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asp.net UpdatePanel实现无刷新上传图片

1）前台
复制代码 代码如下:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!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">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Button" />
<asp:FileUpload ID="File1" runat="server" Width="200px" />
</ContentTemplate>
<Triggers>
<asp:PostBackTrigger ControlID="Button1" />
</Triggers>
</asp:UpdatePanel>
<asp:Image id="image1" ImageUrl="http://images.cnblogs.com/nopic.gif" Height="115px" Width="108px" runat="server"/>
</div>
</form>
</body>
</html>

2）后台
复制代码 代码如下:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
using System.Data.SqlClient;
using System.Data;
public partial class _Default:baseClass
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
HttpPostedFile upFile = File1.PostedFile;
int iFileLength = upFile.ContentLength;
try
{
if (iFileLength == 0)
{
MessageBox("请选择要上传的文件！");
}
else
{
Byte[] FileByteArray = new Byte[iFileLength];
Stream StreamObject = upFile.InputStream;
StreamObject.Read(FileByteArray, 0, iFileLength);
SqlConnection conn = new SqlConnection("server=.;database=Test;uid=sa;pwd=1234;");
ExecuteBySQLNonQuery("delete from imageTable");
SqlCommand cmd = new SqlCommand("insert into [imageTable] values(@image)", conn);
cmd.Parameters.Add("@Image", SqlDbType.Binary, iFileLength).Value = FileByteArray;
conn.Open();
cmd.ExecuteNonQuery();
conn.Close();
MessageBox("已经成功上传了照片!");
}
image1.ImageUrl = "displayempphoto.ashx";
}
catch (Exception ex)
{
MessageBox(ex.Message);
}
}
}

3）建立一般处理文件displayempphoto.ashx
复制代码 代码如下:

<%@ WebHandler Language="C#" Class="DisplayEmpPhoto" %>
using System;
using System.Web;
using System.Data.SqlClient;
using System.Web.Configuration;
using System.Data;
public class DisplayEmpPhoto : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
using (SqlConnection cn = new SqlConnection(WebConfigurationManager.ConnectionStrings["CONNECTIONSQL"].ConnectionString))
{
SqlCommand SQLCmd = cn.CreateCommand();
SQLCmd.CommandText = "SELECT imagedata FROM imageTable";
cn.Open();
using (SqlDataReader dr = SQLCmd.ExecuteReader(CommandBehavior.SingleRow))
{
if (dr.Read())
{
// 改变 HTTP 文件头的输出格式，以便让浏览器知道所输出的文件格式是 JPEG 图文件 。
context.Response.ContentType = "Image/JPEG";
context.Response.Clear();
context.Response.BufferOutput = true;
context.Response.BinaryWrite(dr.GetSqlBytes(0).Value);
}
}
}
}
public bool IsReusable
{
get
{
return false;
}
}
}