[Excel] OpenXml import and export

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();

                //Page Create sheet 
                Sheet sheet = new new Sheet () 
                { 
                    // page associated WorksheetPart 
                    Id = spreadsheetDocument.WorkbookPart.GetIdOfPart (worksheetPart), 
                    SheetId = UInt32Value.FromUInt32 (( uint ) + S . 1 ), 
                    the Name = tname 
                }; 
                sheets.Append (sheet); 

                #region create sheet row 
                row row; 
                uint rowIndex = . 1 ;
                 // add header 
                row = new 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;
                //Find sheet by sheet page name 
                Sheet sheet = wbPart 
                    .Workbook 
                    .Descendants <Sheet> () 
                    .Where (S => == s.Name sheetName) 
                    .FirstOrDefault (); 

                IF (sheet == null ) 
                { 
                    the throw  new new ArgumentException The ( " Could not find " + sheetName + " sheet page " ); 
                } 

                // get shared Excel table 
                SharedStringTablePart sharedStringTablePart = wbPart
                    .GetPartsOfType <SharedStringTablePart> () 
                    .FirstOrDefault (); 
                SharedStringTable sharedStringTable = null ;
                 IF (sharedStringTablePart =! Null ) 
                    sharedStringTable = sharedStringTablePart.SharedStringTable;
                 #region Construction DataTable // add talbe columns, the number of columns returned 
                Func <Row, int > addTabColumn = (R & lt) => 
                { // iterate cell the foreach (the cell C in r.Elements <the 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>()) 
                { 
                    // build table column 
                    IF (r.RowIndex == . 1 ) 
                    { 
                        addTabColumn (R & lt); 
                        Continue ; 
                    } 
                    // build table row 
                    addTabRow (R & lt); 
                } 

            } 
            return dt; 
        } 

        ///  <Summary> 
        / // get a cell value
         ///  </ 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 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> (the DataTable dt) WHERE T: new new () 
        { 
            // definition of a set of 
            List <T> TS = new new List <T> ();
             // get the type of the model
            Type = type typeof (T);
            // define a temporary variable 
            String TempName = "" ;
             // iterate through all the data rows in datatable 
            the foreach (the DataRow DR in dt.Rows) 
            { 
                T T = new new T ();
                 // get the public properties model 
                PropertyInfo [] = the propertys t.GetType () GetProperties ();.
                 // iterate through all attributes 
                the foreach (PI PropertyInfo in the propertys) 
                { 
                    // this attribute is assigned to a temporary variable 
                    TempName = pi.Name;
                     // check the column contains datatable
                     IF (dt.Columns.Contains (TempName)) 
                    { 
                        // determines whether the attribute has the setter, it means that what is our physical layer {get; set;} If we have a set of entity method, you can assign it shows! 
                        IF (! pi.CanWrite) Continue ; 
                        { 
                            // Value   
                            Object value = DR [TempName];
                             IF (! = value DBNull.Value) 
                                pi.SetValue (T, value, null ); 
                        } 
                    } 
                } 
                // objects to generic collection
                 ts.Add (T); 
            } 
            return TS;

        }

    }
}