ashx文件的使用(转)

Handler.ashx：
<%@ WebHandler Language="C#" class="Handler" %>
using System;
using System.IO;
using System.Web;
public class Handler : IHttpHandler {

 

public bool IsReusable {
get {
return true;
}
}
public void ProcessRequest (HttpContext context) {
context.Response.ContentType = "image/jpeg";
context.Response.Cache.SetCacheability(HttpCacheability.Public);
context.Response.BufferOutput = false;
PhotoSize size;
switch (context.Request.QueryString["Size"]) {
case "S":
size = PhotoSize.Small;
break;
case "M":
size = PhotoSize.Medium;
break;
case "L":
size = PhotoSize.Large;
break;
default:
size = PhotoSize.Original;
break;
}
Int32 id = -1;
Stream stream = null;
if (context.Request.QueryString["PhotoID"] != null && context.Request.QueryString["PhotoID"] != "") {
id = Convert.ToInt32(context.Request.QueryString["PhotoID"]);
stream = PhotoManager.GetPhoto(id, size);
} else {
id = Convert.ToInt32(context.Request.QueryString["AlbumID"]);
stream = PhotoManager.GetFirstPhoto(id, size);
}
if (stream == null) stream = PhotoManager.GetPhoto(size);
const int buffersize = 1024 * 16;
byte[] buffer = new byte[buffersize];
int count = stream.Read(buffer, 0, buffersize);
while (count > 0) {
context.Response.OutputStream.Write(buffer, 0, count);
count = stream.Read(buffer, 0, buffersize);
}
}
}

 

*.aspx:
<img src="myHttpHander.ashx?id=123" width="20" height="20" />

 

我们变通以下，发现其实除了可以输出图片以外，还可以输出文字：
Handler.ashx：
<%@ WebHandler Language="C#" class="Handler" %>
using System;
using System.Web;
public class Handler : IHttpHandler {

public void ProcessRequest (HttpContext context) {
context.Response.ContentType = "text/plain";
context.Response.Write("alert('hi')");
}

public bool IsReusable {
get {
return false;
}
}
}

 

*.aspx:
弹出alert
<script src="Handler.ashx"></script>
也可以把.ashx当成css文件
<link href="css/Handler.ashx" rel="stylesheet" type="text/css">
xml文件
orderDoc.load("Handler.ashx");

 

还可以嵌入文字：
Handler.ashx：
<%@ WebHandler Language="C#" class="TestHandler" %>
using System;
using System.Web;
public class TestHandler : IHttpHandler {

public void ProcessRequest (HttpContext context) {
context.Response.ContentType = "text/plain";
context.Response.Write("document.write("Hello World");");
}

 

public bool IsReusable {
get {
return false;
}
}
}
*.aspx:
<script type="text/javascript" src="TestHandler.ashx" />

 

当你希望从ashx或HttpHandler里访问你的Session时,你必须实现IReadOnlySessionState接口.

代码:

using System;
using System.Web;
using System.Web.SessionState;

public class DownloadHandler : IHttpHandler, IReadOnlySessionState
{
public bool IsReusable { get { return true; } }

public void ProcessRequest(HttpContext ctx)
{
ctx.Response.Write(ctx.Session["fred"]);
}
}