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| 技术资料 > .Net专区 > Asp.Net开发 : 用asp.net实现将上传的图片变小存入数据库 |
用asp.net实现将上传的图片变小存入数据库
March 25,2004 |
我校的学生网：www.ehang.com.cn中有校友录和图库等的项目有上传图片的功能，我将图片数据存入数据库中，需要将图片变小后和原图片一块存入数据库中，这样先可显示很多小图，点击后再显示大图！在asp.net中是这么做的：
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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