i have a requirement where in i have to update the information of a record with new values.how to open the binary file and update with the new information.The existing binary file contains 5 records with serial nos.now i want to update the information of sno 1.i am using filestream, binary reader ,binarywriter SureshThere is an Island of Opportunity In the Middle of Every Difficulty
View 1 Repliesi have to update an existing binary file with new information.
binary file contains records from 1 to 5 each record contains different values one integer and five strings.
no i have to update the 1 record with the new information .how do i do that.
i am using filestream,binary reader and binary writer.
Pwd_FS = New FileStream("test.bin", FileMode.Open, FileAccess.Read)
after reading the contents of the record i will assign new values to the recorod writing back should i use
Pwd_FS = New FileStream("test.bin", FileMode.Append, FileAccess.Write) if i use append i am not able to seek to the starting point.
I am using VB2005 and trying to put an application together.What it needs to do is retrieve information from a binary file, possibly alter that information, and put it back into a new file.The file is a .wav file with data appened to the end. There is an additional section at the end of the .wav file which stores xml data.I have found that if I open this in a hex editor and make a 1:1 swap on any of the bytes that the application that the file is for can still read the XML.If I tried to add or remove characters from the XML then it would not read. I located a header byte and incremented it to resolve this.
This worked as an excellent bandage to do conversions where the data always needed to be changed to the same thing.What I have been asked to do is build logic that allows for different things to happen depending upon what data is contained within the file.The method that I am currently trying to impliment is:
Read through the file with a system.io.binaryreader
Searche for a bytestream that will signal data is coming
For example:
If System.IO.File.Exists("C: est estread.wav") Then
Dim findit() As Integer = New Integer() {&H3C, &H55, &H73, &H72, &H44, &H65, &H66, &H30, &H31, &H30}
Dim i As Integer[code].....
And then extract all the data till the end of element marker "<" It seemed like there should be a better way and I was looking for some insight. If I proceed with this method, I will have to read the file one time to gather the information and then a second time to write it all out with the header modified for length.This is my first experiene with working with binary files in this way.Also,I've been experiementing with building a string and slapping it back in at the end using the binarywriter.write(string) method.I noticed that it was putting in header characters before the string.These seem to change if I change the length of the string.At one point it was d0 07. Later it became e7 07. Does anyone know of a way to prevent this header from being inserted?
I tried a for each loop to grab all of the characters from the string, convert them to a byte array and deposit the byte array into the file, but the header remained the same. When I write the byte array generated from a system.io.binaryreader I do not get this header.
I am writing a windows desktop application in visual basic and I need it to connect to a SQL database, take a rows unique id, and using that number generate a file from the binary data that is stored in the SQL database and save it to a file directory. The part that is hanging me up is the creating the file from the binary SQL data.
View 2 RepliesI've gone through about 16 hours and two packs of cigarettes trying to figure this out. First a little background. I was using 6.0 up until 2004 when I went to prison. I'm out now, and trying to relearn the trade, using VS 2005. I'm currently porting some 6.0 code from another project, SpyCast Webcam Studio, into VB 8.0. It's disheartening, to say the least. None of the old built-in subs/functions work anymore, so I have to scour the forums to relearn each and every function.The section I'm doing now takes a snapshot from the webcam (Video API --> PictureBox --> Save as Jpeg), then upens the file to upload it to the server via HTTP POST. I've been using this code in SpyCast for years with no trouble, but I spent many hours trying to piece together the right code to open the binary file to read its contents. I pieced together two methods I found around the forums, one using FileStream() though the code I found wasn't for binary files, even though it said it was, so that code doesn't really work. Method two uses Microsoft.VisualBasic.FileOpen() and works better.
Here's the kicker. By the time I run through the rest of the rigamarole of uploading the file, by the time I read it on the webserver, it's *slightly* corrupted. It's a valid Jpeg, no errors, but the picture looks like when I use to watch the Playboy Channel when I was a kid scrambled with weird colors and whatnot. [code] Each "chunk" is basically one "line" of the file. It looks like a single LineInput() return is the text between two carriage returns. Am I correct? I tested this with a flat text file, and it looks true. However, That one input line returns the text or data with the carriage returns *stripped*! ***?!? =( Fine, I have no problem adding my own vbCrLf to each LineInput(), if I were opening text. but this's binary. A character could be Chr(10) or Chr(13), both of which are removed from the original file contents.So I could very well need to use something other than LineInput(), but I haven't found any other examples on the web using this method.
I have a VB.NET dll which pulls out binary data from and opens it as a pdf. It works fine if I create a file on the user's machine and then open that. What I want to do, however, is just open it in Adobe without creating the file on their machine first (there's customer data in the file and we don't want copies of it sitting around unecessarily).
It's possible in ASP.NET to just stream the data to a browser and open it in that without creating the file, but I can't find a similar methodology for doing that straight to Adobe. Does anyone know if this is even possible or do I have to create the file in order to have it open?
can someone teach me how to open the file with binary mode in VB.NET?
View 6 RepliesI need to make an E-Search engine for collage library , i can make it by using streamReader and streamWriter , but unfortunately i have to use Binary to make this project ... i've to many fields to put it on DAT file , and i've to use SPLIT to split lines and make arrays ..
what is the best way to do that ? how can i write an opened binary file on textbox and convert text to array ?
I am trying to open a .csv file via openfiledialog and then display information on a datagridview...What would be some ways to approach this? I have tried reading the file, separating the values by commas and placing them in a string followed by placing the string into a list. I place them in a list because I have more than one string of text I want operated in the CSV file. How can I display each string of separated values onto my datagridview?
View 4 RepliesI'm starting to learn programming in Visual Basic .Net , I need to open an excell file show the information on the screen,
View 2 RepliesIm using visual basic 2010 and im building a program that will basically, you click on something in the list it will automatically open a .dat file pull the information that it needs, and then proceed to enter it into a box on the right. Well heres my issue i know how to do everything else but i cant seem to imitate this image, i need to know how i can make a list like this where the whole row is selectable, and the items/subitems are divided.
View 9 RepliesI have code which saves DGV contents including check box columns as a comma separated text file. I also have correct code which will take the text file and re-insert it into the DGV at a later time. This all works.When I'm working on the DGV, I have this
Private Sub DataGridView1_CellValueChanged(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellValueChanged
If DataGridView1.Columns(e.ColumnIndex).Name = "Column12" Then[code]....
So that when the check box is true, columns 1 and 3 turn different colours, and when false, go to a yellow colour.However, when I "re-insert" my DGV info from my text file, the check boxes come back correctly - as true and false on the right rows - but columns 1 and 3 don't change colour. I've tried a "DataGridView1.Refresh" option but not getting it to work.The DGV is unbound. I need it to recognise which check boxes are true and update automatically when the information is opened from a text file.
Supposedly I create a file called "hi.txt" and I use Process.Start(filename) to open it. then I File.Opentext(filename), edit it and close it using stream writer/reader, while I still have that file open.
In order to see the changed text I need to close "hi.txt" and reopen it.
Is there a way to automatically do that? Been experimenting a bit but with no luck.
Tell & interduce a pdf the full explain about file programming in vb.net(such as create , open in binary and .... , explain file stracutre and all)? a full article (most of the ways about file in vb.net)?
View 4 RepliesWhether I am using VB 2008 Express or VS 2010 Beta 1 Visual Basic, I get the same error: "Debugging information for 'EXCEL.EXE" cannot be found or does not match. Cannot find or open the PDB file" I have filled in the Debug Tab information: Start external program: C:Program FilesMicrosoft OfficeOffice12Excel.exe
[Code]....
I have a csv file. I need to open it, delete whole row on basis of a column value, Update few of the column values and save the file as .dat file. I am using VB.net 2010
View 1 RepliesI know how to insert a new row into a table that has a binary column. But is there any way to update the binary column once that row has been added? So far an exhaustive google search has turned up nothing. Get the current row that I wish to update delete the row that I wish to update Create a new row with the information from the row I wish to update plus the new binary It just doesnt seem very elegant, and I was hoping I could do the same thing with an update statement. Here is the updated code I am using now for reference
[Code]...
any1 has any ideas on how to code a patch maker, (binary differential update) so when i run my patch maker, it output a program (*.exe) that will update files on another machine or local machine, assuming that old files to be updated to a new file having the same data in result;
and also the output patcher should be smaller in size (compressed)currently wad i could think of is a very very simple one but totally useless and not efficient and result large file size patch
1. where mine is read both file data
2. is both byte the same ?
3. [if not same ----> write down the marker value in outputfile1 and byte value in outputfile2]
3. [if same ----> do nothing]
4. read byte if available
5. (marker + 1)
the marker value is how many byte have been advanced so with resulting patcher will read those marker values to advance to the file address (which is the position number) and update accordingly to its byte value outputfile1 is marker values, outputfile2 is byte values corresponding to outputfile1 marker value to advance to the byte position
I am trying to use the following stmt in VB and I am getting an error: Open (objFiles(lngLoop)) For Binary Lock Read Write As #hndZip_File On the "Open" word I am getting "Open is not declared. File I/O functionality is available in the Microsoft Visual Basic namespace." On the "For Binary Lock Read Write As #hndZip_File" I am getting "End of statement expected" I originally thought I had to add "Imports Microsoft.VisualBasic.FileIO" but this did not do anything.
View 2 Repliesi need to read binary file and in this file found the string and replace it with other one and save the file afterwords. I found many example to read binary, but to find and replace is for me mistery.
View 3 RepliesI am creating a update member page. I would like the page to auto retrieve the information he or she originally used while registering on my site and display them into the individual textboxes of the update profile page, this is to prevent the hassle to rekey in every individual details and allow the user to edit what he or she wants before it is updated into the database. The problem that I encountered was not able to update the changes in the database. When key in the latest data in address text box and hit submit button, the old data in address text box remains and did not update the database
Imports System.Data
Imports System.Data.SqlClient
Imports System.Web.Configuration
[CODE]....................
I need to write data to a file, preferably in binary format, but I am unaccustomed with the concept. Where's the easiest place to get the basics? I could come here with a specific need, but I'm at the point right now where I am more willing to work within the confines of keeping it simple.
Here's what I know:
1. how to open a new file
2. how to specify the record length
3. how to close the file
Some specific questions:
Does the record length have to be constant throughout the file?
Can I read the nth record without reading the whole file?
I have a dataset with a number of data columns, due to sizing issues I've updated a number of the varchar columns from say VARCHAR(20) to VARCHAR(50).I'd like the DataTable to automatically grab the new column information, is this possible? I'd rather not go through each column in the table and update the length.
View 1 RepliesI want to know how you can open a form with specific information as if you are just calling a sub, kinda like how a message box is. Example:
MyForm.Show("The form title")I also want to know how I could apply this to forms that are being created from pre existing forms. Exaple:
vb Dim NewMyForm as New MyForm("Title Text")'Now I want to know for each of these next 2 lines of code, think of them as being different codes all together.NewMyForm.Show() ' orNewMyForm.MdiParent = Form1NewMyForm.Show
My listview clears and updates every 2seconds. Is there an easy to refresh the list information without clearing first? Like taskmanager
View 2 RepliesI have built a very simple application which has buttons, and dropdowns containing links to intranet/internet sites.As I have no Idea on how to put them into a database for easy maintenance, this app will no doubt cause me pain.Nevertheless.. When I do create a new revised version of the file.. eg 1.0.0.1 how to I go about setting the application to auto check for updates ?
View 2 RepliesI have a collection of objects (classes I created), and each one ties to a record in a database. I want an easy way to update the information, so I thought about declaring a record in the class, that would tie to the record on the database. However, I'm having a problem updating it now.
1) Can I declare a global variable for the data context, and leave it open the entire time the program is running? This would solve my problem, but I don't know if I can do that.
2) If not, besides coming up with a complicated class to do this, is there an easier way? Here is an example of what I am trying to do:
VB.NET
Public C as Record
Public Sub GetValue()
Dim SQL As New DBDataContext
Dim X = From T in SQL.Records Select T
[Code] .....
how I could check if a certain file is in text or binary format?I'm using VB.Net 2008 Express.
View 2 RepliesProgram to convert binary pdf file to tiff file in VB.NET..?? We can use third party tools also..???
View 1 Replieshowever, I am stuck at BinaryReader.actually this is what i am trying to acheive through VB.NET.say for the following file type :
JPG file = FF D8 FF E0
BMP file = 42 4D BE 4E
PNG file = 89 50 4E 47
GIF file = 47 49 46 38
the above are the 4-byte headers in Hex(raw) I need to read these headers of any given file using OpenFileDialog using Button1_click event,on selection of any given file(*.* filters ON)it should use the BinaryReader and look for only 4-bytes starting from offset 0, and it should not go to EOF marker (-1).and have a variable to hold this 4-byte header value, to run this in a database table which will check the same header value in the table and would display the corresponding extension of the file. from the table.
I can do this using case, if then...etc.however, I have to do it using Database and also i need to check for testing purpose to use MsgBox() to display this variable which is holding the 4-byte header.however, the MsgBox doesnt allow anything other than String.
PS: I tried studying the methods like:
FileOpen/Seek/Peek/ReadBytes().
but still not sure how to get them work.