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用asp.net实现将上传的图片变小存入数据库

减小字体 增大字体 作者:不详  来源:不详  发布时间:2006-8-14 9:43:50
     changimage.aspx中代码:
  <%@ Page Language="vb" AutoEventWireup="false" Codebehind="changimage.aspx.vb" Inherits="uploadimage.changimage"%>
  <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
  <HTML>
  <HEAD>
  <title></title>
  <meta name="GENERATOR" content="Microsoft Visual Studio.NET 7.0">
  <meta name="CODE_LANGUAGE" content="Visual Basic 7.0">
  <meta name="vs_defaultClientScript" content="JavaScript">
  <meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
  </HEAD>
  <body MS_POSITIONING="GridLayout">
  <form id="Form1" method="post" enctype="multipart/form-data" runat="server">
  <FONT face="宋体"><INPUT id="File1" style="Z-INDEX: 101; LEFT: 291px; WIDTH: 180px; POSITION: absolute; TOP: 119px; HEIGHT: 45px" type="file" size="10" name="File1" runat="server"> <asp:Button id="cmdupload" style="Z-INDEX: 103; LEFT: 402px; POSITION: absolute; TOP: 194px" runat="server" Text="上传图片" Width="81px" Height="42px"></asp:Button>
  </FONT>
  </form>
  </body>
  </HTML>
  changimage.aspx.vb中代码如下:
  Public Class changimage
  Inherits System.Web.UI.Page
  Protected WithEvents cmddemo As System.Web.UI.WebControls.Button
  Protected WithEvents cmdupload As System.Web.UI.WebControls.Button
  Protected WithEvents SqlConn As System.Data.SqlClient.SqlConnection
  Protected WithEvents SqlComm As System.Data.SqlClient.SqlCommand
  Protected WithEvents File1 As System.Web.UI.HtmlControls.HtmlInputFile #Region " Web Form Designer Generated Code " 'This call is required by the Web Form Designer.
  <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
  Me.SqlConn = New System.Data.SqlClient.SqlConnection()
  Me.SqlComm = New System.Data.SqlClient.SqlCommand() End Sub Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init
  Form Designer
  InitializeComponent()
  End Sub #End Region Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
  End Sub Private Sub cmdupload_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdupload.Click
  Dim image As System.Drawing.Image, newimage As System.Drawing.Image
  Dim callb As System.Drawing.Image.GetThumbnailImageAbort
  Dim f As System.IO.File, fs As System.IO.FileStream
  Dim temppath As String
  Dim bigdata As Byte(), smalldata As Byte() '大图片数据、小图片数据
  Dim pic As System.Data.SqlClient.SqlParameter, picsmall As System.Data.SqlClient.SqlParameter
  '检察上传文件是否合标准,check函数是我根据网站需要写的了
  If check(File1.PostedFile.FileName) <> "ok" Then
  Response.Write(check(File1.PostedFile.FileName))
  Exit Sub
  End If
  '设置临时路径,为了防止多用户访问时的冲突,设了一个application对象
  If Application("image") = "" Then
  Application("image") = 0
  End If
  Application.Lock()
  temppath = Server.MapPath(CStr(Application("image"))) '临时路径
  Application("image") = Application("image") + 1
  Application.UnLock()
  '读取图片的数据
  ReDim bigdata((Me.File1.PostedFile.InputStream.Length)
  Me.File1.PostedFile.InputStream.Read(bigdata, 0, UBound(bigdata)) '将原图片数据读到bigdata中
  '改变图片的大小
  image = System.Drawing.Image.FromStream(Me.File1.PostedFile.InputStream)
  'newimage里面的size也可另外设置,我只用了80*60和60*80两种
  If image.Width > image.Height Then
  newimage = image.GetThumbnailImage(80, 60, callb, New System.IntPtr(0))
  Else
  newimage = image.GetThumbnailImage(60, 80, callb, New System.IntPtr(0))
  End If
  image.Dispose()
  '将新图片及图片变小后存到临时路径中
  newimage.Save(temppath, System.Drawing.Imaging.ImageFormat.Jpeg)
  newimage.Dispose()
  '读取临时文件数据到smalldata中
  fs = New System.IO.FileStream(temppath, IO.FileMode.Open, IO.FileAccess.Read)
  ReDim smalldata(fs.Length)
  fs.Read(smalldata, 0, UBound(smalldata))
  fs.Close()
  '上述获得小图片的方法我原本想用system.io.memorystream的,可是行不通:代码如下:
  'dim m as system.io.memorystream
  'm=new system.io.memorystream()
  'newimage.save(m,System.Drawing.Imaging.ImageFormat.Jpeg)
  'redim smalldata(m.length)
  'm.read(smalldata,0,m.length)
  '可是上述方法读出来的smalldata全是空的,不知道原因,请指教
  '删除临时文件
  If f.Exists(temppath) Then
  f.Delete(temppath)
  End If
  '将数据加入数据库中
  '由于数据库中有image字段,我用sql插不进去,就用一个存储过程
  '请教各位大虾用sql语句插入有image字段的表该怎么写
  '用insert into talbe(pic,picsmall) values("&bigdata&","&smalldata&")这样不行,用'"&bigdata&"'也不行呀!
  SqlConn = New System.Data.SqlClient.SqlConnection(connstr) '可自己设置connstr连接数据库服务器
  SqlComm = New System.Data.SqlClient.SqlCommand()
  SqlComm.CommandType = CommandType.StoredProcedure
  SqlComm.CommandText = "dbo.image"
  pic = New System.Data.SqlClient.SqlParameter("@pic", SqlDbType.Image)
  pic.Value = bigdata
  picsmall = New System.Data.SqlClient.SqlParameter("@picsmall", SqlDbType.Image)
  picsmall.Value = smalldata
  SqlComm.Parameters.Add(pic)
  SqlComm.Parameters.Add(picsmall)
  SqlComm.Connection = SqlConn
  SqlComm.Connection.Open()
  SqlComm.ExecuteNonQuery()
  SqlComm.Connection.Close()
  SqlComm.Dispose()
  SqlConn.Dispose()
  End Sub
  End Class dbo.image存储过程如下:
  create proc dbo.image
  @pic image,
  @picsmall image
  as
  insert into table(pic,picsmall) values (@pic,@picsmall)
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