数据库中图片存储及读取
2024-07-21 02:22:38
供稿：网友
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开发环境：window 2000、sqlserver2000、.net framework sdk正式版
开发语言：c#、asp.net
简介：数据库中图片存储及读取
说明：在asp中，我们用request.totalbytes、request.binaryread()来上传图片，这个可恶的binaryread()方法非常笨，单个文件上传倒没什么大事，单如果多个图片上专可就花大气力了…！而现在asp.net中将会把解决以前asp中文件上传的种种问题，使你在asp.net中轻轻松松开发出功能强大的上传程序，下面大家看看例子啦。
首先在sql server中建立一个图片存储的数库表，sqlscript如下:
if exists (select * from dbo.sysobjects where id = object_id(n"[dbo].[image]") and objectproperty(id, n"isusertable") = 1)
drop table [dbo].[image]
go
create table [dbo].[image] (
[img_pk] [int] identity (1, 1) not null ,
[img_name] [varchar] (50) null ,
[img_data] [image] null ,
[img_contenttype] [varchar] (50) null
) on [primary] textimage_on [primary]
go
alter table [dbo].[image] with nocheck add
constraint [pk_image] primary key nonclustered
(
[img_pk]
) on [primary]
go
------------------------------------------------------------
一、上传图片:
imgupload.aspx文件:
<%@ page language="c#" codebehind="imgupload.aspx.cs" autoeventwireup="false" inherits="study.uploadimage.imgupload" %>
<!doctype html public "-//w3c//dtd html 4.0 transitional//en" >
<html>
<head>
<title>imgupload</title>
<meta name="generator" content="microsoft visual studio 7.0">
<meta name="code_language" content="c#">
<meta name="vs_defaultclientscript" content="javascript">
<meta name="vs_targetschema" content="http://schemas.microsoft.com/intellisense/ie5">
</head>
<body>
<form enctype="multipart/form-data" runat="server" id="form1" name="form1">
文件名 <input type="text" id="imgname" runat="server" name="imgname">
<br>
选择文件 <input id="uploadfile" type="file" runat="server" name="uploadfile">
<br>
<asp:button text="上传" runat="server" id="button1" />
</form>
<a href="imgview.aspx?id=1" target="_blank">看图</a>
</body>
</html>
codebehind文件:
using system;
using system.collections;
using system.componentmodel;
using system.data;
using system.drawing;
using system.web;
using system.web.sessionstate;
using system.web.ui;
using system.web.ui.webcontrols;
using system.web.ui.htmlcontrols;
using system.io;
using system.data.sqlclient;
namespace study.uploadimage
{
/// <summary>
/// imgupload 的摘要说明。
/// </summary>
public class imgupload : system.web.ui.page
{
protected system.web.ui.webcontrols.button button1;
protected system.web.ui.htmlcontrols.htmlinputtext imgname;
protected system.web.ui.htmlcontrols.htmlinputfile uploadfile;
private void page_load(object sender, system.eventargs e)
{
// 在此处放置用户代码以初始化页面
}
private void button1_click(object sender, system.eventargs e)
{
stream imgstream;
int imglen;
string imgname_value;
string imgcontenttype;
string imguploadedname;
imgstream = uploadfile.postedfile.inputstream;
imglen = uploadfile.postedfile.contentlength;
imguploadedname = uploadfile.postedfile.filename;
byte[] imgbinarydata=new byte[imglen];
imgcontenttype = uploadfile.postedfile.contenttype;
imgname_value = imgname.value;
try
{
if(imgname_value.length < 1)
{
imgname_value = getlastrightof("//",imguploadedname );
}
}
catch(exception myex)
{
response.write(myex.message);
}
int n = imgstream.read(imgbinarydata, 0, imglen);
int numrowsaffected = mydatabasemethod(imgname_value, imgbinarydata, imgcontenttype);
if(numrowsaffected > 0)
response.write( "<br> uploaded image " );
else
response.write ( "<br> an error occurred uploading the image.d " );
}
public string getlastrightof(string lookfor,string mystring)
{
int strpos;
strpos = mystring.lastindexof(lookfor);
return mystring.substring(strpos + 1);
}
public int mydatabasemethod(string imgname,byte[] imgbin,string imgcontenttype)
{
sqlconnection connection = new sqlconnection(application["test_conn"].tostring());
string sql="insert into image (img_name,img_data,img_contenttype) values ( @img_name, @img_data,@img_contenttype )";
sqlcommand command=new sqlcommand ( sql,connection );
sqlparameter param0=new sqlparameter ( "@img_name", sqldbtype.varchar,50 );
param0.value = imgname;
command.parameters.add( param0 );
sqlparameter param1=new sqlparameter ( "@img_data", sqldbtype.image );
param1.value = imgbin;
command.parameters.add( param1 );
sqlparameter param2 =new sqlparameter ( "@img_contenttype", sqldbtype.varchar,50 );
param2.value = imgcontenttype;
command.parameters.add( param2 );
connection.open();
int numrowsaffected = command.executenonquery();
connection.close();
return numrowsaffected;
}
#region web form designer generated code
override protected void oninit(eventargs e)
{
//
// codegen：该调用是 asp.net web 窗体设计器所必需的。
//
initializecomponent();
base.oninit(e);
}
/// <summary>
/// 设计器支持所需的方法 - 不要使用代码编辑器修改
/// 此方法的内容。
/// </summary>
private void initializecomponent()
{
this.button1.click += new system.eventhandler(this.button1_click);
this.load += new system.eventhandler(this.page_load);
}
#endregion
}
}
------------------------------------------------------------
二、浏览图片：
imgvies.aspx文件：
<%@ page language="c#" codebehind="imgview.aspx.cs" autoeventwireup="false" inherits="study.uploadimage.imgview" %>
<!doctype html public "-//w3c//dtd html 4.0 transitional//en" >
<html>
<head>
<title>imgview</title>
<meta name="generator" content="microsoft visual studio 7.0">
<meta name="code_language" content="c#">
<meta name="vs_defaultclientscript" content="javascript">
<meta name="vs_targetschema" content="http://schemas.microsoft.com/intellisense/ie5">
</head>
<body ms_positioning="gridlayout">
</body>
</html>
codebehind文件：
using system;
using system.collections;
using system.componentmodel;
using system.data;
using system.drawing;
using system.web;
using system.web.sessionstate;
using system.web.ui;
using system.web.ui.webcontrols;
using system.web.ui.htmlcontrols;
using system.data.sqlclient;
namespace study.uploadimage
{
/// <summary>
/// imgview 的摘要说明。
/// </summary>
public class imgview : system.web.ui.page
{
private void page_load(object sender, system.eventargs e)
{
sqlconnection mydsn = new sqlconnection(application["test_conn"].tostring());
mydsn.open();
int imgid = int.parse(request.querystring["id"]);
string sqltext = "select img_name, img_data, img_contenttype from image where img_pk=" + imgid;
trace.write(sqltext);
sqlcommand mycommand = new sqlcommand (sqltext, mydsn);
sqldatareader dr =mycommand.executereader();
if(dr.read())
{
response.contenttype = (dr["img_contenttype"].tostring());
response.binarywrite((byte[])dr["img_data"]);
}
mydsn.close();
}
#region web form designer generated code
override protected void oninit(eventargs e)
{
//
// codegen：该调用是 asp.net web 窗体设计器所必需的。
//
initializecomponent();
base.oninit(e);
}
/// <summary>
/// 设计器支持所需的方法 - 不要使用代码编辑器修改
/// 此方法的内容。
/// </summary>
private void initializecomponent()
{
this.load += new system.eventhandler(this.page_load);
}
#endregion
}
}
这样这个程序就完成了，简单吧。当然还很多改进之处，希望大家多想想多编编一定可以写出更多的图象上传程序。
