asp.net - 如何通过 VB.Net 使用 Asp.Net 在 SQL Server 2008R2 中保存和检索图像

Question

我有一个 FileUploadfileupload2控件和一个图像框控件image1。现在我想保存浏览图像并在浏览路径时将其显示在图像框上。我正在编写如下代码。

该代码有什么问题以及我在浏览路径时如何在图像框中显示它？

Protected Sub btnsave_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnsave.Click
    Connection()

    Dim cmd As New SqlCommand
    cmd.Connection = cn
    cmd.CommandText = "INSERT INTO Personal_info (image_id,pic)VALUES (@image_id,@pic)"

    cmd.Parameters.Add("@image_id", SqlDbType.VarChar, 200)
    cmd.Parameters.Add("@pic", SqlDbType.Image, 200)

    cmd.Parameters("@image_id").Value = txtid.Text
    cmd.Parameters("@pic").Value = FileUpload2.FileBytes

    Dim i = -1

    i = cmd.ExecuteNonQuery

    If i = -1 Then
        lblMessage.ForeColor = Drawing.Color.Red
        lblMessage.Text = "Fail to Save"
        'MsgBox("Fail", MsgBoxStyle.OkOnly, "Error")
    Else
        lblMessage.ForeColor = Drawing.Color.Green
        lblMessage.Text = "Success to Save"
    End If
End Sub

Answer 1

要在图像框中显示图像，您需要提供图像路径或 url。您不能直接从数据库中读取它。

一种方法是

1. 从数据库中检索图像
2. 将图像保存在服务器中

3. 将图像框传递给图像服务器路径

   '1. retrieve the imange from the database
   Dim cmd As New SqlCommand
   cmd.Connection = cn
   cmd.CommandText = "SELECT pic FROM Personal_info  WHERE image_id=@image_id;"
   
   cmd.Parameters.Add("@image_id", image_id)
   
   Dim rd As SqlDataReader = cmd.ExecuteReader
   Dim MyData() As Byte
   If rd.Read Then
       If rd("pic").ToString <> Nothing Then
           MyData = rd("pic")
       End If
   
   End If
   
   '2. save the image in the server
   Dim oFileStream As New System.IO.FileStream(System.AppDomain.CurrentDomain.BaseDirectory & "image\image.jpg", System.IO.FileMode.Create, IO.FileAccess.ReadWrite)
   oFileStream.Write(MyData, 0, MyData.Length)
   oFileStream.Close()
   
   '3. pass the image box the image server path
   image1.ImageUrl = "~/image/image.jpg"