C# Export DataTable as Excel file

/// <summary>
/// Export DataTable data to Excel/// </summary>
/// <param name="data"></param>
/// <param name="filepath"></param>
public static void DataTableExport(DataTable data, string filepath)
{
    try
    {
        //Workbook book = new Workbook("E:\\"); //Open the workbook        Workbook book = new Workbook(); //Create a workbook        Worksheet sheet = [0]; //Create a worksheet        Cells cells = ; //Cell        //Create style         style = [()];
        [].LineStyle = ; //Application boundary line Left boundary line        [].LineStyle = ; //Apply the boundary line Right boundary line        [].LineStyle = ; //Application boundary line upper boundary line        [].LineStyle = ; //Application boundary line Lower boundary line         = ; //Horizontal alignment of cell content text centered         = "Songyi"; //Font         = true; //Set bold         = 11; //Set font size        // = (153, 204, 0); // Background color        // = ; // Background style        // = true; // Cell contents automatically wrap        
        //File data        int Colnum = ;//Table column count        int Rownum = ;//Table row count        //Generate row column name row        for (int i = 0; i < Colnum; i++)
        {
            cells[0, i].PutValue([i].ColumnName); //Add a header            cells[0, i].SetStyle(style); //Add style            //(i, [i]. * 2 + 1.5); //Custom column width            //(0, 30); //Custom high        }
        //Generate data row        for (int i = 0; i < Rownum; i++)
        {
            for (int k = 0; k < Colnum; k++)
            {
                cells[1 + i, k].PutValue([i][k].ToString()); //Add data                cells[1 + i, k].SetStyle(style); //Add style            }
            cells[1 + i, 5].Formula = "=B" + (2 + i) + "+C" + (2 + i);//Set calculation formulas for cells to calculate the total number of students in the class        }
        (); //Adaptive width        (filepath); //save        ();
    }
    catch (Exception e)
    {
        ("An error occurred when generating excel:" + );
    }
}

public void ToExcel(DataTable dt)
    {
        #region 3s  
        var FilePath = @"D:\ToExcel\";//Generate Excel file path        DeleteFile(FilePath);
        //Create a brand new workbook        var workbook = new HSSFWorkbook();//A sheet can be up to 65536 lines        var count = 0;
        for (double i = 0; i < () / (65534); i++)//One tab of each Excel file can only store 65536 lines of data        {
            var row_index = 0;
            //Create Sheet            ("Sheet" + i);
            //Get the Sheet object based on the Sheet name            var sheet = ("Sheet" + i);
            IRow row;
            row = (row_index);

            //Write the title            for (int j = 0; j < ; j++)
            {
                (j).SetCellValue([j].());
            }
            row = (++row_index);

            //Write data            for (int j = 0; j < ( - count > 65534 ? 65534 :  - count); j++)
            {
                var r = [j + count];
                for (int k = 0; k <; k++)
                {
                    (k).SetCellValue(r[k].ToString());

                    //If it is a number, determine whether it needs to be converted to a number                    //if (IsNumeric(r[k].ToString()))
                    //{
                    //    (k).SetCellValue((r[k].ToString()));
                    //}
                    //else
                    //{
                    //    (k).SetCellValue(r[k].ToString());
                    //}
                }

                row = (++row_index);
            }
            count += row_index - 2;
        }
        //Save Workbook method 1: Save it to the server in file form (a file will be generated every time you export it, use it with caution)        var FileName = ("yyyyMMddHHmmss") + ".xls";

        var sw = (FilePath + FileName);
        (sw);
        ();
        var EC = new ExcelConverter();
        (Response, FilePath + FileName);
        #endregion
    }