asp.net 自定义控件实现无刷新上传图片,立即显示缩略图,保存图片缩略图

更新时间：2010年01月01日 00:04:31 作者：

自定义控件实现无刷新上传图片,立即显示缩略图,保存图片缩略图

如图:

点击浏览,选择图片之后,右面显示图片

第一步:

创建CtFileUpLoad.ascx

 
<%@ Control Language="C#" AutoEventWireup="true" CodeFile="CtFileUpLoad.ascx.cs" 
Inherits="WebParts_CtFileUpLoad" %> 
<table cellpadding="0" cellspacing="0"> 
<tr> 
<td> 
<iframe src="/WebParts/FileUpLoad.aspx?<%=ParsValue %>" width="240px" height="22px" frameborder="0" scrolling="no"></iframe> 
</td> 
<td> 
<asp:TextBox runat="server" ID="tbFileName" style="display:none"></asp:TextBox> 
<div id="dvImg" runat="server" style="position:absolute; margin-left:50px;"> 
</div> 
</td> 
</tr> 
</table> 
<script language="javascript"> 
function <%=ClientID %>CallLoaded() 
{ 
<% =OnLoaded %>; 
} 
</script> 

复制代码代码如下:

 
using System; 
using System.Collections; 
using System.Configuration; 
using System.Data; 
using System.Web; 
using System.Web.Security; 
using System.Web.UI; 
using System.Web.UI.HtmlControls; 
using System.Web.UI.WebControls; 
using System.Web.UI.WebControls.WebParts; 
using System.Drawing; 
public partial class WebParts_CtFileUpLoad : System.Web.UI.UserControl 
{ 
public bool AutoFileName 
{ 
get 
{ 
object ob = ViewState[ClientID + "AutoFileName"]; 
if (ob == null) 
ob = true; 
return (bool)ob; 
} 
set 
{ 
ViewState[ClientID + "AutoFileName"] = value; 
} 
} 
public string UpLoadPath 
{ 
get 
{ 
object ob = ViewState[ClientID + "UpLoadPath"]; 
if (ob == null) 
ob = "UPLOADFILES"; 
return ob.ToString(); 
} 
set 
{ 
ViewState[ClientID + "UpLoadPath"] = value; 
} 
} 
public string OnLoaded 
{ 
get 
{ 
object ob = ViewState[ClientID + "OnLoaded"]; 
if (ob == null) 
ob = ""; 
return ob.ToString(); 
} 
set 
{ 
ViewState[ClientID + "OnLoaded"] = value; 
} 
} 
public string SupportExtension 
{ 
get 
{ 
object ob = ViewState[ClientID + "SupportExtension"]; 
if (ob == null) 
{ 
ob = "gif|png|jpeg|jpg"; 
} 
return ob.ToString(); 
} 
set 
{ 
ViewState[ClientID + "SupportExtension"] = value.Replace(".", ""); 
} 
} 
public bool ShowImg 
{ 
get 
{ 
object ob = ViewState[ClientID + "ShowImg"]; 
if (ob == null) 
ob = true; 
return (bool)ob; 
} 
set 
{ 
if ((bool)value) 
dvImg.Style["display"] = "block"; 
else 
dvImg.Style["display"] = "none"; 
} 
} 
public string FileName 
{ 
get 
{ 
return tbFileName.Text; 
} 
} 
protected string ParsValue = ""; 
protected void Page_Load(object sender, EventArgs e) 
{ 
ParsValue = "AutoFileName=" + AutoFileName.ToString() + "&SupportExtension=" + SupportExtension + "&UpLoadPath=" + UpLoadPath 
+ "&ID=" + ClientID; 
} 
} 

第二步:
创建FileUpLoad.aspx

复制代码代码如下:

 
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="FileUpLoad.aspx.cs" Inherits="WebParts_FileUpLoad" %> 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 
<html xmlns="http://www.w3.org/1999/xhtml"> 
<head runat="server"> 
</head> 
<body style="margin:0px;"> 
<form id="form1" runat="server"> 
<div> 
<asp:FileUpload runat="server" ID="FileUpload1" onchange="upload(this);" /> 
<asp:Button runat="server" ID="btUp" style="display:none" OnClick="btUp_Click" /> 
</div> 
</form> 
</body> 
</html> 
<script language="javascript"> 
function upload(ob) 
{ 
var expStr=/.*(<%=SupportExtension%>)$/i; 
if(!expStr.test(ob.value)) 
{ 
alert("上传文件类型有误。\n(支持文件类型：<%=SupportExtension%>)"); 
} 
else 
{ 
var btUp=document.getElementById("<%=btUp.ClientID %>"); 
btUp.click(); 
} 
} 
</script> 

复制代码代码如下:

 
using System; 
using System.Collections; 
using System.Configuration; 
using System.Data; 
using System.Web; 
using System.Web.Security; 
using System.Web.UI; 
using System.Web.UI.HtmlControls; 
using System.Web.UI.WebControls; 
using System.Web.UI.WebControls.WebParts; 
using System.Drawing; 
using System.IO; 
public partial class WebParts_FileUpLoad : System.Web.UI.Page 
{ 
protected string SupportExtension = ""; 
protected string UpLoadPath = ""; 
protected bool AutoFileName; 
protected string ParentID = ""; 
protected void Page_Load(object sender, EventArgs e) 
{ 
SupportExtension = Request.QueryString["SupportExtension"]; 
UpLoadPath = Request.QueryString["UpLoadPath"]; 
AutoFileName = bool.Parse(Request.QueryString["AutoFileName"].ToString()); 
ParentID = Request.QueryString["ID"].ToString(); 
} 
protected void btUp_Click(object sender, EventArgs e) 
{ 
Boolean fileOK = false; 
if (FileUpload1.HasFile) 
{ 
String fileExtension = 
System.IO.Path.GetExtension(FileUpload1.FileName).ToLower(); 
String[] allowedExtensions = SupportExtension.Split(new string[] { "|" }, StringSplitOptions.RemoveEmptyEntries); 
for (int i = 0; i < allowedExtensions.Length; i++) 
{ 
if (fileExtension == "." + allowedExtensions[i]) 
{ 
fileOK = true; 
} 
} 
if (fileOK) 
{ 
string path = ""; 
string name = ""; 
string sPath = ""; 
if (AutoFileName) 
{ 
name = DateTime.Now.Ticks.ToString() + System.IO.Path.GetExtension(FileUpload1.FileName).ToLower(); 
} 
else 
{ 
name = FileUpload1.FileName; 
} 
sPath = Request.PhysicalApplicationPath + "\\" + UpLoadPath + "\\"; 
path = sPath + name; //图片地址 
string fileName = name; //文件名 
string fileName_s = "s_" + name; //缩略图文件名称 
try 
{ 
//FileInfo file = new FileInfo(name); 
// string fileContentType = FileUpload1.PostedFile.ContentType; 
//string name = FileUpload1.PostedFile.FileName;//客户端文件路径 
//string fileName_sy = "sy_" + file.Name; //水印图文件名称(文字) 
//string fileName_syp = "syp_" + file.Name;//水印图文件名称(图片) 
//string webFilePath = Server.MapPath(UpLoadPath + "\\" + fileName); 
//string webFilePath_s = Server.MapPath(UpLoadPath + "\\" + fileName_s); 
string webFilePath = sPath + fileName;//服务器端文件路径 
string webFilePath_s = sPath + fileName_s;//服务器端缩略图路径 

if (!File.Exists(webFilePath)) 
{ 
if (FileUpload1.PostedFile.ContentLength < 2 * 1024 * 1024) //如果图片小于2M 
{ 
try 
{ 
FileUpload1.SaveAs(path); //使用saveAS方法保存文件 
System.Drawing.Image image = System.Drawing.Image.FromFile(path); 
if (image.Width > 800 || image.Height > 600) 
{ 
MakeThumbnail(webFilePath, webFilePath_s, 800, 600, "W");//生成缩略图的方法 
} 
else 
{ 
MakeThumbnail(webFilePath, webFilePath_s, 300, 230, "W");//生成缩略图的方法 
} 
image.Dispose(); 
// AddShuiYinWord(webFilePath, webFilePath_sy); //保存水印文字图片 
// AddShuiYinPic(webFilePath, webFilePath_syp, webFilePath_sypf);//保存添加水印图片之后的图片 
//MakeThumbnail(webFilePath, webFilePath_s, 400, 300, "W");//生成缩略图的方法 

Page.RegisterClientScriptBlock("succcess", @"<script> 
alert('上传成功'); 
parent.document.getElementById('" + ParentID + "_" + "tbFileName" + @"').value='" + fileName_s + @"'; 
</script>"); 
} 
catch (Exception ex) 
{ 
Page.RegisterClientScriptBlock("err", "<script>alert('提示：文件上传失败，失败原因：：" + ex.Message + "');</script>"); 
} 
} 
else 
{ 
Page.RegisterClientScriptBlock("err", "<script>alert('提示：图片不能大于2M');</script>"); 
} 
} 
else 
{ 
this.Page.RegisterClientScriptBlock("err", "<script>alert('图片重复');</script>"); 
} 
} 
catch (System.Exception err) 
{ 
this.Page.RegisterClientScriptBlock("err", "<script>alert('" + err.Message + "');</script>"); 
} 
try 
{ 
Bitmap bmp = new Bitmap(path); 
int width = 0, height = 0; 
int dvalue = 200; 
if (bmp.Width < dvalue & bmp.Height < 200) 
{ 
width = bmp.Width; 
height = bmp.Height; 
} 
else if (bmp.Width > bmp.Height) 
{ 
width = dvalue; 
height = dvalue * (bmp.Width / bmp.Height); 
} 
else 
{ 
height = dvalue; 
width = dvalue * (bmp.Height / bmp.Width); 
} 
this.Page.RegisterClientScriptBlock("show", @"<script> 
parent.VarValue='" + UpLoadPath + "/" + fileName_s + "';" + 
"parent." + ParentID + "CallLoaded();" + 
"parent.document.getElementById('" + ParentID + "_" + "dvImg" + @"').innerHTML=""" + 
"<img src='https://www.jb51.net/" + UpLoadPath + "/" + fileName_s + "' style='width:" + width.ToString() + "px; height:" + height + "px;'/>" + @"""; 
</script>"); 
bmp.Dispose(); 
} 
catch 
{ 
} 
finally 
{ 
//****判断该文件是否存在,如果存在,则删除图片 
if (File.Exists(path)) 
{ 
//****删除用户客户端上传的图片,服务器上只保存缩略之后的图片 
File.Delete(path); 
} 
} 
} 
else 
{ 
this.Page.RegisterClientScriptBlock("err", "<script>alert('error');</script>"); 
} 
} 
} 
/// <summary> 
/// 生成缩略图 
/// </summary> 
/// <param name="originalImagePath">源图路径（物理路径）</param> 
/// <param name="thumbnailPath">缩略图路径（物理路径）</param> 
/// <param name="width">缩略图宽度</param> 
/// <param name="height">缩略图高度</param> 
/// <param name="mode">生成缩略图的方式</param> 
public void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode) 
{ 
System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath); 
int towidth = width; 
int toheight = height; 
int x = 0; 
int y = 0; 
int ow = originalImage.Width; 
int oh = originalImage.Height; 
switch (mode) 
{ 
case "HW"://指定高宽缩放（可能变形） 
break; 
case "W"://指定宽，高按比例 
toheight = originalImage.Height * width / originalImage.Width; 
break; 
case "H"://指定高，宽按比例 
towidth = originalImage.Width * height / originalImage.Height; 
break; 
case "Cut"://指定高宽裁减（不变形） 
if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight) 
{ 
oh = originalImage.Height; 
ow = originalImage.Height * towidth / toheight; 
y = 0; 
x = (originalImage.Width - ow) / 2; 
} 
else 
{ 
ow = originalImage.Width; 
oh = originalImage.Width * height / towidth; 
x = 0; 
y = (originalImage.Height - oh) / 2; 
} 
break; 
default: 
break; 
} 
//新建一个bmp图片 
System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight); 
//新建一个画板 
System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap); 
//设置高质量插值法 
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High; 
//设置高质量,低速度呈现平滑程度 
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality; 
//清空画布并以透明背景色填充 
g.Clear(System.Drawing.Color.Transparent); 
//在指定位置并且按指定大小绘制原图片的指定部分 
g.DrawImage(originalImage, new System.Drawing.Rectangle(0, 0, towidth, toheight), 
new System.Drawing.Rectangle(x, y, ow, oh), 
System.Drawing.GraphicsUnit.Pixel); 
try 
{ 
//以jpg格式保存缩略图 
bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg); 
} 
catch (System.Exception e) 
{ 
throw e; 
} 
finally 
{ 
originalImage.Dispose(); 
bitmap.Dispose(); 
g.Dispose(); 
} 
} 
/// <summary> 
/// 在图片上增加文字水印 
/// </summary> 
/// <param name="Path">原服务器图片路径</param> 
/// <param name="Path_sy">生成的带文字水印的图片路径</param> 
protected void AddShuiYinWord(string Path, string Path_sy) 
{ 
string addText = "https://www.jb51.net"; 
System.Drawing.Image image = System.Drawing.Image.FromFile(Path); 
System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image); 
g.DrawImage(image, 0, 0, image.Width, image.Height); 
System.Drawing.Font f = new System.Drawing.Font("Verdana", 16); 
System.Drawing.Brush b = new System.Drawing.SolidBrush(System.Drawing.Color.Blue); 
g.DrawString(addText, f, b, 15, 15); 
g.Dispose(); 
image.Save(Path_sy); 
image.Dispose(); 
} 
/// <summary> 
/// 在图片上生成图片水印 
/// </summary> 
/// <param name="Path">原服务器图片路径</param> 
/// <param name="Path_syp">生成的带图片水印的图片路径</param> 
/// <param name="Path_sypf">水印图片路径</param> 
protected void AddShuiYinPic(string Path, string Path_syp, string Path_sypf) 
{ 
System.Drawing.Image image = System.Drawing.Image.FromFile(Path); 
System.Drawing.Image copyImage = System.Drawing.Image.FromFile(Path_sypf); 
System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image); 
g.DrawImage(copyImage, new System.Drawing.Rectangle(image.Width - copyImage.Width, image.Height - copyImage.Height, copyImage.Width, copyImage.Height), 0, 0, copyImage.Width, copyImage.Height, System.Drawing.GraphicsUnit.Pixel); 
g.Dispose(); 
image.Save(Path_syp); 
image.Dispose(); 
} 
} 

属性:
SupportExtension 自定义上传的格式,用"|"分隔;
UpLoadPath 　　自定义上传到服务器的文件夹;
AutoFileName　　ture表示根据时间自动生成文件名,不会重复,false表示原来的图片名称,重复会覆盖.

转载请注明出处
2009-12-24 18:39:27 by 齐学佳

您可能感兴趣的文章:

asp.net repeater实现批量删除时注册多选框id到客户端
repeater批量删除时注册多选框id到客户端的实现代码
2008-11-11
Asp.net实现无刷新调用后台实体类数据并以Json格式返回
本文主要分享了Asp.net实现无刷新调用后台实体类数据并以Json格式返回的具体实例方法，具有一定的参考价值，有需要的朋友可以看下
2016-12-12
.NET Core配置多环境的方法步骤
配置多环境是日常开发经常需要用到的操作，实现多环境配置后可以规避生产测试环境混合带来的麻烦和风险，这篇文章主要介绍了.NET Core配置多环境的方法步骤，感兴趣的小伙伴们可以参考一下
2019-03-03
二级域名Cookie问题的解决方法
今天博客园全面采用二级域名后，发现即使用户已经登录，但在访问二级域名Blog页面时都显示没有登录(表现为发表评论时要求输入验证码, 收藏功能无法正常使用)，再次登录后，进入其他二级域名还是需要登录。
2008-10-10
asp.net core 集成swagger ui的原理解析
本文主要讲解了如何对API进行分组，这里仅仅是举了一个按照API功能进行分组的例子，其实在实际开发中，要按照何种方式分组，可以按照需求灵活定义，比如按照API版本进行分组
2021-10-10
asp.net URL重写简化版速学URL重写
asp.net URL重写（URLRewriter）简化版。速学URL重写
2010-01-01
Web.config(应用程序的配置信息)总结
Web.config文件是一个XML文本文件，它用来储存 ASP.NET Web 应用程序的配置信息（如最常用的设置ASP.NET Web 应用程序的身份验证方式），它可以出现在应用程序的每一个目录中,接下来详细介绍一下配置情况，感兴趣的朋友可以了解下
2013-01-01
ASP.NET调用WebService服务的方法详解
这篇文章主要介绍了ASP.NET调用WebService服务的方法,较为详细的分析了WebService服务的功能,创建步骤与使用方法,需要的朋友可以参考下
2016-05-05
使用.NET中的Action及Func泛型委托深入剖析
委托，在C#编程中占有极其重要的地位，委托可以将函数封装到委托对象中，并且多个委托可以合并为一个委托，委托对象则可以像普通对象一样被存储、传递，之后在任何时刻进行调用，因此，C#中函数回调机制的实现基本上依赖于委托,感兴趣的朋友可以参考下
2012-12-12
visual studio 2012安装配置方法图文教程附opencv配置教程
这篇文章主要为大家分享了visual studio 2012安装配置方法图文教程，文中附opencv配置教程，文中安装步骤介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们可以参考一下
2016-05-05