create multiple excels with multiple sheet using ExcelLibrary in C#

Question

I want to export the data in multiple sheets with multiple excel files. As you can see in my image I want to generate sheets as ID changes and when ModalityId changes I want to create new excel.

I have made code like this for this concern:

List<string> lstFile = new List<string>();
if (dtAltTag != null && dtAltTag.Rows.Count > 0)
{
    string filePath = string.Empty;
    string fileName = "";

    Excel.Workbook workBook = new Excel.Workbook();
    var workSheet = new Excel.Worksheet(fileName);

    if (dtAltTag.Rows[0]["OldFormCode"] != null && dtAltTag.Rows[0]["OldFormCode"].ToString() != "")
    {
        fileName = dtAltTag.Rows[0]["OldFormCode"].ToString();
    }
    else
    {
        fileName = dtAltTag.Rows[0]["Code"].ToString();
    }
    workSheet.Name = fileName;
    AddValue(0, workSheet, dtAltTag); // function is used to add the value in the sheet
    workBook.Worksheets.Add(workSheet);

    //data working
    for (int i = 0; i < dtAltTag.Rows.Count; i++)
    {
        //for modality changes and first entery 
        //if (i == 0 || dtAltTag.Rows[i]["ModalityId"] != dtAltTag.Rows[i - 1]["ModalityId"])
        //{
        //if form changes then it should be in other sheet
        if (i != 0 && dtAltTag.Rows[i]["ID"].ToString() != dtAltTag.Rows[i - 1]["ID"].ToString())
        {
            if (dtAltTag.Rows[i]["OldFormCode"] != null && dtAltTag.Rows[i]["OldFormCode"].ToString() != "")
            {
                fileName = dtAltTag.Rows[i]["OldFormCode"].ToString();
            }
            else
            {
                fileName = dtAltTag.Rows[i]["Code"].ToString();
            }
            var workSheet1 = new Excel.Worksheet(fileName);

            AddValue(i, workSheet1, dtAltTag);
        }
        else
        {

        }
    }

    filePath = HostingEnvironment.MapPath(ConfigurationManager.AppSettings["ExcelFilesFilePath"]) + "Allitem";
    if (!File.Exists(filePath))
        Directory.CreateDirectory(filePath);
    filePath = filePath + "\\" + fileName + "_" + DateTime.Now.ToString("MM_dd_yyy_HH_mm_ss") + ".xls";
    workBook.Save(filePath);
    lstFile.Add(filePath);
}
return lstFile;

When the id is changed I append new header but after that, I want to continue export data till the id change can't detect how to do this? How can I get the current sheet where I continue adding the value in else case?

I hope you are cleared of what I am trying to do!

Thanks in advance!

Answer 1

With the reference of 'Rafalon' code , I made some change in my code and its working fine ! thank You!

My code is as below:

 var filePath = "";
            string fileName = "";

            if (dtAltTag.Rows[0]["OldFormCode"] != null && dtAltTag.Rows[0]["OldFormCode"].ToString() != "")
            {
                fileName = dtAltTag.Rows[0]["OldFormCode"].ToString();
            }
            else
            {
                fileName = dtAltTag.Rows[0]["Code"].ToString();
            }

            int Row = 0;
            var currentFile = new Excel.Workbook();
            var currentSheet = new Excel.Worksheet(fileName);
            currentFile.Worksheets.Add(currentSheet);

            List<string> lstFile = new List<string>();
            if (dtAltTag != null && dtAltTag.Rows.Count > 0)
            {


                for (int i = 0; i < dtAltTag.Rows.Count; i++)
                {

                    if (i == 0)
                    {
                        AddValue(i, currentSheet, dtAltTag, Row);
                    }
                    else
                    {
                        if (dtAltTag.Rows[i]["ModalityId"].ToString() != dtAltTag.Rows[i - 1]["ModalityId"].ToString())
                        {
                            filePath = HostingEnvironment.MapPath(ConfigurationManager.AppSettings["ExcelFilesFilePath"]) + "Allitem";
                            if (!File.Exists(filePath))
                                Directory.CreateDirectory(filePath);
                            filePath = filePath + "\\" + fileName + "_" + DateTime.Now.ToString("MM_dd_yyy_HH_mm_ss") + ".xls";
                            lstFile.Add(filePath);
                            currentFile.Save(filePath);
                            currentFile = new Excel.Workbook();

                        }
                        if (dtAltTag.Rows[i]["ID"].ToString() != dtAltTag.Rows[i - 1]["ID"].ToString())
                        {

                            if (dtAltTag.Rows[i]["OldFormCode"] != null && dtAltTag.Rows[i]["OldFormCode"].ToString() != "")
                            {
                                fileName = dtAltTag.Rows[i]["OldFormCode"].ToString();
                            }
                            else
                            {
                                fileName = dtAltTag.Rows[i]["Code"].ToString();
                            }
                            currentSheet = new Excel.Worksheet(fileName);
                            currentFile.Worksheets.Add(currentSheet);
                            Row = 0;

                        }

                        AddValue(i, currentSheet, dtAltTag, Row);


                    }
                    Row++;

                }


                filePath = HostingEnvironment.MapPath(ConfigurationManager.AppSettings["ExcelFilesFilePath"]) + "Allitem";
                if (!File.Exists(filePath))
                    Directory.CreateDirectory(filePath);
                filePath = filePath + "\\" + fileName + "_" + DateTime.Now.ToString("MM_dd_yyy_HH_mm_ss") + ".xls";           
                currentFile.Save(filePath);
                lstFile.Add(filePath);

            }

This function of adding value in sheet is might be useful:

private void AddValue(int i, Excel.Worksheet workSheet, DataTable dtAltTag, int Row)
        {
            //Header Working starts here
            string[] columName = new string[] { "column1", "column2", "column2", "column2", "column2" }; //add header as per you requirement
            if (Row == 0)
            {
                for (int c = 0; c < columName.Length; c++)
                {
                    workSheet.Cells[0, c] = new Excel.Cell(columName[c]);
                }
            }

            //add data
            for (int c = 0; c < columName.Length; c++)
            {
                workSheet.Cells[Row + 1, c] = new Excel.Cell(dtAltTag.Rows[i].ItemArray[c].ToString());            
            }


        }