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


答案：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
复制代码 代码如下:
 
<%@ 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 
// AddShuiYinPi
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