Export GridView to multiple Excel sheet

Doing this with EPPlus is a piece of cake. No Interop assemblies required and literally 2 lines of code do all the magic:

ws.Cells["A1"].LoadFromDataTable(dt1, true);
ws2.Cells["A1"].LoadFromDataTable(dt2, true);

Complete code:

protected void ExportExcel_Click(object sender, EventArgs e)
{

     //LinQ Query for dt2
    var query = (from c in dt.AsEnumerable()
    select new {id= c.Field<string>("id"),name=c.Field<string>("name"),city=c.Field<string>("city")}) ;
    DataTable dt2 = new DataTable();
    dt2=query.CopyToDatatable();

    //DataTable dt1
    DataTable dt1 =new DataTable();
    mySqlDataAdapter.Fill(dt1);

    using (ExcelPackage pck = new ExcelPackage())
    {
        ExcelWorksheet ws = pck.Workbook.Worksheets.Add("Page 1");
        ExcelWorksheet ws2 = pck.Workbook.Worksheets.Add("Page 2");

        ws.Cells["A1"].LoadFromDataTable(dt1, true);
        ws2.Cells["A1"].LoadFromDataTable(dt2, true);

        //Write it back to the client
        Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
        Response.AddHeader("content-disposition", "attachment;  filename=ExcelDemo.xlsx");
        Response.BinaryWrite(pck.GetAsByteArray());
        Response.Flush();
        Response.End();
    }
}

Note that I copied and paste it your code to gather the data. I expect these lines to produce a DataTable.