将DataTable导出到Excel文件

时间:2009-11-17 05:02:30

标签: c# asp.net excel datatable export

我有一个包含30多列和6500多行的DataTable。我需要将整个DataTable值转储到Excel文件中。任何人都可以帮助使用C#代码。我需要每个列值都在一个单元格中。确切地说,我需要Excel文件中的DataTable的精确副本。请帮助。

谢谢, VIX

14 个答案:

答案 0 :(得分:67)

使用此代码...

    dt = city.GetAllCity();//your datatable
    string attachment = "attachment; filename=city.xls";
    Response.ClearContent();
    Response.AddHeader("content-disposition", attachment);
    Response.ContentType = "application/vnd.ms-excel";
    string tab = "";
    foreach (DataColumn dc in dt.Columns)
    {
        Response.Write(tab + dc.ColumnName);
        tab = "\t";
    }
    Response.Write("\n");
    int i;
    foreach (DataRow dr in dt.Rows)
    {
        tab = "";
        for (i = 0; i < dt.Columns.Count; i++)
        {
            Response.Write(tab + dr[i].ToString());
            tab = "\t";
        }
        Response.Write("\n");
    }
    Response.End();

答案 1 :(得分:10)

此代码段的实施速度可能更快:

// Example data
DataTable table = new DataTable();
table.Columns.AddRange(new[]{ new DataColumn("Key"), new DataColumn("Value") });
foreach (string name in Request.ServerVariables)
    table.Rows.Add(name, Request.ServerVariables[name]);

// This actually makes your HTML output to be downloaded as .xls file
Response.Clear();
Response.ClearContent();
Response.ContentType = "application/octet-stream";
Response.AddHeader("Content-Disposition", "attachment; filename=ExcelFile.xls");

// Create a dynamic control, populate and render it
GridView excel = new GridView();
excel.DataSource = table;
excel.DataBind();
excel.RenderControl(new HtmlTextWriter(Response.Output));

Response.Flush();
Response.End();

答案 2 :(得分:4)

下面的链接用于将数据表导出到C#Code中的excel。

http://royalarun.blogspot.in/2012/01/export-datatable-to-excel-in-c-windows.html

  using System;      
   using System.Data;  
   using System.IO;  
   using System.Windows.Forms;  

    namespace ExportExcel  
    {      
        public partial class ExportDatatabletoExcel : Form  
        {  
            public ExportDatatabletoExcel()  
            {  
                InitializeComponent();  
            }  

            private void Form1_Load(object sender, EventArgs e)
            {

                DataTable dt = new DataTable();

                //Add Datacolumn
                DataColumn workCol = dt.Columns.Add("FirstName", typeof(String));

                dt.Columns.Add("LastName", typeof(String));
                dt.Columns.Add("Blog", typeof(String));
                dt.Columns.Add("City", typeof(String));
                dt.Columns.Add("Country", typeof(String));

                //Add in the datarow
                DataRow newRow = dt.NewRow();

                newRow["firstname"] = "Arun";
                newRow["lastname"] = "Prakash";
                newRow["Blog"] = "http://royalarun.blogspot.com/";
                newRow["city"] = "Coimbatore";
                newRow["country"] = "India";

                dt.Rows.Add(newRow);

                //open file
                StreamWriter wr = new StreamWriter(@"D:\\Book1.xls");

                try
                {

                    for (int i = 0; i < dt.Columns.Count; i++)
                    {
                        wr.Write(dt.Columns[i].ToString().ToUpper() + "\t");
                    }

                    wr.WriteLine();

                    //write rows to excel file
                    for (int i = 0; i < (dt.Rows.Count); i++)
                    {
                        for (int j = 0; j < dt.Columns.Count; j++)
                        {
                            if (dt.Rows[i][j] != null)
                            {
                                wr.Write(Convert.ToString(dt.Rows[i][j]) + "\t");
                            }
                            else
                            {
                                wr.Write("\t");
                            }
                        }
                        //go to next line
                        wr.WriteLine();
                    }
                    //close file
                    wr.Close();
                }
                catch (Exception ex)
                {
                    throw ex;
                }
            }
        }
    }

答案 3 :(得分:3)

这篇文章中的排名最高的答案,但它是CSV文件。它不是实际的Excel文件。因此,打开文件时会收到警告。

我在网上找到的最佳解决方案是使用CloseXML http://closedxml.codeplex.com/ 您还需要打开XML。

 dt = city.GetAllCity();//your datatable
 using (XLWorkbook wb = new XLWorkbook())
    {
        wb.Worksheets.Add(dt);

        Response.Clear();
        Response.Buffer = true;
        Response.Charset = "";
        Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
        Response.AddHeader("content-disposition", "attachment;filename=GridView.xlsx");
        using (MemoryStream MyMemoryStream = new MemoryStream())
        {
            wb.SaveAs(MyMemoryStream);
            MyMemoryStream.WriteTo(Response.OutputStream);
            Response.Flush();
            Response.End();
        }
    }

信用:http://www.aspsnippets.com/Articles/Solution-ASPNet-GridView-Export-to-Excel-The-file-you-are-trying-to-open-is-in-a-different-format-than-specified-by-the-file-extension.aspx

答案 4 :(得分:2)

我在页面中使用此内容。

 public void DTToExcel(DataTable dt)
{
    // dosya isimleri ileride aynı anda birden fazla kullanıcı aynı dosya üzerinde işlem yapmak ister düşüncesiyle guid yapıldı. 
    string FileName = Guid.NewGuid().ToString();

    FileInfo f = new FileInfo(Server.MapPath("Downloads") + string.Format("\\{0}.xlsx", FileName));
    if (f.Exists)
        f.Delete(); // delete the file if it already exist.

    HttpResponse response = HttpContext.Current.Response;
    response.Clear();
    response.ClearHeaders();
    response.ClearContent();
    response.Charset = Encoding.UTF8.WebName;
    response.AddHeader("content-disposition", "attachment; filename=" + FileName + ".xls");
    response.AddHeader("Content-Type", "application/Excel");
    response.ContentType = "application/vnd.xlsx";
    //response.AddHeader("Content-Length", file.Length.ToString());


    // create a string writer
    using (StringWriter sw = new StringWriter())
    {
        using (HtmlTextWriter htw = new HtmlTextWriter(sw)) //datatable'a aldığımız sorguyu bir datagrid'e atayıp html'e çevir.
        {
            // instantiate a datagrid
            DataGrid dg = new DataGrid();
            dg.DataSource = dt;
            dg.DataBind();
            dg.RenderControl(htw);
            response.Write(sw.ToString());
            dg.Dispose();
            dt.Dispose();
            response.End();
        }
    }
}

答案 5 :(得分:1)

            var lines = new List<string>();

            string[] columnNames = dt.Columns.Cast<DataColumn>().
                                              Select(column => column.ColumnName).
                                              ToArray();

            var header = string.Join(",", columnNames);
            lines.Add(header);
            var valueLines = dt.AsEnumerable()
                               .Select(row => string.Join(",", row.ItemArray));
            lines.AddRange(valueLines);
            File.WriteAllLines("excel.csv", lines);

这里dt将您的DataTable传递称为参数

答案 6 :(得分:0)

虽然不是.NET实现,但您可能会发现插件TableTools可能非常高效,具体取决于您的受众。它依赖于闪存,这对于大多数需要实际深入工作然后想要记录表格信息的情况来说不应该是一个问题。

最新版本似乎支持复制到剪贴板,复制到CSV,“。XML”(实际上只是一个名为.xls的制表符分隔文件),PDF格式,或创建一个打印机友好页面版本,显示所有行和隐藏页面内容的其余部分。

我在DataTables网站上找到了扩展程序:http://datatables.net/extras/tabletools/

下载可在插件(附加)页面中找到:http://datatables.net/extras/

据说它是作为DataTables的一部分下载的(因此短语“DataTables包中包含的附加内容”)但我没有在我一直使用的下载中找到它。似乎工作得很好!

答案 7 :(得分:0)

在Excel中打开时,大多数答案实际上都会生成我不具备良好经验的CSV。

这样做的一种方法也是ACE OLEDB Provider(另见connection strings for Excel)。当然,您必须安装和注册提供商。如果安装了Excel,则可以使用它,但这是部署时必须考虑的因素(例如,在Web服务器上)。

在下面的帮助程序类代码中,您必须调用ExportHelper.CreateXlsFromDataTable(dataset.Tables[0], @"C:\tmp\export.xls");

之类的内容
public class ExportHelper
{
    private const string ExcelOleDbConnectionStringTemplate = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties=\"Excel 8.0;HDR=YES\";";

    /// <summary>
    /// Creates the Excel file from items in DataTable and writes them to specified output file.
    /// </summary>
    public static void CreateXlsFromDataTable(DataTable dataTable, string fullFilePath)
    {
        string createTableWithHeaderScript = GenerateCreateTableCommand(dataTable);

        using (var conn = new OleDbConnection(String.Format(ExcelOleDbConnectionStringTemplate, fullFilePath)))
        {
            if (conn.State != ConnectionState.Open)
            {
                conn.Open();
            }

            OleDbCommand cmd = new OleDbCommand(createTableWithHeaderScript, conn);
            cmd.ExecuteNonQuery();

            foreach (DataRow dataExportRow in dataTable.Rows)
            {
                AddNewRow(conn, dataExportRow);
            }
        }
    }

    private static void AddNewRow(OleDbConnection conn, DataRow dataRow)
    {
        string insertCmd = GenerateInsertRowCommand(dataRow);

        using (OleDbCommand cmd = new OleDbCommand(insertCmd, conn))
        {
            AddParametersWithValue(cmd, dataRow);
            cmd.ExecuteNonQuery();
        }
    }

    /// <summary>
    /// Generates the insert row command.
    /// </summary>
    private static string GenerateInsertRowCommand(DataRow dataRow)
    {
        var stringBuilder = new StringBuilder();
        var columns = dataRow.Table.Columns.Cast<DataColumn>().ToList();
        var columnNamesCommaSeparated = string.Join(",", columns.Select(x => x.Caption));
        var questionmarkCommaSeparated = string.Join(",", columns.Select(x => "?"));

        stringBuilder.AppendFormat("INSERT INTO [{0}] (", dataRow.Table.TableName);
        stringBuilder.Append(columnNamesCommaSeparated);
        stringBuilder.Append(") VALUES(");
        stringBuilder.Append(questionmarkCommaSeparated);
        stringBuilder.Append(")");
        return stringBuilder.ToString();
    }

    /// <summary>
    /// Adds the parameters with value.
    /// </summary>
    private static void AddParametersWithValue(OleDbCommand cmd, DataRow dataRow)
    {
        var paramNumber = 1;

        for (int i = 0; i <= dataRow.Table.Columns.Count - 1; i++)
        {
            if (!ReferenceEquals(dataRow.Table.Columns[i].DataType, typeof(int)) && !ReferenceEquals(dataRow.Table.Columns[i].DataType, typeof(decimal)))
            {
                cmd.Parameters.AddWithValue("@p" + paramNumber, dataRow[i].ToString().Replace("'", "''"));
            }
            else
            {
                object value = GetParameterValue(dataRow[i]);
                OleDbParameter parameter = cmd.Parameters.AddWithValue("@p" + paramNumber, value);
                if (value is decimal)
                {
                    parameter.OleDbType = OleDbType.Currency;
                }
            }

            paramNumber = paramNumber + 1;
        }
    }

    /// <summary>
    /// Gets the formatted value for the OleDbParameter.
    /// </summary>
    private static object GetParameterValue(object value)
    {
        if (value is string)
        {
            return value.ToString().Replace("'", "''");
        }
        return value;
    }

    private static string GenerateCreateTableCommand(DataTable tableDefination)
    {
        StringBuilder stringBuilder = new StringBuilder();
        bool firstcol = true;

        stringBuilder.AppendFormat("CREATE TABLE [{0}] (", tableDefination.TableName);

        foreach (DataColumn tableColumn in tableDefination.Columns)
        {
            if (!firstcol)
            {
                stringBuilder.Append(", ");
            }
            firstcol = false;

            string columnDataType = "CHAR(255)";

            switch (tableColumn.DataType.Name)
            {
                case "String":
                    columnDataType = "CHAR(255)";
                    break;
                case "Int32":
                    columnDataType = "INTEGER";
                    break;
                case "Decimal":
                    // Use currency instead of decimal because of bug described at 
                    // http://social.msdn.microsoft.com/Forums/vstudio/en-US/5d6248a5-ef00-4f46-be9d-853207656bcc/localization-trouble-with-oledbparameter-and-decimal?forum=csharpgeneral
                    columnDataType = "CURRENCY";
                    break;
            }

            stringBuilder.AppendFormat("{0} {1}", tableColumn.ColumnName, columnDataType);
        }
        stringBuilder.Append(")");

        return stringBuilder.ToString();
    }
}

答案 8 :(得分:0)

Excel导出的工作代码

 try
        {
            DataTable dt = DS.Tables[0];
            string attachment = "attachment; filename=log.xls";
            Response.ClearContent();
            Response.AddHeader("content-disposition", attachment);
            Response.ContentType = "application/vnd.ms-excel";
            string tab = "";
            foreach (DataColumn dc in dt.Columns)
            {
                Response.Write(tab + dc.ColumnName);
                tab = "\t";
            }
            Response.Write("\n");
            int i;
            foreach (DataRow dr in dt.Rows)
            {
                tab = "";
                for (i = 0; i < dt.Columns.Count; i++)
                {
                    Response.Write(tab + dr[i].ToString());
                    tab = "\t";
                }
                Response.Write("\n");
            }
            Response.End();
        }
        catch (Exception Ex)
        { }

答案 9 :(得分:0)

如果要将带有格式化标题文本的数据表导出到Excel,请尝试这样。

public void ExportFullDetails()
    {
        Int16 id = Convert.ToInt16(Session["id"]);
        DataTable registeredpeople = new DataTable();
        registeredpeople = this.dataAccess.ExportDetails(eventid);

        string attachment = "attachment; filename=Details.xls";
        Response.ClearContent();
        Response.AddHeader("content-disposition", attachment);
        Response.ContentType = "application/vnd.ms-excel";
        string tab = "";


        registeredpeople.Columns["Reg_id"].ColumnName = "Reg. ID";
        registeredpeople.Columns["Name"].ColumnName = "Name";
        registeredpeople.Columns["Reg_country"].ColumnName = "Country";
        registeredpeople.Columns["Reg_city"].ColumnName = "City";
        registeredpeople.Columns["Reg_email"].ColumnName = "Email";
        registeredpeople.Columns["Reg_business_phone"].ColumnName = "Business Phone";
        registeredpeople.Columns["Reg_mobile"].ColumnName = "Mobile";
        registeredpeople.Columns["PositionRole"].ColumnName = "Position";
        registeredpeople.Columns["Reg_work_type"].ColumnName = "Work Type";

        foreach (DataColumn dc in registeredpeople.Columns)
        {
            Response.Write(tab + dc.ColumnName);
            tab = "\t";
        }

        Response.Write("\n");
        int i;
        foreach (DataRow dr in registeredpeople.Rows)
        {
            tab = "";
            for (i = 0; i < registeredpeople.Columns.Count; i++)
            {
                Response.Write(tab + dr[i].ToString());
                tab = "\t";
            }
            Response.Write("\n");
        }
        Response.End();

    }

答案 10 :(得分:0)

我已使用以下代码完成了DataTable到Excel的转换。希望它很容易,无需更改更多只是复制和放大害怕代码用您的变量替换您的变量,它将正常工作。

首先在解决方案文档中创建一个文件夹,然后创建一个Excel文件 MyTemplate.xlsx 。您可以根据您的要求更改这些名称。但请记住,您还必须在代码中更改名称。

请找到以下代码......

    protected void GetExcel_Click(object sender, EventArgs e)
    {            

        ManageTicketBS objManageTicket = new ManageTicketBS();
        DataTable DT = objManageTicket.GetAlldataByDate();   //this function will bring the data in DataTable format, you can use your function instate of that.  

        string DownloadFileName;
        string FolderPath;
        string FileName = "MyTemplate.xlsx";
        DownloadFileName = Path.GetFileNameWithoutExtension(FileName) + new Random().Next(10000, 99999) + Path.GetExtension(FileName);
        FolderPath = ".\\" + DownloadFileName;

        GetParents(Server.MapPath("~/Document/" + FileName), Server.MapPath("~/Document/" + DownloadFileName), DT);

        string path = Server.MapPath("~/Document/" + FolderPath);
        FileInfo file = new FileInfo(path);
        if (file.Exists)
        {
            try
            {
                HttpResponse response = HttpContext.Current.Response;
                response.Clear();
                response.ClearContent();
                response.ClearHeaders();
                response.Buffer = true;
                response.ContentType = MimeType(Path.GetExtension(FolderPath));
                response.AddHeader("Content-Disposition", "attachment;filename=" + DownloadFileName);
                byte[] data = File.ReadAllBytes(path);
                response.BinaryWrite(data);
                HttpContext.Current.ApplicationInstance.CompleteRequest();
                response.End();
            }

            catch (Exception ex)
            {
                ex.ToString();
            }
            finally
            {
                DeleteOrganisationtoSupplierTemplate(path);
            }
        }
    }
    public string GetParents(string FilePath, string TempFilePath, DataTable DTTBL)
    {
        File.Copy(Path.Combine(FilePath), Path.Combine(TempFilePath), true);
        FileInfo file = new FileInfo(TempFilePath);
        try
        {
            DatatableToExcel(DTTBL, TempFilePath, 0);

            return TempFilePath;

        }

        catch (Exception ex)
        {                
            return "";
        }

    }


    public static string MimeType(string Extension)
    {
        string mime = "application/octetstream";
        if (string.IsNullOrEmpty(Extension))
            return mime;
        string ext = Extension.ToLower();
        Microsoft.Win32.RegistryKey rk = Microsoft.Win32.Registry.ClassesRoot.OpenSubKey(ext);
        if (rk != null && rk.GetValue("Content Type") != null)
            mime = rk.GetValue("Content Type").ToString();
        return mime;
    }


    static bool DeleteOrganisationtoSupplierTemplate(string filePath)
    {
        try
        {                
            File.Delete(filePath);
            return true;
        }
        catch (IOException)
        {               
            return false;
        }
    }


    public void DatatableToExcel(DataTable dtable, string pFilePath, int excelSheetIndex=1)
    {

        try
        {
            if (dtable != null && dtable.Rows.Count > 0)
            {
                IWorkbook workbook = null;
                ISheet worksheet = null;

                using (FileStream stream = new FileStream(pFilePath, FileMode.Open, FileAccess.ReadWrite))
                {

                    workbook = WorkbookFactory.Create(stream);
                    worksheet = workbook.GetSheetAt(excelSheetIndex);

                    int iRow = 1;



                    foreach (DataRow row in dtable.Rows)
                    {
                        IRow file = worksheet.CreateRow(iRow);
                        int iCol = 0;
                        foreach (DataColumn column in dtable.Columns)
                        {
                            ICell cell = null;
                            object cellValue = row[iCol];

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

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

                                case "System.DateTime":
                                    if (cellValue != DBNull.Value)
                                    {
                                        cell = file.CreateCell(iCol, CellType.String);
                                        DateTime dateTime = Convert.ToDateTime(cellValue);
                                        cell.SetCellValue(dateTime.ToString("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++;
                    }
                    using (var WritetoExcelfile = new FileStream(pFilePath, FileMode.Create, FileAccess.ReadWrite))
                    {
                        workbook.Write(WritetoExcelfile);
                        WritetoExcelfile.Close();
                        //workbook.Write(stream);
                        stream.Close();
                    }
                }
            }
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }

这段代码你只需要复制&amp;您的脚本中有害生物并添加命名空间,如下所示,还要更改excel文件名,如前所述。

using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;
using NPOI.SS.Util;

答案 11 :(得分:0)

请尝试此操作,这样可以更快地将您的数据表数据导出为ex​​cel。

注意:范围&#34; FW&#34;,我有硬编码是因为我有179列。

public void UpdateExcelApplication(SqlDataTable dataTable)
    {
        var objects = new string[dataTable.Rows.Count, dataTable.Columns.Count];

        var rowIndex = 0;

        foreach (DataRow row in dataTable.Rows)
        {
            var colIndex = 0;

            foreach (DataColumn column in dataTable.Columns)
            {
                objects[rowIndex, colIndex++] = Convert.ToString(row[column]);
            }

            rowIndex++;
        }

        var range = this.workSheet.Range[$"A3:FW{dataTable.Rows.Count + 2}"];
        range.Value = objects;

        this.workSheet.Columns.AutoFit();
        this.workSheet.Rows.AutoFit();
    }

答案 12 :(得分:0)

我有一个项目,我也需要Excel格式的DataTable的精确副本。使用ClosedXML,下面的代码对我来说确实做到了。

using ClosedXML.Excel;

        private void DumpDataTableToExcel(DataTable dt, string SavePathAndFilename)
        {
            try
            {
                using (XLWorkbook excelWorkbook = new XLWorkbook())
                {
                    excelWorkbook.AddWorksheet(dt);
                    excelWorkbook.SaveAs(SavePathAndFilename);
                }
            }
            catch
            {
                //Insert error handling here...
            }
        }

此方法将使用DataTable的列名称作为Excel中的列名称,而DataTable名称本身将是工作表名称。用更少的代码行很难完成所有这些工作。

向您的项目添加ClosedXML同样简单。上面的链接以及直接在nuget.org上都有说明。

答案 13 :(得分:-1)

尝试将此数据导出到与DataTable相同的Excel文件,也可以自定义。

dtDataTable1 = ds.Tables[0];
    try
    {
        Microsoft.Office.Interop.Excel.Application ExcelApp = new Microsoft.Office.Interop.Excel.Application();
        Workbook xlWorkBook = ExcelApp.Workbooks.Add(Microsoft.Office.Interop.Excel.XlWBATemplate.xlWBATWorksheet);

        for (int i = 1; i > 0; i--)
        {
            Sheets xlSheets = null;
            Worksheet xlWorksheet = null;
            //Create Excel sheet
            xlSheets = ExcelApp.Sheets;
            xlWorksheet = (Worksheet)xlSheets.Add(xlSheets[1], Type.Missing, Type.Missing, Type.Missing);
            xlWorksheet.Name = "MY FIRST EXCEL FILE";
            for (int j = 1; j < dtDataTable1.Columns.Count + 1; j++)
            {
                ExcelApp.Cells[i, j] = dtDataTable1.Columns[j - 1].ColumnName;
                ExcelApp.Cells[1, j].Interior.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.Green);
                ExcelApp.Cells[i, j].Font.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.WhiteSmoke);
            }
            // for the data of the excel
            for (int k = 0; k < dtDataTable1.Rows.Count; k++)
            {
                for (int l = 0; l < dtDataTable1.Columns.Count; l++)
                {
                    ExcelApp.Cells[k + 2, l + 1] = dtDataTable1.Rows[k].ItemArray[l].ToString();
                }
            }
            ExcelApp.Columns.AutoFit();
        }
        ((Worksheet)ExcelApp.ActiveWorkbook.Sheets[ExcelApp.ActiveWorkbook.Sheets.Count]).Delete();
        ExcelApp.Visible = true;
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }