NPOI：如何使用NPOI讀取文件

Question

我發現NPOI非常適合用C＃編寫Excel文件。 但我想在C＃中打開，閱讀和修改Excel文件。

我該怎麼做？

Answer 1

簡單的讀下面的例子：

using NPOI.HSSF.UserModel; 
using NPOI.SS.UserModel; 

//..... 

private void button1_Click(object sender, EventArgs e) 
{ 
    HSSFWorkbook hssfwb; 
    using (FileStream file = new FileStream(@"c:\test.xls", FileMode.Open, FileAccess.Read)) 
    { 
     hssfwb= new HSSFWorkbook(file); 
    } 

    ISheet sheet = hssfwb.GetSheet("Arkusz1"); 
    for (int row = 0; row <= sheet.LastRowNum; row++) 
    { 
     if (sheet.GetRow(row) != null) //null is when the row only contains empty cells 
     { 
      MessageBox.Show(string.Format("Row {0} = {1}", row, sheet.GetRow(row).GetCell(0).StringCellValue)); 
     } 
    } 
} 

順便說一句：在NPOI網站here在下載部分有例子包 - 的C＃示例一包。嘗試一下，如果你還沒有。 :)

Answer 2

因爲工廠方法會爲您檢測xls或xlsx，所以依靠Workbook工廠實例化工作簿對象可能會有所幫助。參考：http://apache-poi.1045710.n5.nabble.com/How-to-check-for-valid-excel-files-using-POI-without-checking-the-file-extension-td2341055.html

​​

如果你不知道該表的名字，但你一定索引（0爲主），你可以搶板這樣的：

ISheet sheet = workbook.GetSheetAt(sheetIndex); 

然後，您可以遍歷使用公認的答案提供的代碼從mj82

Answer 3

private DataTable GetDataTableFromExcel(String Path) 
    { 
     XSSFWorkbook wb; 
     XSSFSheet sh; 
     String Sheet_name; 

     using (var fs = new FileStream(Path, FileMode.Open, FileAccess.Read)) 
     { 
      wb = new XSSFWorkbook(fs); 

       Sheet_name= wb.GetSheetAt(0).SheetName; //get first sheet name 
     } 
     DataTable DT = new DataTable(); 
     DT.Rows.Clear(); 
     DT.Columns.Clear(); 

     // get sheet 
     sh = (XSSFSheet)wb.GetSheet(Sheet_name); 

     int i = 0; 
     while (sh.GetRow(i) != null) 
     { 
      // add neccessary columns 
      if (DT.Columns.Count < sh.GetRow(i).Cells.Count) 
      { 
       for (int j = 0; j < sh.GetRow(i).Cells.Count; j++) 
       { 
        DT.Columns.Add("", typeof(string)); 
       } 
      } 

      // add row 
      DT.Rows.Add(); 

      // write row value 
      for (int j = 0; j < sh.GetRow(i).Cells.Count; j++) 
      { 
       var cell = sh.GetRow(i).GetCell(j); 

       if (cell != null) 
       { 
        // TODO: you can add more cell types capatibility, e. g. formula 
        switch (cell.CellType) 
        { 
         case NPOI.SS.UserModel.CellType.Numeric: 
          DT.Rows[i][j] = sh.GetRow(i).GetCell(j).NumericCellValue; 
          //dataGridView1[j, i].Value = sh.GetRow(i).GetCell(j).NumericCellValue; 

          break; 
         case NPOI.SS.UserModel.CellType.String: 
          DT.Rows[i][j] = sh.GetRow(i).GetCell(j).StringCellValue; 

          break; 
        } 
       } 
      } 

      i++; 
     } 

     return DT; 
    } 

Answer 4

行，我覺得NPOI與Excel文件的工作非常有用的，這是我實現（註釋是西班牙語，對此感到抱歉）：

此方法打開Excel（xls或xlsx）文件並將其轉換爲DataTable。

 /// <summary>Abre un archivo de Excel (xls o xlsx) y lo convierte en un DataTable. 
    /// LA PRIMERA FILA DEBE CONTENER LOS NOMBRES DE LOS CAMPOS.</summary> 
    /// <param name="pRutaArchivo">Ruta completa del archivo a abrir.</param> 
    /// <param name="pHojaIndex">Número (basado en cero) de la hoja que se desea abrir. 0 es la primera hoja.</param> 
    private DataTable Excel_To_DataTable(string pRutaArchivo, int pHojaIndex) 
    { 
     // --------------------------------- // 
     /* REFERENCIAS: 
     * NPOI.dll 
     * NPOI.OOXML.dll 
     * NPOI.OpenXml4Net.dll */ 
     // --------------------------------- // 
     /* USING: 
     * using NPOI.SS.UserModel; 
     * using NPOI.HSSF.UserModel; 
     * using NPOI.XSSF.UserModel; */ 
     // AUTOR: Ing. Jhollman Chacon R. 2015 
     // --------------------------------- // 
     DataTable Tabla = null; 
     try 
     { 
      if (System.IO.File.Exists(pRutaArchivo)) 
      { 

       IWorkbook workbook = null; //IWorkbook determina si es xls o xlsx    
       ISheet worksheet = null; 
       string first_sheet_name = ""; 

       using (FileStream FS = new FileStream(pRutaArchivo, FileMode.Open, FileAccess.Read)) 
       { 
        workbook = WorkbookFactory.Create(FS);   //Abre tanto XLS como XLSX 
        worksheet = workbook.GetSheetAt(pHojaIndex); //Obtener Hoja por indice 
        first_sheet_name = worksheet.SheetName;   //Obtener el nombre de la Hoja 

        Tabla = new DataTable(first_sheet_name); 
        Tabla.Rows.Clear(); 
        Tabla.Columns.Clear(); 

        // Leer Fila por fila desde la primera 
        for (int rowIndex = 0; rowIndex <= worksheet.LastRowNum; rowIndex++) 
        { 
         DataRow NewReg = null; 
         IRow row = worksheet.GetRow(rowIndex); 
         IRow row2 = null; 
         IRow row3 = null; 

         if (rowIndex == 0) 
         { 
          row2 = worksheet.GetRow(rowIndex + 1); //Si es la Primera fila, obtengo tambien la segunda para saber el tipo de datos 
          row3 = worksheet.GetRow(rowIndex + 2); //Y la tercera tambien por las dudas 
         } 

         if (row != null) //null is when the row only contains empty cells 
         { 
          if (rowIndex > 0) NewReg = Tabla.NewRow(); 

          int colIndex = 0; 
          //Leer cada Columna de la fila 
          foreach (ICell cell in row.Cells) 
          { 
           object valorCell = null; 
           string cellType = ""; 
           string[] cellType2 = new string[2]; 

           if (rowIndex == 0) //Asumo que la primera fila contiene los titlos: 
           { 
            for (int i = 0; i < 2; i++) 
            { 
             ICell cell2 = null; 
             if (i == 0) { cell2 = row2.GetCell(cell.ColumnIndex); } 
             else { cell2 = row3.GetCell(cell.ColumnIndex); } 

             if (cell2 != null) 
             { 
              switch (cell2.CellType) 
              { 
               case CellType.Blank: break; 
               case CellType.Boolean: cellType2[i] = "System.Boolean"; break; 
               case CellType.String: cellType2[i] = "System.String"; break; 
               case CellType.Numeric: 
                if (HSSFDateUtil.IsCellDateFormatted(cell2)) { cellType2[i] = "System.DateTime"; } 
                else 
                { 
                 cellType2[i] = "System.Double"; //valorCell = cell2.NumericCellValue; 
                } 
                break; 

               case CellType.Formula:              
                bool continuar = true; 
                switch (cell2.CachedFormulaResultType) 
                { 
                 case CellType.Boolean: cellType2[i] = "System.Boolean"; break; 
                 case CellType.String: cellType2[i] = "System.String"; break; 
                 case CellType.Numeric: 
                  if (HSSFDateUtil.IsCellDateFormatted(cell2)) { cellType2[i] = "System.DateTime"; } 
                  else 
                  { 
                   try 
                   { 
                    //DETERMINAR SI ES BOOLEANO 
                    if (cell2.CellFormula == "TRUE()") { cellType2[i] = "System.Boolean"; continuar = false; } 
                    if (continuar && cell2.CellFormula == "FALSE()") { cellType2[i] = "System.Boolean"; continuar = false; } 
                    if (continuar) { cellType2[i] = "System.Double"; continuar = false; } 
                   } 
                   catch { } 
                  } break; 
                } 
                break; 
               default: 
                cellType2[i] = "System.String"; break; 
              } 
             } 
            } 

            //Resolver las diferencias de Tipos 
            if (cellType2[0] == cellType2[1]) { cellType = cellType2[0]; } 
            else 
            { 
             if (cellType2[0] == null) cellType = cellType2[1]; 
             if (cellType2[1] == null) cellType = cellType2[0]; 
             if (cellType == "") cellType = "System.String"; 
            } 

            //Obtener el nombre de la Columna 
            string colName = "Column_{0}"; 
            try { colName = cell.StringCellValue; } 
            catch { colName = string.Format(colName, colIndex); } 

            //Verificar que NO se repita el Nombre de la Columna 
            foreach (DataColumn col in Tabla.Columns) 
            { 
             if (col.ColumnName == colName) colName = string.Format("{0}_{1}", colName, colIndex); 
            } 

            //Agregar el campos de la tabla: 
            DataColumn codigo = new DataColumn(colName, System.Type.GetType(cellType)); 
            Tabla.Columns.Add(codigo); colIndex++; 
           } 
           else 
           { 
            //Las demas filas son registros: 
            switch (cell.CellType) 
            { 
             case CellType.Blank: valorCell = DBNull.Value; break; 
             case CellType.Boolean: valorCell = cell.BooleanCellValue; break; 
             case CellType.String: valorCell = cell.StringCellValue; break; 
             case CellType.Numeric: 
              if (HSSFDateUtil.IsCellDateFormatted(cell)) { valorCell = cell.DateCellValue; } 
              else { valorCell = cell.NumericCellValue; } break; 
             case CellType.Formula: 
              switch (cell.CachedFormulaResultType) 
              { 
               case CellType.Blank: valorCell = DBNull.Value; break; 
               case CellType.String: valorCell = cell.StringCellValue; break; 
               case CellType.Boolean: valorCell = cell.BooleanCellValue; break; 
               case CellType.Numeric: 
                if (HSSFDateUtil.IsCellDateFormatted(cell)) { valorCell = cell.DateCellValue; } 
                else { valorCell = cell.NumericCellValue; } 
                break; 
              } 
              break; 
             default: valorCell = cell.StringCellValue; break; 
            } 
            //Agregar el nuevo Registro 
            if (cell.ColumnIndex <= Tabla.Columns.Count - 1) NewReg[cell.ColumnIndex] = valorCell; 
           } 
          } 
         } 
         if (rowIndex > 0) Tabla.Rows.Add(NewReg); 
        } 
        Tabla.AcceptChanges(); 
       } 
      } 
      else 
      { 
       throw new Exception("ERROR 404: El archivo especificado NO existe."); 
      } 
     } 
     catch (Exception ex) 
     { 
      throw ex; 
     } 
     return Tabla; 
    } 

第二種方法執行oposite，節省了一個DataTable到Excel文件，是它可以是XLS或新的XLSX，您的choise！

 /// <summary>Convierte un DataTable en un archivo de Excel (xls o Xlsx) y lo guarda en disco.</summary> 
    /// <param name="pDatos">Datos de la Tabla a guardar. Usa el nombre de la tabla como nombre de la Hoja</param> 
    /// <param name="pFilePath">Ruta del archivo donde se guarda.</param> 
    private void DataTable_To_Excel(DataTable pDatos, string pFilePath) 
    { 
     try 
     { 
      if (pDatos != null && pDatos.Rows.Count > 0) 
      { 
       IWorkbook workbook = null; 
       ISheet worksheet = null; 

       using (FileStream stream = new FileStream(pFilePath, FileMode.Create, FileAccess.ReadWrite)) 
       { 
        string Ext = System.IO.Path.GetExtension(pFilePath); //<-Extension del archivo 
        switch (Ext.ToLower()) 
        { 
         case ".xls": 
          HSSFWorkbook workbookH = new HSSFWorkbook(); 
          NPOI.HPSF.DocumentSummaryInformation dsi = NPOI.HPSF.PropertySetFactory.CreateDocumentSummaryInformation(); 
          dsi.Company = "Cutcsa"; dsi.Manager = "Departamento Informatico"; 
          workbookH.DocumentSummaryInformation = dsi; 
          workbook = workbookH; 
          break; 

         case ".xlsx": workbook = new XSSFWorkbook(); break; 
        } 

        worksheet = workbook.CreateSheet(pDatos.TableName); //<-Usa el nombre de la tabla como nombre de la Hoja 

        //CREAR EN LA PRIMERA FILA LOS TITULOS DE LAS COLUMNAS 
        int iRow = 0; 
        if (pDatos.Columns.Count > 0) 
        { 
         int iCol = 0; 
         IRow fila = worksheet.CreateRow(iRow); 
         foreach (DataColumn columna in pDatos.Columns) 
         { 
          ICell cell = fila.CreateCell(iCol, CellType.String); 
          cell.SetCellValue(columna.ColumnName); 
          iCol++; 
         } 
         iRow++; 
        } 

        //FORMATOS PARA CIERTOS TIPOS DE DATOS 
        ICellStyle _doubleCellStyle = workbook.CreateCellStyle(); 
        _doubleCellStyle.DataFormat = workbook.CreateDataFormat().GetFormat("#,##0.###"); 

        ICellStyle _intCellStyle = workbook.CreateCellStyle(); 
        _intCellStyle.DataFormat = workbook.CreateDataFormat().GetFormat("#,##0"); 

        ICellStyle _boolCellStyle = workbook.CreateCellStyle(); 
        _boolCellStyle.DataFormat = workbook.CreateDataFormat().GetFormat("BOOLEAN"); 

        ICellStyle _dateCellStyle = workbook.CreateCellStyle(); 
        _dateCellStyle.DataFormat = workbook.CreateDataFormat().GetFormat("dd-MM-yyyy"); 

        ICellStyle _dateTimeCellStyle = workbook.CreateCellStyle(); 
        _dateTimeCellStyle.DataFormat = workbook.CreateDataFormat().GetFormat("dd-MM-yyyy HH:mm:ss"); 

        //AHORA CREAR UNA FILA POR CADA REGISTRO DE LA TABLA 
        foreach (DataRow row in pDatos.Rows) 
        { 
         IRow fila = worksheet.CreateRow(iRow); 
         int iCol = 0; 
         foreach (DataColumn column in pDatos.Columns) 
         { 
          ICell cell = null; //<-Representa la celda actual        
          object cellValue = row[iCol]; //<- El valor actual de la celda 

          switch (column.DataType.ToString()) 
          { 
           case "System.Boolean": 
            if (cellValue != DBNull.Value) 
            { 
             cell = fila.CreateCell(iCol, CellType.Boolean); 

             if (Convert.ToBoolean(cellValue)) { cell.SetCellFormula("TRUE()"); } 
             else { cell.SetCellFormula("FALSE()"); } 

             cell.CellStyle = _boolCellStyle; 
            } 
            break; 

           case "System.String": 
            if (cellValue != DBNull.Value) 
            { 
             cell = fila.CreateCell(iCol, CellType.String); 
             cell.SetCellValue(Convert.ToString(cellValue)); 
            } 
            break; 

           case "System.Int32": 
            if (cellValue != DBNull.Value) 
            { 
             cell = fila.CreateCell(iCol, CellType.Numeric); 
             cell.SetCellValue(Convert.ToInt32(cellValue)); 
             cell.CellStyle = _intCellStyle; 
            } 
            break; 
           case "System.Int64": 
            if (cellValue != DBNull.Value) 
            { 
             cell = fila.CreateCell(iCol, CellType.Numeric); 
             cell.SetCellValue(Convert.ToInt64(cellValue)); 
             cell.CellStyle = _intCellStyle; 
            } 
            break; 
           case "System.Decimal": 
            if (cellValue != DBNull.Value) 
            { 
             cell = fila.CreateCell(iCol, CellType.Numeric); 
             cell.SetCellValue(Convert.ToDouble(cellValue)); 
             cell.CellStyle = _doubleCellStyle; 
            } 
            break; 
           case "System.Double": 
            if (cellValue != DBNull.Value) 
            { 
             cell = fila.CreateCell(iCol, CellType.Numeric); 
             cell.SetCellValue(Convert.ToDouble(cellValue)); 
             cell.CellStyle = _doubleCellStyle; 
            } 
            break; 

           case "System.DateTime": 
            if (cellValue != DBNull.Value) 
            { 
             cell = fila.CreateCell(iCol, CellType.Numeric); 
             cell.SetCellValue(Convert.ToDateTime(cellValue)); 

             //Si No tiene valor de Hora, usar formato dd-MM-yyyy 
             DateTime cDate = Convert.ToDateTime(cellValue); 
             if (cDate != null && cDate.Hour > 0) { cell.CellStyle = _dateTimeCellStyle; } 
             else { cell.CellStyle = _dateCellStyle; } 
            } 
            break; 
           default: 
            break; 
          } 
          iCol++; 
         } 
         iRow++; 
        } 

        workbook.Write(stream); 
        stream.Close(); 
       } 
      } 
     } 
     catch (Exception ex) 
     { 
      throw ex; 
     } 
    } 

有了這個2種方法，你可以打開一個Excel文件，將其加載到一個DataTable，做修改並保存它放回一個Excel文件。

希望你們找到這個有用的。

Answer 5

private static ISheet GetFileStream(string fullFilePath) 
    { 
     var fileExtension = Path.GetExtension(fullFilePath); 
     string sheetName; 
     ISheet sheet = null; 
     switch (fileExtension) 
     { 
      case ".xlsx": 
       using (var fs = new FileStream(fullFilePath, FileMode.Open, FileAccess.Read)) 
       { 
        var wb = new XSSFWorkbook(fs); 
        sheetName = wb.GetSheetAt(0).SheetName; 
        sheet = (XSSFSheet) wb.GetSheet(sheetName); 
       } 
       break; 
      case ".xls": 
       using (var fs = new FileStream(fullFilePath, FileMode.Open, FileAccess.Read)) 
       { 
        var wb = new HSSFWorkbook(fs); 
        sheetName = wb.GetSheetAt(0).SheetName; 
        sheet = (HSSFSheet) wb.GetSheet(sheetName); 
       } 
       break; 
     } 
     return sheet; 
    } 

    private static DataTable GetRequestsDataFromExcel(string fullFilePath) 
    { 
     try 
     { 
      var sh = GetFileStream(fullFilePath); 
      var dtExcelTable = new DataTable(); 
      dtExcelTable.Rows.Clear(); 
      dtExcelTable.Columns.Clear(); 
      var headerRow = sh.GetRow(0); 
      int colCount = headerRow.LastCellNum; 
      for (var c = 0; c < colCount; c++) 
       dtExcelTable.Columns.Add(headerRow.GetCell(c).ToString()); 
      var i = 1; 
      var currentRow = sh.GetRow(i); 
      while (currentRow != null) 
      { 
       var dr = dtExcelTable.NewRow(); 
       for (var j = 0; j < currentRow.Cells.Count; j++) 
       { 
        var cell = currentRow.GetCell(j); 

        if (cell != null) 
         switch (cell.CellType) 
         { 
          case CellType.Numeric: 
           dr[j] = DateUtil.IsCellDateFormatted(cell) 
            ? cell.DateCellValue.ToString(CultureInfo.InvariantCulture) 
            : cell.NumericCellValue.ToString(CultureInfo.InvariantCulture); 
           break; 
          case CellType.String: 
           dr[j] = cell.StringCellValue; 
           break; 
          case CellType.Blank: 
           dr[j] = string.Empty; 
           break; 
         } 
       } 
       dtExcelTable.Rows.Add(dr); 
       i++; 
       currentRow = sh.GetRow(i); 
      } 
      return dtExcelTable; 
     } 
     catch (Exception e) 
     { 
      throw; 
     } 
    }