[ASP.net] Create excel by NPOI

在asp.net要產生excel可以用很方便的原件NPOI，
要怎麼使用這邊有個範例

1. 請先去NPOI Project下載最新的dll
2. reference NPOI 並且import
   Imports NPOI.HSSF.UserModel
Imports NPOI.SS.UserModel
Imports NPOI.SS.Util
Imports NPOI.HSSF.Util
Imports NPOI.POIFS.FileSystem
Imports NPOI.HPSF

3. 建立excel的 workbook和第一個sheet
   Dim workbook As New HSSFWorkbook()
Dim sheet As HSSFSheet = workbook.CreateSheet("Sheet")

4. 開始寫入Row資料
   Dim rowIndex As Integer = 0
Dim row As HSSFRow = sheet.CreateRow(rowIndex)
row.CreateCell(0).SetCellValue("Name")
row.CreateCell(1).SetCellValue("Phone")
row.CreateCell(2).SetCellValue("Addess")
row.CreateCell(3).SetCellValue("gender")
row.CreateCell(4).SetCellValue("Email")
rowIndex = +1

5. 寫入檔案
   Dim fileName As String = Server.MapPath(".") + "/test.xls"
Using fileData = New FileStream(fileName, FileMode.Create)
workbook.Write(fileData)
End Using

6. 如果要讓使用者下載可以用下面的code
   Using exportData = New MemoryStream()
workbook.Write(exportData)
Dim saveAsFileName As String = String.Format("test.xls", DateTime.Now).Replace("/", "-")
Response.ContentType = "application/vnd.ms-excel"
Response.AddHeader("Content-Disposition", String.Format("attachment;filename={0}", saveAsFileName))
Response.Clear()
Response.BinaryWrite(exportData.GetBuffer())
Response.[End]()
End Using