Create Excel Sheet daynamicaly - C# / asp.NET

// you just need to import below namespaces

using System.IO;
using System.Reflection;
using Excel = Microsoft.Office.Interop.Excel;

//

your_method()
{

DataTable dt = new DataTable();// Imagine you have 2 data column in the data table...
dt.DataSource = passedTable;

Excel.Application xlApp = new Excel.Application();
Excel.Workbook wb = xlApp.Application.Workbooks.Add(true);
xlApp.Visible = true;
Excel.Worksheet ws = (Excel.Worksheet)xlApp.ActiveSheet;
ws.Activate();

xlApp.Cells[1,1] = dt.Rows[0][0].ToString(); 

// Keep in mind that Excel
//index counting is starting from row index 1 and column index 1.
//Therefore it is little bit differ form a data table.
// data table row count starts from 0 as well as column.

//Finally you can save it...
wb.SaveAs(repName, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Excel.XlSaveAsAccessMode.xlNoChange, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);

// Also if you want to create a cell range in your excel sheet then you can create it as below

Excel.Range range = xlApp.get_Range(xlApp.Cells[1, 1], xlApp.Cells[1, 5]);

// Them if you want to give a cell border to that range it is below..

rangeSub_ColumnName.Borders.LineStyle = Excel.XlLineStyle.xlContinuous;

//Also if you want to bold the font color as below,

rangeSubColumnHeadings.Font.Bold = true;

}