I am a total noob to VB and am only doing an A-level in computing. i'm using VB 2008 express edition am trying to make a windows form application which picks a random file from a folder and displays its contents in text boxes when a button is clicked.
View 3 RepliesI am writing a program to calculate Pi to several hundred billion decimal places and this will require lots of GB of memory. I wrote a test program in VB2008 that saved the first 16 digits of Pi (without the decimal point) to both a text file and a random access file, just to be sure it was outputting the numbers properly. For reference the first 16 digits of Pi are:
View 8 RepliesI have managed to learn a little of VB 2008 but I'm still struggling. I managed to convert one VB6 program to VB .net but all the file IO in it is sequential access.I'm trying to convert a VB6 program to .net. This program uses almost entirely random file IO.In one of the books I have, I found an example which, with a minor mod worked. I tried using that code to modify my program and it does not work. In my code, the FileGet results in the obj containing null strings. Yet in the sample program using the same structure, the obj contains actual data.The file is being opened because the record count is calculated correctly [iUpper = LOF(F_Trk) / TrkLen].
I used a Type in VB6 which I converted to a Structure in VB 2008. The function in which the problem occurs is below as well as the Structure declaration and the Function it calls (PAB) which is a derivation of the PathAddBackslash API call.Is there an easier, more efficient way to achieve the same results in VB .NET?[code].....[code]......
how to read and write random access records in .NET. Now I know random access files are dead and the response on every query I found with google/bing/yahoo searches was don't use random access use Binary serialization but I can not. I have a situation where I need to read and modify 256 byte records in a file that is used by another application.
Now for a bit of background the file is made up of 27 fixed length records of 256 bytes. Each of the records has a separate structure consisting of 30-120 fields. The proplem I am having is I can create the record structures but when using the FileGet method I am receiving an error. Now I have found samples that showed the same format I am using that claim to work.
The error I am getting is Option Strict On disallows narrowing from type 'System.ValueType' to type 'ProgramName.ModuleName.Record' in copying the value of 'ByRef' paramater 'Value' back to the matching argument.
The basic layout (simplified) is as follows:
Code:
Structure Record
<VBFixedString(6)> Public SomeParam as String
Public SomeNumber as Short
[Code]....
Now the overloads for FileGet show all of the data types including Object. But I have tried various methods to retreive the 256 byte record but without success. Do I have to actually read each of the several hundred fields of the structure one by one? Or am i overlooking something (I have been known for this in the past)
Or (and I'll kick myself if this is the only way) do I just have to set option strict Off in the module and the code as above will actually work.
I would love to be able to just ditch the random access file but I have to keep it for compatibility with several other applications at this time.
I'm building a basic text based adventure game (main purpose is to just keep me fresh between programming classes during break, since I have my final VB course next semester and am trying to explore some different concepts and ideas for coding in VB) in Visual Studio 2008. During the character creation process, the user is allowed to choose a portrait to represent their character in game. I've loaded up my resource file with the portraits in question, but there is one thing I'm having some trouble with when it comes to selecting the portraits from that file. Keep in mind, I know how to do this exact thing by loading the pictures up into their own asset folder and grabbing them from there to display on the form. The resource file seems like a more intelligent way of doing it, but I've not used it much in past applications.
So, when the user clicks on the "next" arrow to cycle through the possible portrait choices, I want to change the current image in the picture box from, let's say, image1, to image2. Straight forward and all.I could load all of these images up into an image list, but again, this is all for exploratory purposes, so the following if statement is being used for that purpose only. I plan to code a more effective way of cycling through the images at a later date.
If picCharPort.Image = My.Resources.Image1 Then
picCharPort.Image = My.Resources.Image2
End If
For some reason, I am fully capable of assigning My.Resources.Image1 to picCharPort.Image normally, but when I attempt to switch the image to another image like in this if statement, it creates and error.It essentially does not like the "=" operator being used, so I switched it to Is, and it still doesn't work (however, without displaying an error).(considering, the portrait options change depending on character class/gender, etc)?
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 am working on a VB Console Application that takes an Autocad drawing type DWG and converts it to a PDF using a shell command that calls a third party application. In this case, acmecadconverter.exe from www.dwgtool.com. Then the PDF that is created needs a unique watermark, so I call a second application for that called pdftk.exe from www.accesspdf.com/pdftk/.
Everything works as intended, except when I try file names that contain spaces. The file system object does not tolerate spaces in the drawing file name. For instance, the following command gives me a system.io.filenotfoundexception...
My.Computer.FileSystem.RenameFile("Test Flowchart1.dwg", "Test~Flowchart1.dwg")
It's the same problem for all of my File System commands. Either file not found or invalid arguments.
The complete script I'm using is here:
Code:
Sub Main()
Dim arrArgs() As String = Command.Split(","), _
i As Integer, folderPath As String, myPart As String, _
[Code].....
I'm currently developing an editor for an AFL management sim.I want to be able to load three or four multidimensional arrays to the program, then save them to the same file. I tried the tutorial on here but got completely muddled up. Why can't it be easy like in VB6 When it was like 10 lines of code tops!
View 5 RepliesI have a program that can save to a .txt file.The issue is I need it to be done in a tab delimited way.Basically:
TextHere<Tab>TextHere<Tab>TextHere<NextLine>
TextHere<Tab>TextHere<Tab>TextHere<NextLine>
I have this so far, but all it does is put the TextBox1.Text next to TextBox2.Text
Code:
SaveFileDialog1.Filter = "Text files (*.txt)|*.txt|All files (*.*)|*.*"
Dim FileWriter As StreamWriter
Dim results As DialogResult
[code]....
Our program will start with the help of a FileSystemWatcher object. How can we check or the file is total copied, for example the file is 100 Mbyte it take a time it's ready for use. Idea:
Do While True
Try
N = testForUse(BigFile)
If N = 1 Then Exit Do
[CODE]...
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.
Error is coming Registry Access is not allowed.While Opening a Key.
Code:
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
NewDelete("HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun", "Sonia")
End Sub
[CODE]...
I've had a bit of a look around the net and on the forums but I've yet to find an answer to my question. I've got Visual Basic 2008 Express and I'm trying to write some registry entries, I can write strings fine just using
[Code]...
I'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.
trying to find a decent answer for my question; I do have a utf8 file which I (down)load, manipulate and wanting to save back again.The result always is that the file I produce is not in utf8 format;
Dim fs2 As New FileStream("c: est.dat", FileMode.Create, FileAccess.Write, FileShare.None)
Dim w As New BinaryWriter(fs2, Encoding.UTF8)
[code].....
trying to input a text file that's tab delimited that looks something like this.
2.2 5.6
3.7 9
1.2 9.1
[code].....
i am working on an application called logonscreenchangerxp i made my program and when i run it on xp virtualmachine i get errors the program is made using vb 2008 and using .net framework 2.0 i am not able to get full permissions to modify boot.ini file and a regisrty value and to delete a file
View 5 RepliesCurrently, I am try to get the email addresses that have been saved or stored by the user of the computer. This isn't the emails that the user has sent or received, or the contacts he/she has in his address book. Just simply the email accounts that have been accessed from the computer.I know that there are some locations stored in the registry that have the email account. The email addresses that are used on the current computer. I just can't seem to find them on my computer.I am not sure if the registry is the only place to find it or if it stored on the web browser such as internet explorer or google chrome.
View 1 RepliesI am writing an application that connects to a specific com port. This com port can change depending on how many physical ports are on the PC, and if other USB devices have installed com ports before this one.
I have the communication to the com port all working great, but I need to get the com port description not just the "COM#" which is all I currently get.
I found in the registry where the description is stored but am having trouble doing what I need.
In this key:
Code:
HKEY_LOCAL_MACHINESYSTEMControlSet001ControlClass{4D36E978-E325-11CE-BFC1-08002BE10318}
there is a varied number of sub keys. The are numbered 0000-NNNN depending on how many ports you have. Inside each of these keys, there are multiple values, although I am only interested in one or 2 of them.
My problem is, that I do not know how to get a list of the subkeys (the 0000-NNNN keys/folders) from the original key I posted. I have looked through a few registry tutorials, and I can view the default value in the listed key, but I could not find how to list the subkeys of the listed key.
Does anyone have any sample code they could share that shows how I can get a listing of subkeys, and then run through those subkeys checking for a specific value in one of the strings contained in the subkey?
I am using VB.net 2008 and Windows XP.
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!
I've got an app which uses a background worker to copy files. It works fine but some files are quite large and it "appears" as though the app isn't doing anything. Is there an alternative to the File.Copy method of copying files so I can report on the progress of individual file copies, like the percentage complete?
View 19 RepliesI need to implement a routine to read a plain text file, BUT that file has a predefined format.The file format is as follows:
Quote:
<FILE_PROPERTIES> 'The "< >" also appears
Propertie1="String" 'It's possible to have spaces after or before the "="
Propertie2="String"
Propertie3="String"
PropertieN="String"
[code]....
Is there any Windows API Routine to read something like that?Or could you point me an URL where something is implemented?I don't want a procedure to read the file line by line and comparing them with Line Input because blank spaces, empty lines and comments starting with " // " may appear too, and I don't want to take them into account, but also I need to save changes to the file, but only to the modified section, without having to read the whole file, and re-write it completely.
Binary access can't work, because I don't know what's the size of each "section", since the number of elements into it can change.
I need something like the "ReadINI" Windows API Procedure, but allowing me to read the "[XXX]" sections headers, and also the "<XXX>" file title header.
Before I begin I would like to mention that I am not a noob in VB, it's just I've never had to do anything this complex before. Basically what I want is to have a program that you can load a txt file in, have it copy key words, and paste it in a textbox so I can use it later on. So in this text file, there is a bunch of info, but I am only needing a certain part. Here is an example of a text file (actually a .dat file, but is easily read):
[Code]...
My application runs on a "server" machine and provides files (10megs - 100megs each) to 8 other computers. Currently this is done using a standard shared folder on all 8 computers and the server simply copies the file to \ComputerNameSharedFolder - and everything is great.However, due to new policies we need to remove all shared folders, so using a simple \ComputerNameSharedFolder is no longer feasible. Therefore I need to find a way for my application to be able to share these files in a safe, secure, and compliant way.There has been talk of using sFTP which would require each system to have an sFTP server running at all times (controlled by the application somehow), or also SSL was talked about as it can be integrated into the application easily, etc...
View 1 Replieshow to save information into a text file from runtime VB2005. However, I wish to be able to write the information into any kind of form of file that cannot be simply opened and read by anyone (such as text file can be). Is there anyway that VB2005 can do this?
View 2 RepliesWhat i am trying to do now is to show the content of the dnsredir.ini file on the forms and able to edit it.
The dnsredir.ini file file looks like this
;Configuration INI file for DNS Redirector v6.4.7
Logging=Normal
ListenOnIP=172.23.128.33
[Code]......
I'm using the SaveFileDialog to save listbox info into a text file. The files save fine, but when you go to save the file, if you hit the cancel button, it will overwrite the previous file you saved, because it's name was the same and it seems to save the previous file as the new name for your next file. Is there any way to catch if the user clicks cancel, and then exiting the sub if they did?
View 2 RepliesI need to be able to change a path inside a document ( a config file to a program) to the current directory of the application im creating in VB so the text file looks something like
Quote:
something=234
blabla=io
ServerRoot=C:Server
i need to change c:server
I am trying to code a delete button for a browsing program based on data from a txt file. I have coded the buttons to sort(ascending and descending), append to the text file, search the text file, but I can not seem to get the delete function working. I am using VB 2010, this is what I have so far:
Code:
Dim deleline As String
Dim line As String
Dim isFound As Boolean = False
sr4 = IO.File.OpenText("Students.txt")
[code]....
Years ago when coding with VB6 and earlier, I used a file open command to create, read, and write a file that made it easy to store useful information.I believe it was binary and you wrote/read the data to a specific line in the file. When you opened the file with something like notepad, it just showed random ascii chars. When I needed a line of data, I could specify what line to load it from.
View 2 Replies