How to import all the Excel sheets to DataSet in C#

Question

I\'ve searched internet for this and couldn\'t really find a question like it. Everyone was looking for a way to import an individual sheet in the excel file but what I want

Answer 1

This might not be the best and the fastest one, but its another way (Edit- added elimination of blank cells):

    public static DataSet ReadWorkbook(string excelFileName, bool useFirstRowAsColumnName = false)
    {
        var excel = new Microsoft.Office.Interop.Excel.Application();
        var workBook = excel.Workbooks.Open(excelFileName, 0, true, 5, "", "", true, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "\t", false, false, 0, true, 1, 0);//MLHIDE
        try
        {
            System.Data.DataSet ds = new DataSet(excelFileName);
            foreach (var sheet0 in workBook.Worksheets)
            {
                var sheet = (Microsoft.Office.Interop.Excel.Worksheet)sheet0;
                try
                {
                    var dt = readSheet(sheet, useFirstRowAsColumnName);
                    if (dt != null)
                        ds.Tables.Add(dt);
                }
                finally
                {
                    releaseObject(sheet);
                }
            }
            return ds;
        }
        finally
        {
            workBook.Close(true, null, null);
            excel.Quit();

            releaseObject(workBook);
            releaseObject(excel);
        }
    }

    /// 

    /// Returns null for empty sheets or if sheet is not found.
    /// 
    public static DataTable ReadSheet(string excelFileName, string sheetName, bool useFirstRowAsColumnName = false)
    {
        var excel = new Microsoft.Office.Interop.Excel.Application();
        var workBook = excel.Workbooks.Open(excelFileName, 0, true, 5, "", "", true, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "\t", false, false, 0, true, 1, 0);//MLHIDE
        try
        {
            foreach (var sheet0 in workBook.Worksheets)
            {
                var sheet = (Microsoft.Office.Interop.Excel.Worksheet)sheet0;
                try
                {
                    if (sheet.Name.Equals_Wildcard(sheetName))
                    {
                        var dt = readSheet(sheet, useFirstRowAsColumnName);
                        if (dt != null)
                            return dt;
                    }
                }
                finally
                {
                    releaseObject(sheet);
                }
            }
            return null;
        }
        finally
        {
            workBook.Close(true, null, null);
            excel.Quit();

            releaseObject(workBook);
            releaseObject(excel);
        }
    }

    /// 

    /// Returns null for empty sheets
    /// 
private static DataTable readSheet(Microsoft.Office.Interop.Excel.Worksheet sheet, bool useFirstRowAsColumnName = false)
        {
            using (Dece.Common.BeginChangeCurrentCultureBlock_EN_us())
            {
                var range = sheet.UsedRange;
                try
                {
                    object[,] values = (object[,])range.Value2;
                    int rowCount = values.GetLength(0);
                    int colCount = values.GetLength(1);
                    int rowCount0 = rowCount;
                    int colCount0 = colCount;
                    #region find row-col count
                    {
                        bool ok = false;
                        for (int row = rowCount; row > 0; row--)
                            if (!ok)
                                for (int col = colCount; col > 0; col--)
                                {
                                    var val = values[row, col];
                                    if ((val != null) && (!System.Convert.ToString(val).IsNullOrEmpty()))
                                    {
                                        rowCount = row;
                                        ok = true;
                                        break;
                                    }
                                }
                            else
                                break;
                    }
                    {
                        bool ok = false;
                        for (int col = colCount; col > 0; col--)
                            if (!ok)
                                for (int row = rowCount; row > 0; row--)
                                {
                                    var val = values[row, col];
                                    if ((val != null) && (!System.Convert.ToString(val).IsNullOrEmpty()))
                                    {
                                        colCount = col;
                                        ok = true;
                                        break;
                                    }
                                }
                            else
                                break;
                    }
                    #endregion
                    if ((rowCount > 0) && (colCount > 0))
                    {  
                        var dt = new DataTable(sheet.Name);
                        dt.BeginLoadData();
                        try
                        {
                            for (int col = 1; col <= colCount; col++)
                                dt.Columns.Add_RenameIfRequired(useFirstRowAsColumnName ? values[1, col].ToString_NullProof() : col.ToString());
                            var arr = new object[colCount];
                            for (int row = useFirstRowAsColumnName ? 1 : 0; row < rowCount; row++)
                            {
                                for (int col = 1; col <= colCount; col++)
                                    arr[col - 1] = values[row + 1, col];
                                dt.Rows.Add(arr);
                            }
                        }
                        finally
                        {
                            dt.EndLoadData();
                        }
                        return dt;                        
                    }
                    else
                        return null;
                }
                finally
                {
                    releaseObject(range);
                }
            }
        }

    private static void releaseObject(object obj)
    {
        try
        {
            System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
            obj = null;
        }
        catch (Exception ex)
        {
            obj = null;
            throw new Exception("Unable to release the Object " + ex.ToString(), ex);//MLHIDE
        }
        finally
        {
            GC.Collect();
        }
    }