private static T ReadFromExcel<T>(string path, bool hasHeader = true)
        {
            using (var excelPack = new ExcelPackage())
            {
                //Load excel stream
                using (var stream = File.OpenRead(path))
                {
                    excelPack.Load(stream);
                }

                //Lets Deal with first worksheet.(You may iterate here if dealing with multiple sheets)
                var ws = excelPack.Workbook.Worksheets[0];

                //Get all details as DataTable -because Datatable make life easy :)
                DataTable excelasTable = new DataTable();
                foreach (var firstRowCell in ws.Cells[1, 1, 1, ws.Dimension.End.Column])
                {
                    //Get colummn details
                    if (!string.IsNullOrEmpty(firstRowCell.Text))
                    {
                        string firstColumn = string.Format("Column {0}", firstRowCell.Start.Column);
                        excelasTable.Columns.Add(hasHeader ? firstRowCell.Text : firstColumn);
                    }
                }
                var startRow = hasHeader ? 2 : 1;
                //Get row details
                for (int rowNum = startRow; rowNum <= ws.Dimension.End.Row; rowNum++)
                {
                    var wsRow = ws.Cells[rowNum, 1, rowNum, excelasTable.Columns.Count];
                    DataRow row = excelasTable.Rows.Add();
                    foreach (var cell in wsRow)
                    {
                        row[cell.Start.Column - 1] = cell.Text;
                    }
                }
               //Get everything as generics and let end user decides on casting to required type
                var generatedType = JsonConvert.DeserializeObject<T>(JsonConvert.SerializeObject(excelasTable));
                return (T)Convert.ChangeType(generatedType, typeof(T));
            }
        }

string strJSON = JsonConvert.SerializeObject(excelasTable)

List<UserDetails> userDetails = ReadFromExcel<List<UserDetails>>(@"C:\Users\TestDataRead.xlsx");

private static void WriteToExcel(string path)
        {
            //Let use below test data for writing it to excel
            List<UserDetails> persons = new List<UserDetails>()
            {
                new UserDetails() {ID="9999", Name="ABCD", City ="City1", Country="USA"},
                new UserDetails() {ID="8888", Name="PQRS", City ="City2", Country="INDIA"},
                new UserDetails() {ID="7777", Name="XYZZ", City ="City3", Country="CHINA"},
                new UserDetails() {ID="6666", Name="LMNO", City ="City4", Country="UK"},
           };

            // let's convert our object data to Datatable for a simplified logic.
            // Datatable is the easiest way to deal with complex datatypes for easy reading and formatting. 
            DataTable table = (DataTable)JsonConvert.DeserializeObject(JsonConvert.SerializeObject(persons), (typeof(DataTable)));
            FileInfo filePath = new FileInfo(path);
            using (var excelPack = new ExcelPackage(filePath))
            {
                var ws = excelPack.Workbook.Worksheets.Add("WriteTest");
                ws.Cells.LoadFromDataTable(table, true, OfficeOpenXml.Table.TableStyles.Light8);
                excelPack.Save();
            }
        }

static string ReadExcelasJSON()
        {
            try
            {
                DataTable dtTable = new DataTable();
                //Lets open the existing excel file and read through its content . Open the excel using openxml sdk
                using (SpreadsheetDocument doc = SpreadsheetDocument.Open("testdata2.xlsx", false))
                {
                    //create the object for workbook part  
                    WorkbookPart workbookPart = doc.WorkbookPart;
                    Sheets thesheetcollection = workbookPart.Workbook.GetFirstChild<Sheets>();

                    //using for each loop to get the sheet from the sheetcollection  
                    foreach (Sheet thesheet in thesheetcollection.OfType<Sheet>())
                    {
                        //statement to get the worksheet object by using the sheet id  
                        Worksheet theWorksheet = ((WorksheetPart)workbookPart.GetPartById(thesheet.Id)).Worksheet;

                        SheetData thesheetdata = theWorksheet.GetFirstChild<SheetData>();

                      

                        for (int rCnt = 0; rCnt < thesheetdata.ChildElements.Count(); rCnt++)
                        {
                            List<string> rowList = new List<string>();
                            for (int rCnt1 = 0; rCnt1
                                < thesheetdata.ElementAt(rCnt).ChildElements.Count(); rCnt1++)
                            {

                                Cell thecurrentcell = (Cell)thesheetdata.ElementAt(rCnt).ChildElements.ElementAt(rCnt1);
                                //statement to take the integer value  
                                string currentcellvalue = string.Empty;
                                if (thecurrentcell.DataType != null)
                                {
                                    if (thecurrentcell.DataType == CellValues.SharedString)
                                    {
                                        int id;
                                        if (Int32.TryParse(thecurrentcell.InnerText, out id))
                                        {
                                            SharedStringItem item = workbookPart.SharedStringTablePart.SharedStringTable.Elements<SharedStringItem>().ElementAt(id);
                                            if (item.Text != null)
                                            {
                                                //first row will provide the column name.
                                                if (rCnt == 0)
                                                {
                                                    dtTable.Columns.Add(item.Text.Text);
                                                }
                                                else
                                                {
                                                    rowList.Add(item.Text.Text);
                                                }
                                            }
                                            else if (item.InnerText != null)
                                            {
                                                currentcellvalue = item.InnerText;
                                            }
                                            else if (item.InnerXml != null)
                                            {
                                                currentcellvalue = item.InnerXml;
                                            }
                                        }
                                    }
                                }
                                else
                                {
                                    if (rCnt != 0)//reserved for column values
                                    {
                                        rowList.Add(thecurrentcell.InnerText);
                                    }
                                }
                            }
                            if (rCnt != 0)//reserved for column values
                                dtTable.Rows.Add(rowList.ToArray());

                        }

                    }

                    return JsonConvert.SerializeObject(dtTable);
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
                throw;
            }
        }

[
  {
    "ID": "1002",
    "Name": "ABCD",
    "City": "city",
    "Country": "USA"
  },
  {
    "ID": "1003",
    "Name": "PQRS",
    "City": "City",
    "Country": "UK"
  },
  {
    "ID": "1004",
    "Name": "ZYZZ",
    "City": "city3",
    "Country": "China"
  },
  {
    "ID": "1005",
    "Name": "LNMO",
    "City": "city4",
    "Country": "India"
  }
]

[
  {
    "ID": "1002",
    "Name": "ABCD",
    "City": "",
    "Country": "USA"
  },
  {
    "ID": "1003",
    "Name": "PQRS",
    "City": "City",
    "Country": "UK"
  },
  {
    "ID": "1004",
    "Name": "ZYZZ",
    "City": "city3",
    "Country": "China"
  },
  {
    "ID": "1005",
    "Name": "LNMO",
    "City": "city4",
    "Country": "India"
  }
]