使用LINQ把圖片更新到資料庫

原理很簡單，就是先把圖檔轉成二進位再上傳就行了

程式碼如下

Dim db As New StudnoListDataContext

'把要更新的資料Select出來
Dim StudClass = (From s In db.Stud Where s.stud_no = studno.Text).First
'把PictureBox.Image放到Bitmap
Dim bmp As Bitmap = PictureBox1.Image
'宣告一個MemoryStream
Dim st As New MemoryStream
'把圖片放到MemoryStream裡面
bmp.Save(st, System.Drawing.Imaging.ImageFormat.Jpeg)
st.Position = 0

'把MemoryStream裡的資料轉成二進位
Dim WriteByte(st.Length - 1) As Byte
If st.CanRead Then
      st.Read(WriteByte, 0, st.Length)
      st.Close()
End If

'把WriteByte放到Linq的二進位欄位
StudClass.studimg = WriteByte
'更新上去
db.SubmitChanges()