Loading A File Into Memory Stream Buffer And Creating New File With Same Content And With Different Filename?
May 31, 2011
I don't know whether it is simple or not because i am new to programming. my requirement is : In my vb.net winform application, the filenames of the files present in "D:Project" willbe displayed in DataGridView1 control. Now I want to load these files one after another into memory stream buffer and add the headers("ID","Name","Class") to the content in the file. Then I want to save these files in "C:" with "_de" as suufix to the filename i.e.,sample_de.csv.
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Jun 1, 2011
I am working on vb.net win form. My task is display the file names from a folder onto gridview control. when user clicks process button in my UI, all the file names present in gridview, the corresponding file has to be loaded onto memory stream buffer one after another and append the titles to the content of the file and save it in hard drive with _ed as a suffix to the file name.I am very basic programmer. I have done the following attempt and succeeded in displaying filenames onto gridview. But no idea of later part.
'Displaying files from a folder onto a gridview
Dim inqueuePath As String = "C:UsersDesktopINQUEUE"
Dim fileInfo() As String
[code]......
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Mar 3, 2009
i need to read a large file stream binary my code is Dim sr As New IO.FileStream(srcFile,
[Code]..
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Dec 5, 2006
I'm using the ShockwaveFlash ActiveX control in a VB.NET Windows Forms application and i'm wondering.Is it possible to load an SWF file into the ShockwaveFlash ActiveX object from a memory stream rather then from a file name?
I've noticed that the ActiveX object has such properties as "InlineData" and "MovieData", possibly these could be used.
I've also noticed someone has used Windows Messaging to send a pointer to a stream to the ActiveX control, has anyone seen this done?
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Jun 2, 2011
I have a filename(including it's path) in a string. Now i want to load this .csv file into memory stream. ex: Dim filename as string="C:UsersDesktopabc.csv"
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Sep 26, 2011
How to convert memorystream byte array to csv file. I have GetExport method that converts rpt file to excelformatted memorystream and then returns that as a byte array. Is there a way to convert this byte array to a csv file? Due to some reasons I can only pass this byte array back to calling function.
Public Function GetExport(ByVal reportID As ReportID) As Byte()
Dim byteArray As Byte() = Nothing
Using expRptDoc As ReportDocument = New ReportDocument()
Dim rptFileName As String = Server.MapPath(ReportCommand.GetXMLReportPath(reportID))
expRptDoc.Load(rptFileName)
[Code] .....
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Feb 6, 2012
How do you pass a wav file to a mediaplayer via a memory stream? In other words is it possible to pass a stream instead of a url to play a wav file?
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Feb 24, 2012
I have a user interface app that allows you to drag/drop in files - and it turns them into HttpListener request POST's to another EXECUTABLE that I have running - let's call it BACKEND1. BACKEND1 will be running on a SERVER when this gets ready for production use. Lots and lots of users running the UI - all dragging in files - all getting POST'ed to BACKEND1 - with the file included as a memory stream in the POST. BACKEND1 responds to the UI with a "sequential" file number assigned to the file centrally on the server.
On the SERVER is also running another EXECUTABLE - let's call it BACKEND2. It's job is to work with the DRAG'd in files. Both BACKEND1 and BACKEND2 sit on the same SERVER. At the moment I am writing the memory stream to DISK in BACKEND1 - and POSTing the FILENAME to BACKEND2 for it to work on. Would it be better to not write the file in BACKEND1 but instead include it in the POST to BACKEND2 - where it can be written to DISK? Is having LARGE HTTP REQUEST's a burden when sent between two EXECUTABLES on the same machine?
My primary goal is to have a really available BACKEND1 talking the the UI instances running out in the world. I'm concerned that doing the file i/o in BACKEND1 is "expensive" - and I don't care about the performance of BACKEND2 as much. just looking for opinions. I guess ultimately I'll have to bench mark this myself in a production environment to get a real answer.
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Oct 4, 2005
WebBrowser Example.zip IntroductionBecause the WebBrowser control that we use in .NET is a COM control, not all of its uses are straightforward and some of them (even those which seem like they should be easy) require that we dip into our Interop toolbox in order to properly implement them.
A perfect example of this is loading HTML content into the WebBrowser from memory, rather than a file or a URL. Anyone who's ever used the WebBrowser control before is familiar with the Navigate2 method, which tells the control to load content from a URL (or path to a file). Loading HTML content from memory, however, is a rather elusive practice because of the many steps involved in making it work.
MSHTML.HTMLDocumentYou might notice that the WebBrowser control exposes a "document" property. The object returned by this property can be coerced to the type of "mshtml.HTMLDocument" (you must add a reference to MSHTML to your project in order to make this work) as follows:
Code:Dim clsDocument As mshtml.HTMLDocument = CType(WebBrowser.Document, mshtml.HTMLDocument)
(NOTE: You will have to add a reference to the COM library MSHTML to your project to make this compile)
Once we create an instance of HTMLDocument, a whole new world opens up to us, providing all sorts of DOM access to the content of any given Web page.
If we were to create our own HTMLDocument object from memory, we could use the "write" method to write HTML content to the document from a string variable, like this:
Code:'initialize the document object within the HTMLDocument class... clsDocument.close() clsDocument.open("about:blank")
'write the HTML to the document using the MSHTML "write" method... Dim clsHTML() As Object = {sHTML} m_clsDocument.write(clsHTML) clsHTML= Nothing
WebBrowser Control ImplementationUsing the HTMLDocument returned by the "document" property of the WebBrowser control, however, is not as straight-forward. Because of the way that this object is created and initialized in memory (by the COM WebBrowser control), the "write" method fails when called as above. In order to write content to the HTMLDocument exposed by the WebBrowser control, we must first marshal the string value to a memory space that is compatible with COM. Once the string is properly marshalled, the COM interface IPersistStreamInit (implemented by the HTMLDocument class) must be used to pass the value into the object.
Interop DeclarationsIn order to pull all of this off, we must declare several Interop pieces, including an enumeration, a function, and two interfaces. The declarations for these pieces are as follows:
[Code]....
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Nov 25, 2011
I have a function that accepts a string and generates an email attachment based on that string. It works fine for html pages, text documents, and so forth but I can not get it to generate a PDF file.
Code:
Public Sub SendMail _
( _
ByVal strFrom As String _
[code]......
If I save the file attachment as Whatever.PDF i get the error that it was not encoded properly.I am using datadynamics active reports PDF exporter to generate the PDF
dim pdf as new datadynamics.activereports.export.pdf.pdfexport
sendmail("from@", "to@", "test", "test", pdf.tostring, "pdf.pdf")
I think the problem is I am converting the PDF to a string, and then trying to convert it back to a PDF and attach it to the email but I am not 100% sure.
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Jun 5, 2012
I am using iTextSharp with VB.Net to stamp images onto PDF documents. (Since this is not language specific I tagged for C#, too.)I have two applications using the process.The first uses the bytes from the memorystream to display the PDF documents online. This piece is working. The second uses the same function but instead saves the PDF to a file. This piece generates an invalid PDF.
I have seen some similar questions, but they are all creating a document initially and have a document object in the code. Their memory streams are corrupt from the outset. My code does not have a document object and my original memory stream opens fine.
Here is the place where I get the error: (I have to put the buffer from m into a new memory stream because the stamper in the fillPDF function defaults to closing the stream unless marked otherwise.)
Dim m As MemoryStream = PDFHelper.fillPDF(filename, Nothing, markers, "")
Dim m2 As New MemoryStream(m.GetBuffer, 0, m.GetBuffer.Length)
Dim f As FileStream = New FileStream("C: emp.pdf", FileMode.Create)
[code]...
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Sep 28, 2010
I have a user interface app that allows you to drag/drop in files - and it turns them into HttpListener request POST's to another EXECUTABLE that I have running - let's call it BACKEND1.BACKEND1 will be running on a SERVER when this gets ready for production use.Lots and lots of users running the UI - all dragging in files - all getting POST'ed to BACKEND1 - with the file included as a memory stream in the POST. BACKEND1 responds to the UI with a "sequential" file number assigned to the file centrally on the server.
On the SERVER is also running another EXECUTABLE - let's call it BACKEND2. It's job is to work with the DRAG'd in files.Both BACKEND1 and BACKEND2 sit on the same SERVER. At the moment I am writing the memory stream to DISK in BACKEND1 - and POSTing the FILENAME to BACKEND2 for it to work on.Would it be better to not write the file in BACKEND1 but instead include it in the POST to BACKEND2 - where it can be written to DISK?
Is having LARGE HTTP REQUEST's a burden when sent between two EXECUTABLES on the same machine?My primary goal is to have a really available BACKEND1 talking the the UI instances running out in the world. I'm concerned that doing the file i/o in BACKEND1 is "expensive" - and I don't care about the performance of BACKEND2 as much.
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Jun 12, 2009
I need to load the contents of a text file (itemInfo.txt) into a list box
Public Class MainForm
Private path As String = "L:Visual BasicSequentialHW"
Private Sub MainForm_Load(ByVal sender As Object, ByVal e As System.EventArgs)
[Code].....
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Feb 13, 2011
When we use system.io.ReadLines the content of the file should not be loaded to memory right? say I want to create a function. The function accept a string, say "post.txt" where post.txt is a large file (3G) I want to put the first 100k line of post.txt on post.txt and the rest on reserve_post.txt
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Mar 1, 2012
how load a string containing the source for a .exe strait into a process without accessing the hard drive.
Currently my code goes something like this...
Imports System.IO
Dim file As String
file = file_source
[Code]...
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Feb 6, 2011
Is it possible to load the content of a text file (.txt) into a listbox or combobox if the text file is located in a webpage?let's suppose that the file is located at url...how would i load the content of the text file into my listbox/combobox?
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Oct 8, 2009
i'm creating some PDF reports for my application, i wish to open them directly without saving them, so to allow the user to decide what to do with them.
I've build my procedure, i thinks it works fine (the same procedure with filestream instead of memorystram show me what i want).
But i don't know how to open the document written using memorystream...
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Jun 26, 2009
how do you transform an address like "file:///d:filename.ext" in "d:filename.ext"
without dirty string manipulation??
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Aug 24, 2010
I have a standard WMA stream, streaming in constantly via the internet. I need to write an application to stream this audio, and looks for any periods of 'silence'. When it detects silence, it runs an event.
For the purposes of this, silence is defined as three seconds of zero-level audio. The stream keeps going in a technical sense, but there is no audible noise coming through it.
However, I want the program to detect the silence while it is still in the 'buffer'. That is, the user won't hear this silence before the program detects it is there.
The audio shouldn't stop as it is analysing this silence - it needs to keep playing the audio constantly to the user.
I'm open to using whatever suitable API is out there - such as BASS, or the Windows Media extensions built into the dot net platform.
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Jul 1, 2011
I'm using the FileSaveAs dialog control to allow the user to select a filename to save a file either as a doc file, an rtf file or a pdf file (that part was easy).However, after a bit of testing, it seems that the file extension doesn't automatically change when selecting the different file types.If the filename in the dialog is Foo.doc and I select FileType *.pdf and click "Save", my app still tries to save the file as a doc type.Virtually every other MS app automatically changes the extension to match a selected file type from the Office Suite to Paint. here's my code:
Dim dlg As New SaveFileDialog
dlg.InitialDirectory = m_sReportFolder
dlg.FileName = sProjectName & ".docx"[code]......
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Apr 7, 2007
I encountered the error:The process cannot access the file <full file path> because it is being used by another process.during System.IO.File.Delete(filename)I have opened the file using:pctPhoto.Image = Image.FromFile(filename)before I delete the file.
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Nov 22, 2011
I have a problem with the cryptostream, if i write the stream to a memorystream the memory that the stream used is still alocated and i have no way of unalocating it.what am i missingdoing wrong? im using-using on the streams,readers and crypto stuffs so the framework should shut them all down right? i tryed calling .close and .dispose but nothing ,in fact i moved it all over I have provided the sub that im using for the encrytion im in .net 4.5 so there is a lil async stuff but i know thats not the problem coz i moved this code out of my main app(.net 4) for testing to see if i could fix the problem.[code...]
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Nov 5, 2009
In VB 2005, I am calling a C++ DLL function that returns the address in memory and size in bytes of a jpeg image. How can I load that jpeg image directly from memory into a picture box in my VB form? I cannot afford to save it to disk first.
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Feb 9, 2009
I am writing a backup program that zips files. Using some sample code I have the following that creates a zip file. Problem is it does not get any subdirectories or files. Where am i going wrong?
Dim azFileNames() As String = Directory.GetFiles(SourceFolder)
Dim objCrc32 As New Crc32()
Dim zipStream As ZipOutputStream
[CODE]...
Alternativley, there is another component to the zipping dll that I could probably bypass the above altogether. It is: FZ.CreateZip(DestFile, SourceFolder, True, "", "") Where DestFile is (Output stream as system.io.stream). I'm trying to read all the files, directories, sub dir and files, etc from a specific location, let's say 'My Documents' into Destfile in which the FZ.CreateZip zips the file. FZ is FastZip which is from icsharpcode.net. They have c# examples, but that's greek to me. I'm trying to just learn VB!
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Jun 9, 2010
If i use a stream to modify few bytes in a file without changing the total number of bytes
does the stream rewrite all the file even if just few bytes have been replaced?
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Mar 10, 2010
Is there anyway to take a static stream reader, and switch it to another text file based on the user changing the file?
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Jun 21, 2010
i would like to ask is there anyway to read a txt file with UTF-8 encoding using streamreader or filestream. the txt file is contain some extended ASCII that makes me cannot read the characters properly. I hav tried Encoding.ASCII.GetString(Encoding.UTF8.GetBytes()) but still it return wrong character when it's reading extended ASCII code.
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Sep 19, 2010
I want to be able to able to read the dimensions of a TIF image without loading the entire file.
PS Using Visual Basic 2008 on Vista64.
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May 29, 2011
i am making a game in which the file stream gets a certain file(lets say a.txt) and it reads it, if it has certain values stored in the file it returns boolean(this is a function), then a sub procedure writes to the file using a streamwriter and a filestream using the same file. I am having problems, sometimes visual basic says that another process is using the file, this is before i closed the filestreams and the streamwriter or streamreader, then it gives me errors when i close the files, it tells me that it can't access a file that is already closed, i thought the filestream gets the file and lets the streamreader or streamwriter read or write to the filefound out the problem?
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May 30, 2009
is it possible to report the percentage of file written by a file stream wile it is writing a large file?I am using a code like this one to write a large file
Using Fs As System.IO.FileStream = System.IO.File.Create(FolderPath)
Dim bf As New BinaryFormatter()
bf.Serialize(Fs, data)
End Using
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