Responding with a csv file in asp.net - asp.net

I am trying to make a csv file from a textbox and then send it to the user. This is my code so far:
Response.Clear();
Response.ContentType = "text/csv";
Response.AppendHeader("Content-Disposition",
string.Format("attachment; filename={0}", DateTime.Now));
Response.Write(TextBox_Data.Text);
Context.Response.End();
What is sent is an empty xml file, I have never tried responding with a file before and I'm wondering why it does this?
I have also tried the following which did not work:
var writer = File.CreateText("C:\\file.csv");
writer.WriteLine(TextBox_Data.Text);
Context.Response.Clear();
Context.Response.AppendHeader("content-disposition", "attachment; filename=" + DateTime.Now + ".csv");
Context.Response.ContentType = "text/csv";
Context.Response.Write("C:\\file.csv");
Context.Response.Flush();
Context.Response.End();
Let me know if you have the answer :)

The following code worked for me. You may just be missing a file extension.
Response.Clear();
Response.ContentType = "text/csv";
Response.AppendHeader("Content-Disposition",
string.Format("attachment; filename={0}.csv", DateTime.Now));
Response.Write(TextBox_Data.Text);
Context.Response.End();

Just a complement on joshb's answer regarding the use of Response.End():
MSDN does not recommend the use of Response.End() for non-error cases, and in some cases it can actually cause the client to lose some data .
In my case sometimes the downloaded csv would loose the last bytes of the last line, so I removed the Response.End() and used
HttpContext.Current.ApplicationInstance.CompleteRequest()
instead, and I had to override the page's Render(HtmlTextWriter writer) method to not write anything on the request, since the csv was already writen.
public class PageBase : Page
{
private bool performRegularPageRender = true;
protected override void Render(HtmlTextWriter writer)
{
if (performRegularPageRender)
base.Render(writer);
}
public void SkipRegularPageRendering()
{
performRegularPageRender = false;
}
}
More info / credits:
msdn blog; Is Response.End() considered harmful?; PostBack and Render Solutions? Overrides

Related

How to let user select the location for downloading a file in asp.net?? To be precise a open file dialog equivalent in asp(Not fileUpload)

I am downloading a pdf file in my project. I want to let the user decide where to download the File. Quick help is helpful.
Thanks
try this:
It will display a dialog box in the browser and the user will select on where to save the file
protected void DownloadFile_Click(object sender, EventArgs e)
{
String Filepath;
System.IO.FileInfo file = new System.IO.FileInfo(Filepath); // full file path on disk
Response.ClearContent(); // Clear previous content
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();
}
You haven't specified how your application is serving this PDF file, but assuming that you have some WebForm which is streaming it to the Response, you should set the Content-Disposition header as attachment in order to force the Save As dialog in the browser.
For example:
protected void Download(object sender, EventArgs e)
{
Response.ContentType = "application/pdf";
Response.AddHeader("Content-Disposition", "attachment; filename=example.pdf");
Response.WriteFile(#"c:\work\example.pdf");
}

How to flush xml file in asp.net?

I want to return a xml file to a client, and THEN perform my logic.
I try to use Response.Flush(), but it doesn't work correctly for me.
My code:
protected void Page_Load(object sender, EventArgs e)
{
string arg1= this.Request["arg1"];
string arg2= this.Request["arg2"];
string arg3= this.Request["arg3"];
var doc = new XmlDocument();
XmlNode responseNode = doc.CreateElement("response");
doc.AppendChild(responseNode);
var messageNode = responseNode.AppendChild(doc.CreateElement("message"));
messageNode.InnerText = "Your request is being processed";
Response.Clear();
Response.ContentType = "text/xml";
Response.ContentEncoding = System.Text.Encoding.UTF8;
doc.Save(Response.Output);
Response.Flush(); // I want to display xml in this moment but it doesn't work
LogicManager manager = new LogicManager();
manager.DoSth(arg1, arg2, arg3);
Response.End();
}
Response.End();
Generally, it is a bad idea to be using Response.End() in your code.
From the source: This method is provided only for compatibility with ASP—that is, for compatibility with COM-based Web-programming technology that preceded ASP.NET. If you want to jump ahead to the EndRequest event and send a response to the client, it is usually preferable to call CompleteRequest instead.
Given this info, instead of this:
Response.Flush(); // I want to display xml in this moment but it doesn't work
LogicManager manager = new LogicManager();
manager.DoSth(arg1, arg2, arg3);
Response.End();
do this:
Response.Flush(); // I want to display xml in this moment but it doesn't work
Response.CompleteRequest();
LogicManager manager = new LogicManager();
manager.DoSth(arg1, arg2, arg3);
// here you might want to make sure that no other page handlers are executed

File Download inside iframe

I'm using following method to download a file.on a button click inside a iframe.it's working fine in every browser except IE.can some one plz suggest me a sollution
private void DownloadToBrowser(string filePath)
{
try
{
FileInfo file = new FileInfo(filePath);
Context.Response.Clear();
Context.Response.ClearHeaders();
Context.Response.ClearContent();
Context.Response.AddHeader("Content-Disposition", "attachment; filename=" + file.Name);
Context.Response.AddHeader("Content-Length", file.Length.ToString());
Context.Response.ContentType = "text/plain";
Context.Response.Flush();
Context.Response.TransmitFile(file.FullName);
Context.Response.End();
}
catch (Exception ex)
{
throw ex;
}
}
I would suggest removing the Context.Response.Flush(); line... I don't think it's necessary (as it will happen as part of Context.Response.End(); line), and maybe messing up how the browser receives the file on the next line.
Also, is the file you're transmitting definitely a plain-text file? If not, you'll need to provide a different Context.Response.ContentType();
You have most probably missed some HTTP response headers required by IE.
There is KB on microsoft web.
Also take a look at similar question on SO : PHP script to download file not working in IE
You could try something like this :
Context.Response.Buffer = true;
Context.Response.ContentType = "application/pdf";
Context.Response.AddHeader("Content-Disposition", "attachment;filename=" + FileName );
Context.Response.OutputStream.Write(dataBytes ,0,FileContentLength);
Also try adding this to your aspx page :
<%# Page aspCompat="True" other attributes %>
For Understanding I m using Dataset,
For download as a Excel File
Use Namespace:
using System.IO;
using System.Data;
DataSet ds = new DataSet("Table");
ds.Tables.Add("Table1");
ds.Tables[0].Columns.Add("Field1");
ds.Tables[0].Columns.Add("Field2");
ds.Tables[0].Columns.Add("Field3");
ds.Tables[0].Rows.Add();
ds.Tables[0].Rows[0][0] = "1";
ds.Tables[0].Rows[0][1] = "2";
ds.Tables[0].Rows[0][2] = "3";
HttpResponse response = HttpContext.Current.Response;
// first let's clean up the response.object
response.Clear();
response.Charset = "";
// set the response mime type for excel
response.ContentType = "application/vnd.ms-excel";
response.AddHeader("Content-Disposition", "attachment;filename=sample.xls");
// create a string writer
using (StringWriter sw = new StringWriter())
{
using (HtmlTextWriter htw = new HtmlTextWriter(sw))
{
// instantiate a datagrid
DataGrid dg = new DataGrid();
dg.DataSource = ds.Tables[0];
dg.DataBind();
dg.RenderControl(htw);
response.Write(sw.ToString());
response.End();
}
}
For Download as a Word File
Replace
response.ContentType = "application/msword";
response.AddHeader("Content-Disposition", "attachment;filename=sample.doc");

Download a string as a file in ASP.NET

The following method, based on code in this question, shows a file download dialog box in the browser, but then the download never starts (it stays at 0%):
protected void lnkExport_Click(object sender, EventArgs e) {
var bytes = Encoding.ASCII.GetBytes(SelectRecords()); //Data to be downloaded
Response.Clear();
Response.ContentType = "application/vnd.ms-excel";
Response.AddHeader("Content-Disposition", "attachment; filename=\"test.xls\"");
using (var stream = new MemoryStream(bytes)) {
Response.AddHeader("Content-Length", stream.Length.ToString());
stream.WriteTo(Response.OutputStream);
}
}
Any idea what's up?
Your code worked fine for me but you may want to try adding this as the last line of your click handler:
Response.End();

Error: while trying to OPen PDF in ASP.NET

In my ASP.NET application,When I try to open PDF file by using the below code, I am getting an error
CODE USED TO SHOW PDF FILE
FileStream MyFileStream = new FileStream(filePath, FileMode.Open);
long FileSize = MyFileStream.Length;
byte[] Buffer = new byte[(int)FileSize + 1];
MyFileStream.Read(Buffer, 0, (int)MyFileStream.Length);
MyFileStream.Close();
Response.ContentType = "application/pdf";
Response.AddHeader("content-disposition", "attachment; filename="+filePath);
Response.BinaryWrite(Buffer);
ERROR I AMN GETTING
"There was an error opening this document.The file is damaged and could not open"
Sounds like your using an aspx file to output the pdf. Have you considered using an ashx file which is an HttpHandler? It bypasses all the typical aspx overhead stuff and is more efficient for just serving up raw data.
Here is an example of the ashx using your code:
<% WebHandler Language="c#" class="ViewPDF" %>
public class ViewPDF : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
FileStream MyFileStream = new FileStream(filePath, FileMode.Open);
long FileSize = MyFileStream.Length;
byte[] Buffer = new byte[(int)FileSize + 1];
MyFileStream.Read(Buffer, 0, (int)MyFileStream.Length);
MyFileStream.Close();
Response.ContentType = "application/pdf";
Response.AddHeader("content-disposition", "attachment; filename="+filePath);
Response.BinaryWrite(Buffer);
}
public bool IsReusable
{
get { return false; }
}
}
If you still want to use the aspx page. Make sure you are doing the following:
// At the beginning before you do any response stuff do:
Response.Clear();
// When you are done all your response stuff do:
Response.End();
That should solve your problem.
You must flush the response otherwise it gets partially transmitted.
Response.Flush();
In addition to ocedcio's reply, you need to be aware that Stream.Read() does not necessarily read all of the bytes requested. You should examine the return value from Stream.Read() and continue reading if less bytes are read than requested.
See this question & answer for the details: Creating a byte array from a stream

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