【OpenXml】excel 导入导出

using DocumentFormat.OpenXml;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Spreadsheet;
using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Reflection;
using System.Text;

namespace Tools
{
    /// <summary>
    /// 
    /// </summary>
    public class ExcelOpenXml
    {

        /*
         * excel 对象结构
         * SpreadsheetDocument
         *   》WorkbookPart
         *       》WorksheetPart
         *           》Worksheet
         *            》SheetData
         *       》WorksheetPart
         *          》Worksheet
         *                》SheetData1
         *       》Workbook
         *           》Sheets
         *                》Sheet
         */
        public static void Create(string filename, DataSet ds)
        {
            SpreadsheetDocument spreadsheetDocument = SpreadsheetDocument.Create(filename, SpreadsheetDocumentType.Workbook);

            WorkbookPart workbookpart = spreadsheetDocument.AddWorkbookPart();
            Workbook workbook = new Workbook();
            Sheets sheets = new Sheets();

            #region 创建多个 sheet 页

            //创建多个sheet
            for (int s = 0; s < ds.Tables.Count; s++)
            {
                DataTable dt = ds.Tables[s];
                var tname = dt.TableName;

                WorksheetPart worksheetPart = workbookpart.AddNewPart<WorksheetPart>();
                Worksheet worksheet = new Worksheet();
                SheetData sheetData = new SheetData();

                //创建 sheet 页
                Sheet sheet = new Sheet()
                {
                    //页面关联的 WorksheetPart
                    Id = spreadsheetDocument.WorkbookPart.GetIdOfPart(worksheetPart),
                    SheetId = UInt32Value.FromUInt32((uint)s + 1),
                    Name = tname
                };
                sheets.Append(sheet);

                #region 创建sheet 行
                Row row;
                uint rowIndex = 1;
                //添加表头
                row = new Row()
                {
                    RowIndex = UInt32Value.FromUInt32(rowIndex++)
                };
                sheetData.Append(row);
                for (int i = 0; i < dt.Columns.Count; i++)
                {
                    Cell newCell = new Cell();
                    newCell.CellValue = new CellValue(dt.Columns[i].ColumnName);
                    newCell.DataType = new EnumValue<CellValues>(CellValues.String);
                    row.Append(newCell);
                }
                //添加内容
                object val = null;
                for (int i = 0; i < dt.Rows.Count; i++)
                {
                    row = new Row()
                    {
                        RowIndex = UInt32Value.FromUInt32(rowIndex++)
                    };
                    sheetData.Append(row);

                    for (int j = 0; j < dt.Columns.Count; j++)
                    {
                        Cell newCell = new Cell();
                        val = dt.Rows[i][j];
                        newCell.CellValue = new CellValue(val.ToString());
                        newCell.DataType = new EnumValue<CellValues>(CellValues.String);

                        row.Append(newCell);
                    }

                }
                #endregion

                worksheet.Append(sheetData);
                worksheetPart.Worksheet = worksheet;
                worksheetPart.Worksheet.Save();
            }
            #endregion

            workbook.Append(sheets);
            workbookpart.Workbook = workbook;

            workbookpart.Workbook.Save();
            spreadsheetDocument.Close();
        }

        public static DataTable GetSheet(string filename, string sheetName)
        {
            DataTable dt = new DataTable();
            using (SpreadsheetDocument document = SpreadsheetDocument.Open(filename, false))
            {
                WorkbookPart wbPart = document.WorkbookPart;
                //通过sheet名查找 sheet页
                Sheet sheet = wbPart
                    .Workbook
                    .Descendants<Sheet>()
                    .Where(s => s.Name == sheetName)
                    .FirstOrDefault();

                if (sheet == null)
                {
                    throw new ArgumentException("未能找到" + sheetName + " sheet 页");
                }

                //获取Excel中共享表
                SharedStringTablePart sharedStringTablePart = wbPart
                    .GetPartsOfType<SharedStringTablePart>()
                    .FirstOrDefault();
                SharedStringTable sharedStringTable = null;
                if (sharedStringTablePart != null)
                    sharedStringTable = sharedStringTablePart.SharedStringTable;
                #region 构建datatable

                //添加talbe列,返回列数
                Func<Row, int> addTabColumn = (r) =>
                {
                    //遍历单元格
                    foreach (Cell c in r.Elements<Cell>())
                    {
                        dt.Columns.Add(GetCellVal(c, sharedStringTable));
                    }
                    return dt.Columns.Count;
                };
                //添加行
                Action<Row> addTabRow = (r) =>
                {
                    DataRow dr = dt.NewRow();
                    int colIndex = 0;
                    int colCount = dt.Columns.Count;
                    //遍历单元格
                    foreach (Cell c in r.Elements<Cell>())
                    {
                        if (colIndex >= colCount)
                            break;
                        dr[colIndex++] = GetCellVal(c, sharedStringTable);
                    }
                    dt.Rows.Add(dr);
                };
                #endregion


                //通过 sheet.id 查找 WorksheetPart 
                WorksheetPart worksheetPart
                    = wbPart.GetPartById(sheet.Id) as WorksheetPart;
                //查找 sheetdata
                SheetData sheetData = worksheetPart.Worksheet.Elements<SheetData>().First();

                //遍历行
                foreach (Row r in sheetData.Elements<Row>())
                {
                    //构建table列
                    if (r.RowIndex == 1)
                    {
                        addTabColumn(r);
                        continue;
                    }
                    //构建table行
                    addTabRow(r);
                }

            }
            return dt;
        }

        /// <summary>
        /// 获取单元格值
        /// </summary>
        /// <param name="cell"></param>
        /// <param name="sharedStringTable"></param>
        /// <returns></returns>
        static string GetCellVal(Cell cell, SharedStringTable sharedStringTable)
        {
            var val = cell.InnerText;

            if (cell.DataType != null)
            {
                switch (cell.DataType.Value)
                {
                    //从共享表中获取值
                    case CellValues.SharedString:
                        if (sharedStringTable != null)
                            val = sharedStringTable
                                .ElementAt(int.Parse(val))
                                .InnerText;
                        break;
                    default:
                        val = string.Empty;
                        break;
                }

            }
            return val;
        }

        public static DataSet ConvertToDataSet<T>(IList<T> list)
        {
            if (list == null || list.Count <= 0)
            {
                return null;
            }
            DataSet ds = new DataSet();
            DataTable dt = new DataTable(typeof(T).Name);
            DataColumn column;
            DataRow row;
            System.Reflection.PropertyInfo[] myPropertyInfo = typeof(T).GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance);
            foreach (T t in list)
            {
                if (t == null)
                {
                    continue;
                }
                row = dt.NewRow();
                for (int i = 0, j = myPropertyInfo.Length; i < j; i++)
                {
                    System.Reflection.PropertyInfo pi = myPropertyInfo[i];
                    string name = pi.Name;



                    if (dt.Columns[name] == null)
                    {
                        var type = pi.PropertyType;
                        if (type.IsGenericType && type.GetGenericTypeDefinition() == typeof(Nullable<>))
                        {
                            type = type.GetGenericArguments()[0];
                        }
                        column = new DataColumn(name, type);
                        dt.Columns.Add(column);
                    }
                    row[name] = pi.GetValue(t, null);
                }
                dt.Rows.Add(row);
            }
            ds.Tables.Add(dt);
            return ds;
        }
        public static List<T> ConvertToList<T>(DataTable dt) where T : new()
        {
            //定义集合
            List<T> ts = new List<T>();
            //获得此模型的类型
            Type type = typeof(T);
            //定义一个临时的变量
            string tempName = "";
            //遍历datatable中所有数据行
            foreach (DataRow dr in dt.Rows)
            {
                T t = new T();
                //获得此模型的公共属性
                PropertyInfo[] propertys = t.GetType().GetProperties();
                //遍历所有属性
                foreach (PropertyInfo pi in propertys)
                {
                    //将此属性赋值给临时变量
                    tempName = pi.Name;
                    //检查datatable是否包含此列
                    if (dt.Columns.Contains(tempName))
                    {
                        //判断此属性是否有setter，这个啥意思呢，就是我们的实体层的{get;set;}如果我们的实体有了set方法，就说明可以赋值！
                        if (!pi.CanWrite) continue;
                        {
                            //取值  
                            object value = dr[tempName];
                            if (value != DBNull.Value)
                                pi.SetValue(t, value, null);
                        }
                    }
                }
                //对象添加到泛型集合中
                ts.Add(t);
            }
            return ts;

        }

    }
}