Dataset to excel in C# (using microsoft.office.interop.excel)

DataTable dt = new DataTable();

//Add Datacolumn
DataColumn workCol = dt.Columns.Add("FirstName", 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"] = "Faisal";            
newRow["Blog"] = "http://google.com/";
newRow["city"] = "Mysore";
newRow["country"] = "India";

dt.Rows.Add(newRow);

DataSet ds = new DataSet();
ds.Tables.Add(dt);



ExportDataSetToExcel(ds, "E:\\Tst.xlsx");


private void ExportDataSetToExcel(DataSet ds, string _filename)
{
    //Creae an Excel application instance
    Microsoft.Office.Interop.Excel.Application excelApp = new Microsoft.Office.Interop.Excel.Application();
    
    //Create an Excel workbook instance and open it from the predefined location
    //ERROR
    Microsoft.Office.Interop.Excel.Workbook excelWorkBook = excelApp.Workbooks.Open(_filename);
    
    
    foreach (DataTable table in ds.Tables)
    {
        //Add a new worksheet to workbook with the Datatable name
        Microsoft.Office.Interop.Excel.Worksheet excelWorkSheet = excelWorkBook.Sheets.Add();
        excelWorkSheet.Name = table.TableName;
        
        for (int i = 1; i < table.Columns.Count + 1; i++)
        {
            excelWorkSheet.Cells[1, i] = table.Columns[i - 1].ColumnName;
        }
        
        for (int j = 0; j < table.Rows.Count; j++)
        {
            for (int k = 0; k < table.Columns.Count; k++)
            {
             excelWorkSheet.Cells[j+2, k+1] = table.Rows[j].ItemArray[k].ToString();
            }
        }
    }

    excelWorkBook.Save();
    excelWorkBook.Close();
    excelApp.Quit();
}