Asp. NET Notes HttpHandler Operational Details _ Practical skills

1, HttpHandler

Example 1: By generating a dynamic picture output the client's IP address, operating system type, browser type

Copy Code code as follows:

<%@ WebHandler language= "C #" class= "Visitor"%>

Using System;
Using System.Web;

public class Visitor:ihttphandler {

public void ProcessRequest (HttpContext context)
{
Context. Response.ContentType = "Image/jpeg";
using (System.Drawing.Bitmap bitimage = new System.Drawing.Bitmap (330, 300))
{
Set Canvas
using (System.Drawing.Graphics g = System.Drawing.Graphics.FromImage (Bitimage))
{
Ip
g.DrawString ("IP:" + context.) Request.userhostaddress, New System.Drawing.Font ("XXFarEastFont-Arial"), System.Drawing.Brushes.Red, new System.Drawing.PointF (0, 0));
Operating system
g.DrawString ("Operating system:" + context.) Request.Browser.Platform, New System.Drawing.Font ("XXFarEastFont-Arial"), System.Drawing.Brushes.Red, new System.Drawing.PointF (0 , 50));
Browser
g.DrawString ("Browser:" + context.) Request.Browser.Type, New System.Drawing.Font ("XXFarEastFont-Arial"), System.Drawing.Brushes.Red, new System.Drawing.PointF (0, 100 ));
}
Save to the output stream
Bitimage.save (context. Response.outputstream, System.Drawing.Imaging.ImageFormat.Jpeg);

}
}

public bool IsReusable {
get {
return false;
}
}

}

Example 2: Through the "Download" Connection, pop-up user attachment save

HTML code: <a href= "dowload.ashx" > Download </a>

Copy Code code as follows:

<%@ WebHandler language= "C #" class= "Dowload"%>

Using System;
Using System.Web;

public class Dowload:ihttphandler {

public void ProcessRequest (HttpContext context)
{
String fileName = Httputility.urlencode ("tragic. jpg");
Context. Response.ContentType = "Image/jpeg";

Open the Attachment dialog box header header and set its value
Context. Response.AddHeader ("Content-disposition", "attachment:filename=" + filename);
Context. Response.WriteFile ("apple. jpg");
}

public bool IsReusable {
get {
return false;
}
}

}