ASP.Net Transmit File - asp.net

I am writing a webapplication in ASP.net.
I am trying to make a file dialog box appear for downloading something off the server.
I have the appropriate file data stored in a variable called file.
File has fields:
FileType - The MIMEType of the file
FilePath - The server-side file path
Here's the code so far:
Response.Clear();
Response.ContentType = file.FileType;
Response.AppendHeader("Content-Disposition", "attachment; filename=" + GetFileName(file));
Response.TransmitFile(file.FilePath) ;
Response.End();
GetFileName is a function that gets me the filename from an attachment object. I only store the path.
The above code is in a function called "Download_Clicked" that is an event that triggers on click. The event is mapped to a LinkButton.
The problem is that when I run the above code, nothing happens. The standard dialog box does not appear.
I have attempted the standard trouble-shooting such as making sure the file exists, and ensuring the path is correct. They are both dead on the mark.
My guess is that because my machine is also the server, it may not be processing properly somehow.
Thanks in advance.
Edit 1: Attempted putting control onto another page, works fine.
Edit 2: Resolved issue by removing control from AJAX Update Panel.

I've found another to do this without removing the update panel. Place the code below in your page load and you'll now be able to use that button to trigger a download.
ScriptManager.GetCurrent(this.Page).RegisterPostBackControl(Button);

Use Response.WriteFile() instead.
Also, don't use Response.End()! This aborts the thread. Use Response.Flush(); Response.Close();

Try changing
Response.AppendHeader("Content-Disposition", "attachment; filename=" + GetFileName(file));
To
Response.AppendHeader("Content-Disposition", "attachment; filename=" + Path.GetFileName(GetFileName(file))));
If that doesn't work, you can always use Response.BinaryWrite or Resonse.Write to stream the file to the web browser
Here is how transmit the file using Response.Write or Response.BinaryWrite. Put these functions in a library somewhere then call them as needed
public void SendFileToBrowser(String FileName, String MIMEType, String FileData)
{
Response.Clear();
Response.AddHeader("Content-Disposition", "attachment; filename=" + FileName);
Response.ContentType = MIMEType;
Response.Buffer = true;
Response.Write(FileData);
Response.End();
}
public void SendFileToBrowser(String FileName, String MIMEType, Byte[] FileData)
{
Response.Clear();
Response.AddHeader("Content-Disposition", "attachment; filename=" + FileName);
Response.ContentType = MIMEType;
Response.Buffer = true;
Response.BinaryWrite(FileData);
Response.End();
}
Then somewhere you call these functions like so
SendFileToBrowser("FileName.txt", "text/plain", "Don't try this from an Update Panel. MSAjax does not like it when you mess with the response stream.");

See edit on initial post.
Removed Ajax Update Panel to resolve the error. The panel was stopping the post back to the server.
For more info, see Cris Valenzuela's comment.

Related

download code expalanation in asp.net

can anyone please explain this code
if (e.CommandName == "download")
{
string filename = e.CommandArgument.ToString();
string path = MapPath("~/Docfiles/" + filename);
byte[] bts = System.IO.File.ReadAllBytes(path);
Response.Clear();
Response.ClearHeaders();
Response.AddHeader("Content-Type", "Application/octet-stream");
Response.AddHeader("Content-Length", bts.Length.ToString());
Response.AddHeader("Content-Disposition", "attachment; filename=" + filename);
Response.BinaryWrite(bts);
Response.Flush();
Response.End();
}
what is command argument, mappath, and also what is this
"Content-Type", "Application/octet-stream"
and also
Response.AddHeader("Content-Length", bts.Length.ToString());
Response.AddHeader("Content-Disposition", "attachment; filename=" + filename);
Response.BinaryWrite(bts);
Response.Flush();
First, I advise you to use the MSDN documentation to search for more information about the objects and methods you wanna know more about. MSDN is a useful network and should be used.
Quoting the MSDN CommandArgument : "Gets or sets an optional parameter passed to the Command event along with the associated CommandName". It is used to get an parameter that was passed to the command event. In this case, it was the file name.
string filename = e.CommandArgument.ToString();
The MapPath is used to map a specified path to a physical path. Using this you get the real path of the file. For example: "C:\Docfiles\Yourfile.pdf"
string path = MapPath("~/Docfiles/" + filename);
The ReadAllBytes method, opens a file, reads the content and then closes the file. This return the content of this file as a byte array.
byte[] bts = System.IO.File.ReadAllBytes(path);
The Response object is used to send output to the user from the server.
Response.Clear();
Response.ClearHeaders();
Response.AddHeader is used to build the header of response that will be sent back to user. We use it to set infos about the data we are sending back to the client.
The "Content-Type" attribute is used to especify what kind of file you are returning to the user.
Response.AddHeader("Content-Type", "Application/octet-stream");
The "Content-Length" attribute is used to inform to the browser the size of the the file you are returning.
Response.AddHeader("Content-Length", bts.Length.ToString());
The "Content-Disposition" is used to inform the name of the file that will be returned. For example "file1.doc"
Response.AddHeader("Content-Disposition", "attachment; filename=" + filename);
The "BinaryWrite()" write your file (who, at this moment, is in a byte array format) to the current HTTP output without any character conversion.
Response.BinaryWrite(bts);
The Flush method sends buffered output immediately.
Response.Flush();
And, finally, causes the server to stop processing the request and return the current result.
Response.End();
If the command is download, most likely from a grid button, then get the name of the file as the argument (these are properties on a button control), and send it to the browser. This prompts the user to download the file.

Why cant opened downloaded docx files ,in asp.net?

I try to download a docx file from serverside.
What is my wrong ?
this is code :
FileInfo file = new FileInfo(filepath);
Response.Clear();
Response.ClearHeaders();
Response.ClearContent();
Response.AppendHeader("Content-Disposition", "attachment; filename = " + ((Button)sender).CommandName + ".docx");
Response.AppendHeader("Content-Length", file.Length.ToString());
Response.ContentType = "application/octet-stream";
Response.WriteFile(file.FullName);
Response.Flush();
Response.Close();
Response.End();
I have posted something similar in another question for an PDF but here goes. It's much easier to stream this sort of data back through an ASHX handler.
Something like what I posted in this question but with a docx file.
Display PDF in iframe
It looks like you are using a normal ASP.NET page and are trying to modify the standard behavior by clearing out the headers, etc. You won't have to fiddle with the headers or anything like that with an ashx handler.

Export a excel file witout any dialog+asp.net,c#

I am exporting a excel file from "c:Test\data.xls" using the responce object
like:
response.AddHeader("Content-Disposition", "attachment; filename=" + FileName + ";");
it is opening a dialog box.But Now we don't need the dialog box.we want to directly open file without dialog.
Can any body help me out
use
response.AddHeader("Content-Disposition", "inline; filename=" + FileName + ";");
Whether it opens directly depends on client-side security settings to this might work but there is no guarantee...
Instead of attaching file to response you nee write it's content to response stream.
//Set the appropriate ContentType.
Response.ContentType = "application/vnd.ms-excel"; // not sure in content type
//Get the physical path to the file.
string filePath = #"c:Test\data.xls";
//Write the file directly to the HTTP content output stream.
Response.WriteFile(filePath);
Response.End();
But also it depeneds on the client side settings.

How to send a file to a client so a Download dialog will open?

I have a file, say a PDF on my website and when a user visits a page I want to display a download dialog for the pdf on page load or a button click.
I did a google search and I found two ways to do this but wondering what is the accepted way of doing this? I am currently doing this
string pdfPath = MapPath("mypdf.pdf");
Response.ContentType = "Application/pdf";
Response.AppendHeader( "content-disposition",
"attachment; filename=" + name );
Response.WriteFile(pdfPath);
Response.End();
(Code was based off code from http://aspalliance.com/259, also found code from
http://www.west-wind.com/weblog/posts/76293.aspx)
Your code, will display the file to the user perfectly. But they will have to use the "Save As" option to actually save it.
If you wish to present the "Save Dialog" to the user, try the following:
string pdfPath = MapPath("mypdf.pdf");
Response.ContentType = "Application/pdf";
Response.AppendHeader("content-disposition",
"attachment; filename=" + pdfPath );
Response.TransmitFile(pdfPath);
Response.End();
This of course assumes the file actually exists on the server and is not being dynamically generated.
This code will Send Any file to directly on client Browser
Response.ContentType = "application/pdf";
Response.WriteFile(PathToFile);
Response.Flush();

How can I get the user response regarding SaveFileDialog in Javascript?

The following code is implemented in Page_Load event to show SaveFileDialog to the user
string targetFileName = Request.PhysicalApplicationPath + "Reports\\TempReports\\FolderMasters" + Utility.GetRandomNumber() + ".pdf";
FileInfo file = new FileInfo(targetFileName);
// Clear the content of the response.
Response.ClearContent();
Response.AddHeader("Content-Disposition", "attachment; filename=" + file.Name);
Response.AddHeader("Content-Length", file.Length.ToString());
Response.ContentType = "application/pdf";
Response.TransmitFile(file.FullName);
Response.End();
How can I get the user response to SaveFileDialog, as I need to know user response to this dialog?
Also, is there something wrong with these lines of code, as I had the following exception
"Unable to evaluate expression because the code is optimized or a native frame is on top of the call stack."
You can't get the user response to SaveFileDialog as all file-events have been blocked for browser-javascript as it could be a very big security-hole ...
I'm here again, as I got a solution for my second question.
For Response.End, call the HttpContext.Current.ApplicationInstance.CompleteRequest method instead of Response.End to bypass the code execution to the Application_EndRequest event.
Have look ...

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