            }
                            else if (property.PropertyType == typeof(float))
                            {
                                if (cell.CellType == CellType.Numeric)
                                {
                                    val = cell.NumericCellValue;
                                }
                                float d;
                                float.TryParse(val.ToString(), out d);
                                val = d;
                            }
                            else if (property.PropertyType == typeof(decimal))
                            {
                                if (cell.CellType == CellType.Numeric)
                                {
                                    val = cell.NumericCellValue;
                                }
                                decimal d;
                                decimal.TryParse(val.ToString(), out d);
                                val = d;
                            }
                            else if (property.PropertyType == typeof(double))
                            {
                                if (cell.CellType == CellType.Numeric)
                                {
                                    val = cell.NumericCellValue;
                                }
                                else
                                {
                                    double d;
                                    double.TryParse(val.ToString(), out d);
                                    val = d;
                                }
                            }
                            else if (property.PropertyType == typeof(byte))
                            {
                                if (cell.CellType == CellType.Numeric)
                                {
                                    val = (byte)Convert.ToInt32(cell.NumericCellValue);
                                }
                                else
                                {
                                    double d;
                                    double.TryParse(val.ToString(), out d);
                                    val = (byte)d;
                                }
                            }
                            #endregion

                            property.SetValue(entity, val, null);
                        }
                    }

                    entities.Add(entity);
                }

                // 返回结果
                return entities;
            }
            catch (Exception ex)
            {
            }
            return null;
        }
        private class EntityColumn
        {
            public string ColumnName { get; set; }

            public int ExcelIndex { get; set; }
        }
    }


    /// 

    /// Excel列属性【添加标签对象】
    /// 
    public class ExcelColumnAttribute : Attribute
    {
        public ExcelColumnAttribute()
        {
            ExcelIndex = -1;
        }

        public ExcelColumnAttribute(int excelIndex)
        {
            ExcelIndex = excelIndex;
        }

        public ExcelColumnAttribute(string displayNameLike)
        {
            DisplayNameLike = displayNameLike;
        }

        public int ExcelIndex { get; set; }

        public string DisplayNameLike { get; set; }
    }


}

结果：

Excel说明：
首行必须和定义类（TestExcel）中的标签名一致