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關於NPOI的一點補充和示例
最近看到很多人分享NPOI的用法.
但是很多都不是完整示例或者並沒有實戰效果.
剛好最近有個VB.NET的項目有升級原有的oledb select sheet$的做法.
很明顯,NPOI有更好的穩定性和兼容性.
2進制的處理方式排除了server和client端有沒有office excel的諸多影響和限制.如office版本,系統編碼問題.以及server端是否需要安裝office excel.
2.0版本之後更是支持.xlsx格式等等..
那直接上代碼:
要先引用HSSF和XSSF(for .xlsx support).
下載Excel.沒有寫下載成xlsx的格式了.沒必要.如果一定要download成xlsx.使用對應的XSSF命名空間下的XSSFWorkbook等即可
Imports NPOI.HSSF.UserModelImports NPOI.XSSF.UserModel Public Shared Function DownLoadToExcel(ByVal dt As DataTable) Dim book As HSSFWorkbook = New HSSFWorkbook() Dim sheet As HSSFSheet = book.CreateSheet("Your_Sheet_Name") Dim row As HSSFRow = sheet.CreateRow(0) For i = 0 To dt.Columns.Count - 1 row.CreateCell(i).SetCellValue(dt.Columns(i).ColumnName) Next For i = 0 To dt.Rows.Count - 1 Dim row2 As HSSFRow = sheet.CreateRow(i + 1) For j = 0 To dt.Columns.Count - 1 row2.CreateCell(j).SetCellValue(dt.Rows(i)(j).ToString) Next Next Dim ms As System.IO.MemoryStream = New System.IO.MemoryStream() book.Write(ms) HttpContext.Current.Response.AddHeader("Content-Disposition", String.Format("attachment;filename={0}.xls", Now.ToString)) HttpContext.Current.Response.BinaryWrite(ms.ToArray()) book = Nothing ms.Close() ms.Dispose() End Function
上傳EXCEL.
通常我們實際做項目的時候,需要通過導入excel再進行處理而不是單純的重複insert DB.
那我們直接獲取datatable.
支持xls和.xlsx格式上傳. 這裏的lofile 就是HtmlInputFile控件.調用方法的時候直接將這個對象傳過來即可.
我這裏是web項目.如果是winform.lofile完全不用save之後再處理.直接傳path過來就可以.同樣請將對應的HttpContext改成Context.
Public Shared Function GetTabelFromExcel(ByVal lofile As HtmlInputFile) As DataTable Dim filepath As String = Path.Combine(HttpContext.Current.Server.MapPath("bin"), Path.GetFileName(lofile.PostedFile.FileName)) Dim fileExt As String = Path.GetExtension(lofile.PostedFile.FileName) Try lofile.PostedFile.SaveAs(filepath) Dim tempname As String = Guid.NewGuid().ToString Dim tempfilepath As String = Path.Combine(HttpContext.Current.Server.MapPath("bin"), tempname & fileExt) File.Move(filepath, tempfilepath) File.Delete(filepath) filepath = tempfilepath If fileExt = ".xlsx" Then ‘.xlsx 2007 Try Dim wb As XSSFWorkbook Dim file As System.IO.FileStream = New System.IO.FileStream(filepath, System.IO.FileMode.Open, System.IO.FileAccess.Read) Using file wb = New XSSFWorkbook(file) End Using Dim sheet As XSSFSheet = CType(wb.GetSheetAt(0), XSSFSheet) Dim rows As System.Collections.IEnumerator = sheet.GetRowEnumerator() Dim dt As DataTable = New DataTable() For i As Integer = 0 To CInt(sheet.GetRow(0).LastCellNum) - 1 dt.Columns.Add(System.Convert.ToChar(65 + i).ToString()) Next While rows.MoveNext() Dim row As XSSFRow = CType(rows.Current, XSSFRow) Dim dr As DataRow = dt.NewRow() For j As Integer = 0 To CInt(row.LastCellNum) - 1 Dim cell As XSSFCell = CType(row.GetCell(j), XSSFCell) If cell Is Nothing Then dr(j) = Nothing Else dr(j) = cell.ToString() End If Next dt.Rows.Add(dr) End While dt.Rows.RemoveAt(0) Return dt Catch e As System.Exception Throw New Exception("文件第一行不允許有空白欄位或文件正在使用,請先關閉正在打開的文件!" & e.Message) End Try ElseIf fileExt = ".xls" Then ‘office 2003 Try Dim wb As HSSFWorkbook Dim file As System.IO.FileStream = New System.IO.FileStream(filepath, System.IO.FileMode.Open, System.IO.FileAccess.Read) Using file wb = New HSSFWorkbook(file) End Using Dim sheet As HSSFSheet = CType(wb.GetSheetAt(0), HSSFSheet) Dim rows As System.Collections.IEnumerator = sheet.GetRowEnumerator() Dim dt As DataTable = New DataTable() For i As Integer = 0 To CInt(sheet.GetRow(0).LastCellNum) - 1 dt.Columns.Add(System.Convert.ToChar(65 + i).ToString()) Next While rows.MoveNext() Dim row As HSSFRow = CType(rows.Current, HSSFRow) Dim dr As DataRow = dt.NewRow() For j As Integer = 0 To CInt(row.LastCellNum) - 1 Dim cell As HSSFCell = CType(row.GetCell(j), HSSFCell) If cell Is Nothing Then dr(j) = Nothing Else dr(j) = cell.ToString() End If Next dt.Rows.Add(dr) End While dt.Rows.RemoveAt(0) Return dt Catch e As System.Exception Throw New Exception("文件第一行不允許有空白欄位或文件正在使用,請先關閉正在打開的文件!" & e.Message) End Try Else Throw New Exception("請選擇office excel文件!") End If Catch ex As Exception Throw New Exception("請選擇office excel文件!" & ex.Message) Finally File.Delete(filepath) End Try End Function得到datatable之後請自行處理.
關於NPOI的一點補充和示例
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