[Experimental] Add ToDataTable and ToDataSet feature

main/HSSF/UserModel/HSSFSheet.cs

@@ -37,6 +37,7 @@ namespace NPOI.HSSF.UserModel
     using NPOI.HSSF.UserModel.helpers;
 
     using SixLabors.Fonts;
+    using System.Data;
 
     /// <summary>
     /// High level representation of a worksheet.
@@ -3391,6 +3392,11 @@ IEnumerator<IRow> IEnumerable<IRow>.GetEnumerator()
             return rows.Values.GetEnumerator();
         }
 
+        public DataTable ToDataTable(bool firstRowAsHeader = false, bool showCalculatedValue = false)
+        {
+            return SheetUtil.ToDataTable(this, firstRowAsHeader, showCalculatedValue);
+        }
+
         public NCellRange Cells
         {
             get

main/HSSF/UserModel/HSSFWorkbook.cs

@@ -17,14 +17,6 @@ limitations Under the License.
 
 namespace NPOI.HSSF.UserModel
 {
-
-    using System;
-    using System.Collections;
-    using System.Collections.Generic;
-    using System.Globalization;
-    using System.IO;
-    using System.Security.Cryptography;
-    using System.Text;
     using NPOI.DDF;
     using NPOI.HPSF;
     using NPOI.HSSF.Model;
@@ -38,6 +30,14 @@ namespace NPOI.HSSF.UserModel
     using NPOI.SS.UserModel;
     using NPOI.SS.Util;
     using NPOI.Util;
+    using System;
+    using System.Collections;
+    using System.Collections.Generic;
+    using System.Data;
+    using System.Globalization;
+    using System.IO;
+    using System.Security.Cryptography;
+    using System.Text;
 
 
     /// <summary>
@@ -2499,6 +2499,11 @@ public bool IsDate1904()
             return Workbook.IsUsing1904DateWindowing;
         }
 
+        public DataSet ToDataSet(bool firstRowAsHeader = false, bool showCalculatedValue = false)
+        {
+            return WorkbookUtil.ToDataSet(this, firstRowAsHeader, showCalculatedValue);
+        }
+
         public void Dispose()
         {
             this.Close();

main/SS/UserModel/Sheet.cs

@@ -26,6 +26,7 @@ namespace NPOI.SS.UserModel
     using NPOI.SS.Util;
     using System.Collections;
     using NPOI.Util;
+    using System.Data;
 
     /// <summary>
     /// Indicate the position of the margin. One of left, right, top and bottom.
@@ -933,5 +934,13 @@ bool Autobreaks
 
         NCellRange Cells { get; }
         NRowRange Rows { get; }
+
+        /// <summary>
+        ///  Convert a sheet to a DataTable. Note that merged cells are not supported
+        /// </summary>
+        /// <param name="firstRowAsHeader">whether first row is column header</param>
+        /// <param name="showCalculatedValue">whether to show evaluated value of a formula in the cell</param>
+        /// <returns></returns>
+        DataTable ToDataTable(bool firstRowAsHeader = false, bool showCalculatedValue = false);
     }
 }

main/SS/UserModel/Workbook.cs

@@ -17,12 +17,13 @@ limitations under the License.
 
 namespace NPOI.SS.UserModel
 {
+    using NPOI.SS.Formula.UDF;
+    using NPOI.Util;
     using System;
     using System.Collections;
-    using System.IO;
-    using NPOI.SS.Formula.UDF;
     using System.Collections.Generic;
-    using NPOI.Util;
+    using System.Data;
+    using System.IO;
 
     /// <summary>
     /// High level interface of a Excel workbook.  This is the first object most users 
@@ -445,5 +446,7 @@ public interface IWorkbook : ICloseable, IDisposable
         /// <return>the index of the added ole object, i.e. the storage id</return>
         /// <exception cref="IOException">if the object can't be embedded</exception>
         int AddOlePackage(byte[] oleData, String label, String fileName, String command);
+
+        DataSet ToDataSet(bool firstRowAsHeader = false, bool showCalculatedValue = false);
     }
 }

main/SS/Util/SheetUtil.cs

@@ -17,14 +17,15 @@ limitations under the License.
 
 namespace NPOI.SS.Util
 {
-    using System;
-
+    using NPOI.HSSF.UserModel;
     using NPOI.SS.UserModel;
+    using SixLabors.Fonts;
+    using System;
     using System.Collections.Concurrent;
     using System.Collections.Generic;
-    using SixLabors.Fonts;
-    using System.Linq;
+    using System.Data;
     using System.Globalization;
+    using System.Linq;
 
     /**
      * Helper methods for when working with Usermodel sheets
@@ -913,6 +914,108 @@ public static ICell GetCellWithMerges(ISheet sheet, int rowIx, int colIx)
             //  live within any merged regions
             return null;
         }
+        /// <summary>
+        /// Convert a sheet to a DataTable. Note that merged cells are not supported
+        /// </summary>
+        /// <param name="sheet">original sheet</param>
+        /// <param name="firstRowAsHeader">whether first row is column header</param>
+        /// <param name="showCalculatedFormulaValue">whether to show evaluated value of a formula in the cell</param>
+        /// <returns></returns>
+        public static DataTable ToDataTable(ISheet sheet, bool firstRowAsHeader, bool showCalculatedFormulaValue)
+        {
+            DataTable dt = new DataTable(sheet.SheetName);
+
+            HSSFDataFormatter formatter = new HSSFDataFormatter();
+            var formulaEvaluator=sheet.Workbook.GetCreationHelper().CreateFormulaEvaluator();
+            for(int i = 0; i <= sheet.LastRowNum; i++)
+            {
+                var row=sheet.GetRow(i);
+                if(row == null)
+                {
+                    continue;
+                }
+                if(i == 0) //don't support merged cell so far
+                {
+                    if(firstRowAsHeader)
+                    {
+                        for(int j = 0; j < row.LastCellNum; j++)
+                        {
+                            var c = row.GetCell(j);
+                            dt.Columns.Add(c == null ? "" : formatter.FormatCellValue(c));
+                        }
+                        continue;
+                    }
+                }
 
+                DataRow dr = null!;
+                for(int j = 0; j < row.LastCellNum; j++)
+                {
+                    if(j == 0)
+                    {
+                        for(int k = dt.Columns.Count; k < row.LastCellNum; k++)
+                        {
+                            dt.Columns.Add("Column " + k);
+                        }
+                        dr = dt.NewRow();
+                    }
+                    var c = row.GetCell(j);
+                    if(c == null)
+                    {
+                        dr[j] = "";
+                        continue;
+                    }
+                    switch(c.CellType)
+                    {
+                        case CellType.Numeric:
+                            dr[j] =  c.NumericCellValue;
+                            break;
+                        case CellType.String:
+                            dr[j] = formatter.FormatCellValue(c);
+                            break;
+                        case CellType.Blank:
+                            dr[j] = "";
+                            break;
+                        case CellType.Boolean:
+                            dr[j] = c.BooleanCellValue;
+                            break;
+                        case CellType.Formula:
+                            if(showCalculatedFormulaValue)
+                            {
+                                var cellValue = formulaEvaluator.Evaluate(c);
+                                switch(cellValue.CellType)
+                                {
+                                    case CellType.Numeric:
+                                        dr[j] = cellValue.NumberValue;
+                                        break;
+                                    case CellType.String:
+                                        dr[j] = cellValue.StringValue;
+                                        break;
+                                    case CellType.Boolean:
+                                        dr[j] = cellValue.BooleanValue;
+                                        break;
+                                    case CellType.Error:
+                                        if(c.ErrorCellValue== FormulaError.NULL.Code)
+                                            dr[j] = "#NULL!";
+                                        else if(c.ErrorCellValue == FormulaError.DIV0.Code)
+                                            dr[j] = "#DIV/0!";
+                                        else if(c.ErrorCellValue == FormulaError.NUM.Code)
+                                            dr[j] = "#NUM!";
+                                        else if(c.ErrorCellValue == FormulaError.NAME.Code)
+                                            dr[j] = "#NAME!";
+                                        break;
+                                    case CellType.Blank:
+                                        dr[j] = "";
+                                        break;
+                                }
+                            }
+                            else
+                                dr[j] = c.CellFormula;
+                            break;
+                    }
+                }
+                dt.Rows.Add(dr);
+            }
+            return dt;
+        }
     }
 }

main/SS/Util/WorkbookUtil.cs

@@ -1,6 +1,7 @@
+using NPOI.SS.UserModel;
 using System;
+using System.Data;
 using System.Text;
-using NPOI.SS.UserModel;
 
 namespace NPOI.SS.Util
 {
@@ -206,6 +207,17 @@ public static int GetNextActiveSheetDueToSheetHiding(IWorkbook wb, int sheetIx)
                 return sheetIx;
             }
         }
+        public static DataSet ToDataSet(IWorkbook workbook, bool firstRowAsHeader, bool showCalculatedFormulaValue = false)
+        {
+            DataSet ds = new DataSet();
+            for(int i = 0; i < workbook.NumberOfSheets; i++)
+            {
+                var sheet=workbook.GetSheetAt(0);
+                var dt=sheet.ToDataTable(firstRowAsHeader, showCalculatedFormulaValue);
+                ds.Tables.Add(dt);
+            }
+            return ds;
+        }
     }
 
 }

ooxml/XSSF/Streaming/SXSSFSheet.cs

@@ -16,18 +16,19 @@ limitations under the License.
 ==================================================================== */
 
 using NPOI.HSSF.Util;
+using NPOI.OpenXmlFormats.Spreadsheet;
+using NPOI.SS;
+using NPOI.SS.UserModel;
+using NPOI.SS.Util;
+using NPOI.Util;
+using NPOI.XSSF.UserModel;
 using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
+using System.Data;
 using System.IO;
 using System.Linq;
-using NPOI.SS;
-using NPOI.SS.UserModel;
-using NPOI.SS.Util;
-using NPOI.Util;
-using NPOI.XSSF.UserModel;
-using NPOI.OpenXmlFormats.Spreadsheet;
 
 namespace NPOI.XSSF.Streaming
 {
@@ -1678,5 +1679,9 @@ public NRowRange Rows
                 return new NRowRange(this, 0, this.Workbook.SpreadsheetVersion.MaxRows);
             }
         }
+        public DataTable ToDataTable(bool firstRowAsHeader = false, bool showCalculatedValue = false)
+        {
+            return SheetUtil.ToDataTable(this, firstRowAsHeader, showCalculatedValue);
+        }
     }
 }

ooxml/XSSF/Streaming/SXSSFWorkbook.cs

@@ -15,20 +15,20 @@ the License.  You may obtain a copy of the License at
    limitations under the License.
 ==================================================================== */
 
-using System;
-using System.Collections;
-using System.Collections.Generic;
-using System.ComponentModel;
-using System.IO;
-using System.Text;
 using ICSharpCode.SharpZipLib.Zip;
-using NPOI.OpenXml4Net.Util;
 using NPOI.SS;
 using NPOI.SS.Formula.UDF;
 using NPOI.SS.UserModel;
+using NPOI.SS.Util;
 using NPOI.Util;
 using NPOI.XSSF.Model;
 using NPOI.XSSF.UserModel;
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Data;
+using System.IO;
+using System.Text;
 
 namespace NPOI.XSSF.Streaming
 {
@@ -997,6 +997,11 @@ public bool IsDate1904()
             return XssfWorkbook.IsDate1904();
         }
 
+        public DataSet ToDataSet(bool firstRowAsHeader = false, bool showCalculatedValue = false)
+        {
+            return WorkbookUtil.ToDataSet(this, firstRowAsHeader, showCalculatedValue);
+        }
+
         void IDisposable.Dispose()
         {
             this.Dispose();

ooxml/XSSF/UserModel/XSSFSheet.cs

@@ -41,6 +41,7 @@ limitations under the License.
 using ST_EditAs = NPOI.OpenXmlFormats.Dml.Spreadsheet.ST_EditAs;
 using System.Xml.Linq;
 using System.Diagnostics;
+using System.Data;
 
 namespace NPOI.XSSF.UserModel
 {
@@ -6626,6 +6627,11 @@ internal void OnSheetDelete() {
             }
         }
 
+        public DataTable ToDataTable(bool firstRowAsHeader = false, bool showCalculatedValue = false)
+        {
+            return SheetUtil.ToDataTable(this, firstRowAsHeader, showCalculatedValue);
+        }
+
         public XSSFHeaderFooterProperties HeaderFooterProperties
         {
             get

ooxml/XSSF/UserModel/XSSFWorkbook.cs

@@ -35,9 +35,9 @@ limitations under the License.
 using System.Collections;
 using NPOI.OpenXml4Net.Exceptions;
 using NPOI.SS;
-using System.Globalization;
 using System.Linq;
 using NPOI.POIFS.FileSystem;
+using System.Data;
 
 namespace NPOI.XSSF.UserModel
 {
@@ -2718,6 +2718,11 @@ public void Dispose()
         {
             this.Close();
         }
+
+        public DataSet ToDataSet(bool firstRowAsHeader = false, bool showCalculatedValue = false)
+        {
+            return WorkbookUtil.ToDataSet(this, firstRowAsHeader, showCalculatedValue);
+        }
     }
 }