Export to Excel function working in localhost but not in published website - asp.net

Question

I have this code to export my GridViews to Excel, it works in localhost but after deploying it does not work. The error I received upon clicking my export button is Runtime Error.
protected void EXPORT_BUTTON_Click(object sender, EventArgs e)
{
Microsoft.Office.Interop.Excel._Application app = new Microsoft.Office.Interop.Excel.Application();
// creating new WorkBook within Excel application
Microsoft.Office.Interop.Excel._Workbook workbook = app.Workbooks.Add(Type.Missing);
String DATA1 = "DATA1";
String DATA2 = "DATA2";
ExportToExcel(app, workbook, DATA_1, DATA1);
workbook.Worksheets["Sheet1"].Delete();
workbook.Worksheets["Sheet2"].Delete();
workbook.Worksheets["Sheet3"].Delete();
ExportToExcel(app, workbook, DATA_2, DATA2);
string FolderPath = ServerName + DirectoryLocation + DirectoryFolder + ExportsFolder;
var filename = #"EXCEL_" + datetime.ToString("dd-MM-yyyy_hh-mm-ss") + ".xlsx";
workbook.SaveAs(FolderPath + filename, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlExclusive, Type.Missing, Type.Missing, Type.Missing, Type.Missing);
workbook.Close();
app.Quit();
Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
Response.AddHeader("content-disposition", "attachment; filename=" + filename + ";");
Response.TransmitFile(FolderPath + filename);
Response.Flush();
Response.End();
}
public void ExportToExcel(Microsoft.Office.Interop.Excel._Application app, Microsoft.Office.Interop.Excel._Workbook workbook, GridView gridview, string SheetName)
{
// see the excel sheet behind the program
app.Visible = false;
Excel.Worksheet worksheet = (Excel.Worksheet)workbook.Worksheets.Add();
// changing the name of active sheet
worksheet.Name = SheetName;
// storing header part in Excel
for (int i = 1; i < gridview.Columns.Count + 1; i++)
{
worksheet.Cells[1, i] = gridview.Columns[i - 1].HeaderText;
}
// storing Each row and column value to excel sheet
for (int i = 0; i < gridview.Rows.Count - 1; i++)
{
for (int j = 0; j < gridview.Columns.Count; j++)
{
worksheet.Cells[i + 2, j + 1] = gridview.Rows[i].Cells[j].Text.ToString();
}
}
}

Answer 1

I solved my question using EPPLUS, EPPlus is a .net library that reads and writes Excel 2007/2010 files using the Open Office Xml format (xlsx). It does not require excel to be installed on the server machines. thanks.
The codes below is an reference:
protected void ExportToExcel_Click(object sender, EventArgs e)
{
var products = GetProducts();
GridView1.DataSource = products;
GridView1.DataBind();
ExcelPackage excel = new ExcelPackage();
var workSheet = excel.Workbook.Worksheets.Add("Products");
var totalCols = GridView1.Rows[0].Cells.Count;
var totalRows = GridView1.Rows.Count;
var headerRow = GridView1.HeaderRow;
for (var i = 1; i <= totalCols; i++ )
{
workSheet.Cells[1, i].Value = headerRow.Cells[i - 1].Text;
}
for (var j = 1; j <= totalRows; j++ )
{
for (var i = 1; i <= totalCols; i++)
{
var product = products.ElementAt(j-1);
workSheet.Cells[j + 1, i].Value = product.GetType().GetProperty(headerRow.Cells[i - 1].Text).GetValue(product, null);
}
}
using (var memoryStream = new MemoryStream())
{
Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
Response.AddHeader("content-disposition", "attachment; filename=products.xlsx");
excel.SaveAs(memoryStream);
memoryStream.WriteTo(Response.OutputStream);
Response.Flush();
Response.End();
}
}

Answer 2

'Microsoft.Office.Interop.Excel' means that Microsoft Office Runtime must be installed to make this code work.
Exporting data using Microsoft.Office.Interop.Excel is avoided, since it needs application installation on server, is poorly scalable, and is against MS Office licence conditions.
I suggest other ways, like text-csv exporting that will meet better performance on a server.
protected void EXPORT_BUTTON_Click(object sender, EventArgs e)
{
...
StringBuilder sb = new StringBuilder();
// storing header part in Excel
for (int i = 1; i < gridview.Columns.Count + 1; i++)
{
sb.Append (gridview.Columns[i - 1].HeaderText);
stringBuilder.Append(",");
}
sb.Append(Environment.NewLine);
// storing Each row and column value to excel sheet
for (int i = 0; i < gridview.Rows.Count - 1; i++)
{
for (int j = 0; j < gridview.Columns.Count; j++)
{
sb.Append (gridview.Rows[i].Cells[j].Text.ToString());
stringBuilder.Append(",");
}
sb.Append(Environment.NewLine);
}
WriteToCSV(sb.ToString();
}
public static void WriteToCSV(string text, string fileName)
{
string attachment = "attachment; filename="+fileName+DateTime.Now.ToString("yy-MM-dd")+".csv";
HttpContext.Current.Response.Clear();
HttpContext.Current.Response.ClearHeaders();
HttpContext.Current.Response.ClearContent();
HttpContext.Current.Response.AddHeader("content-disposition", attachment);
HttpContext.Current.Response.ContentType = "text/csv;charset=utf8";
HttpContext.Current.Response.AddHeader("Pragma", "public");
HttpContext.Current.Response.Write('\uFEFF'); //this is BOM
HttpContext.Current.Response.Write(text);
HttpContext.Current.Response.End();
}

Answer 3

The reason it is failing is you don't have Excel installed. There are other options here (such as converting to CSV file), but if you want to use your code as is, the simplest way is to probably just install Excel on the server !