asp.net download Web page program showing download prompts

Web site production is often to develop the function of downloading files, the following three ways to download the file:


1, ASP implementation of the download code
<%


filename = request.querystring ("filename")


If filename = "" Then


Response.Write "Please enter filename parameter, specify download filename"


Else


Response.ContentType = "Application/octet-stream"


Response.AddHeader "content-disposition", "attachment;" filename = "& filename


Set FileStream = Server.CreateObject ("ADODB.stream")


Filestream.mode = 3


Filestream.type = 1


Filestream.open


Filestream.loadfromfile (Server.MapPath (filename))





Response.BinaryWrite (FileStream.Read)





filestream.close ()


Set FileStream = Nothing


End If


%> The above code into an ASP-type file, which is similar when used: Download.asp?filename=a.gif.


2, using WebClient
Add the following code in the Download button event


System.Net.WebClient WC = new System.Net.WebClient ();


WC. DownloadFile ("Http://localhost/a.gif", "c:a.gif");


The above code will put the server-side a.gif files in the absence of any hint to download the client's C disk, there is no hint or more frightening, but sometimes it is really necessary to do so. The code can also be run on a desktop program.



asp.net download Web page program showing download prompts
//Open the file to download


System.IO.FileStream r = new System.IO.FileStream (FileName, System.IO.FileMode.Open);


//Set basic information


Response.Buffer = false;


Response.AddHeader ("Connection", "keep-alive");


Response.ContentType = "Application/octet-stream";


Response.AddHeader ("Content-disposition", "attachment;filename=" + System.IO.Path.GetFileName (filename));


Response.AddHeader ("Content-length", r.length.tostring ());


         


while (true)


{


//Open buffer space


byte[] buffer = new byte[1024];


//Read the file data


int leng = r.read (buffer, 0, 1024);


if (leng = = 0)//To end of file, ending


break;


if (leng = = 1024)//read out file data length equals buffer length, write buffer data directly to


Response.BinaryWrite (buffer);


Else


            {


//read out file data is smaller than the buffer, redefine the buffer size, only to read the last block of data in the file


byte[] b = new Byte[leng];


for (int i = 0; i < Leng; i++)


B[i] = buffer[i];


Response.BinaryWrite (b);


            }


        }


r.close ()//close Download file


Response.End ()//end File Download


This method has the download prompt box, the server side may know when the download completes.