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用asp.net实现将上传的图片变小存入数据库

2024-07-10 13:07:03
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  • 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" type="file" size="10" name="file1" runat="server"> <asp:button id="cmdupload" 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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