mysql – 将图像存储到数据库blob;从db检索到Picturebox
作者:互联网
嗨,我之前发布了这个并获得了一些帮助,但仍然没有可行的解我已经确定感谢最后一次q&我的“保存到数据库”代码以及我的“检索到图片”代码有问题.即使我手动将图片保存在数据库中,它仍然不会撤消.这是我在网上围绕3或4个例子拼凑的代码.理想情况下,如果某人有一些已知的良好代码,并可以指导我,那将是最好的.
Dim filename As String = txtName.Text + ".jpg"
Dim FileSize As UInt32
Dim ImageStream As System.IO.MemoryStream
ImageStream = New System.IO.MemoryStream
PbPicture.Image.Save(ImageStream, System.Drawing.Imaging.ImageFormat.Jpeg)
ReDim rawdata(CInt(ImageStream.Length - 1))
ImageStream.Position = 0
ImageStream.Read(rawdata, 0, CInt(ImageStream.Length))
FileSize = ImageStream.Length
Dim query As String = ("insert into actors (actor_pic, filename, filesize) VALUES (?File, ?FileName, ?FileSize)")
cmd = New MySqlCommand(query, conn)
cmd.Parameters.AddWithValue("?FileName", filename)
cmd.Parameters.AddWithValue("?FileSize", FileSize)
cmd.Parameters.AddWithValue("?File", rawData)
cmd.ExecuteNonQuery()
MessageBox.Show("File Inserted into database successfully!", _
"Success!", MessageBoxButtons.OK, MessageBoxIcon.Asterisk)
![在此处输入图像说明] [1]
‘***使用以下代码回到图片框:
Private Sub GetPicture()
'This retrieves the pictures from a mysql DB and buffers the rawdata into a memorystream
Dim FileSize As UInt32
Dim rawData() As Byte
Dim conn As New MySqlConnection(connStr)
conn.Open()
conn.ChangeDatabase("psdb")
Dim cmd As New MySqlCommand("SELECT actor_pic, filesize, filename FROM actors WHERE actor_name = ?autoid", conn)
Cmd.Parameters.AddWithValue("?autoid", Actor1Box.Text)
Reader = cmd.ExecuteReader
Reader.Read()
'data is in memory
FileSize = Reader.GetUInt32(Reader.GetOrdinal("filesize"))
rawData = New Byte(FileSize) {}
'get the bytes and filesize
Reader.GetBytes(Reader.GetOrdinal("actor_pic"), 0, rawData, 0, FileSize)
Dim ad As New System.IO.MemoryStream(100000)
' Dim bm As New Bitmap
ad.Write(rawData, 0, FileSize)
Dim im As Image = Image.FromStream(ad) * "error occurs here" (see below)
Actor1Pic.Image = im
Reader.Close()
conn.Close()
conn.Dispose()
ad.Dispose()
解决方法:
好吧,既然没有得到任何帮助,我就对这个问题嗤之以鼻,并最终让它发挥作用.这是我的工作代码.
从Picturebox中保存到MySQL(pbPicture)
Dim filename As String = txtName.Text + ".jpg"
Dim FileSize As UInt32
conn.Close()
Dim mstream As New System.IO.MemoryStream()
PbPicture.Image.Save(mstream, System.Drawing.Imaging.ImageFormat.Jpeg)
Dim arrImage() As Byte = mstream.GetBuffer()
FileSize = mstream.Length
Dim sqlcmd As New MySqlCommand
Dim sql As String
mstream.Close()
sql = "insert into [your table] (picture, filename, filesize)
VALUES(@File, @FileName, @FileSize)"
Try
conn.Open()
With sqlcmd
.CommandText = sql
.Connection = conn
.Parameters.AddWithValue("@FileName", filename)
.Parameters.AddWithValue("@FileSize", FileSize)
.Parameters.AddWithValue("@File", arrImage)
.ExecuteNonQuery()
End With
Catch ex As Exception
MsgBox(ex.Message)
Finally
conn.Close()
End Try
从MySQL db加载回到Picturebox
Dim adapter As New MySqlDataAdapter
adapter.SelectCommand = Cmd
data = New DataTable
adapter = New MySqlDataAdapter("select picture from [yourtable]", conn)
注意!!只能在picturebox中放一张图片,所以显然这个查询只能为你返回一条记录
commandbuild = New MySqlCommandBuilder(adapter)
adapter.Fill(data)
Dim lb() As Byte = data.Rows(0).Item("picture")
Dim lstr As New System.IO.MemoryStream(lb)
PbPicture.Image = Image.FromStream(lstr)
PbPicture.SizeMode = PictureBoxSizeMode.StretchImage
lstr.Close()
标签:picturebox,mysql,image,vb-net,blob 来源: https://codeday.me/bug/20190916/1806759.html