從MS Access 2007 DB（VB.net）下載文件

Question

您好我正在創建一個使用VB.net的Windows應用程序，我想知道如何創建一個下載按鈕，以便當用戶點擊它時，它能夠從數據庫中的附件列下載特定的附件。

我已經試圖谷歌我怎麼可以這樣做，但不幸的是，我無法找到答案。我很感激，如果有經驗的人可以指導我編寫這個函數的過程。

Answer 1

使用DAO（添加Microsoft.Office.Interop.Access.Dao.DLL的引用）從Ms-Access數據庫讀取附件字段。

示例代碼：

Imports Microsoft.Office.Interop.Access 
Public Class Form1 
    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click 
     Dim FileName = "c:\WindowsApplication1\Database1.accdb" 

     'Directory location where attachment files will be stored. 
     Dim Path = "c:\WindowsApplication1\" 

     Dim engine As New Dao.DBEngine 
     Dim database As Dao.Database = engine.OpenDatabase(FileName) 

     Dim rs As Dao.Recordset = database.OpenRecordset("select MyAttachmentField from TableName") 
     While Not rs.EOF 
      Dim rs1 As Dao.Recordset2 = rs.Fields("MyAttachmentField").Value 
      While Not rs1.EOF 
       Dim fName As String = Path & rs1("FileName").Value 
       Dim fld As Dao.Field2 = rs1("FileData") 
       'Delete a file if same named file exists 
       System.IO.File.Delete(fName) 
       fld.SaveToFile(fName) 
       rs1.MoveNext() 
      End While 
     rs.MoveNext() 
     End While 
    End Sub 
End Class