使用IHttpHandler防盗链

using System; 

using System.Data; 

using System.Configuration; 

using System.Web; 

using System.Web.Security; 

using System.Web.UI; 

using System.Web.UI.WebControls; 

using System.Web.UI.WebControls.WebParts; 

using System.Web.UI.HtmlControls; 

public class myhandler : IHttpHandler 

{ 

public void ProcessRequest(HttpContext context) 

{ 

string FileName = context.Server.MapPath(context.Request.FilePath); 

if (context.Request.UrlReferrer.Host == null) 

{ 

context.Response.ContentType = "image/JPEG"; 

context.Response.WriteFile("~/images/no.png");//被替换图片 

 } 

else 

 { 

if (context.Request.UrlReferrer.Host.IndexOf("localhost") > -1)//这里是你的域名 

 { 

context.Response.ContentType = "image/JPEG"; 

context.Response.WriteFile(FileName); 

} 

else 

 { 

context.Response.ContentType = "image/JPEG"; 

context.Response.WriteFile("~/images/no.png"); 

} 

} 

} 

public bool IsReusable 

{ 

get { return true; } 

} 

public myhandler() 

{ 

} 

}