As the title says can I create a memorystream then use it in a FIFO manner like a Queue.When you use memorystream.write it writes data at the memorystream.postion.If I then want to read the beginning of the memory stream I have to set position to the beginning and do a memorystream.read.
View 4 RepliesOk say I have this Dim MyQueueOfClients as new Queue (Of TcpClient) I also have two threads.
In thread one a TcpListener waits for connections then adds a connected TcpClient to MyQueueOfClients.
MyQueueOfClients.Enqueue (TcpClient)In thread two I then check to see if there are any Clients in MyQueueOfClients. If so I then remove them from the MyQueueOfClients.
MyTcpClient = MyQueueOfClients.Dequeue I think the question Im asking is this thread safe?
Can I Enqueue and Dequeue at the same time from different threads?
Well it helps if you read everything. I have just read this as well
A Queue(Of T) can support multiple readers concurrently, as long as the collection is not modified. Even so, enumerating through a collection is intrinsically not a thread-safe procedure. To guarantee thread safety during enumeration, you can lock the collection during the entire enumeration. To allow the collection to be accessed by multiple threads for reading and writing, you must implement your own synchronization.
I'm breaking my head over the next problem. I have 2 applications (client/terminal). the client reads out the webcam and generates an image. This image needs to be send to the terminal which can accept multiple clients. At the terminal all received images are placed in an ordered panel. The purpose of this application is to monitor multiple webcams.What i can't get to work is how to send it on the client side and receive on the terminal side.
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I'm using WinPcap to capture incoming data. Basically I'm dealing with a continuous stream of incoming data, either as byte array or as memorystream (pieces up to 64kb).
I need to check this data to see if there's a certain url and then extract it.
The url I need to find looks like this:http://201.122.38.5/data/today/798572987-589571?139805890582 The length of the 'code' after "/today/" is always the same. The IP address changes. What's the best/fastest/most efficient way to continuously check these byte arrays or memorystreams and extract the urls without hogging the CPU too much?
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I'm trying to make a program that will allow people to queue certain tasks at certain intervals. (i.e. the task is done every 15 minutes, etc.) They can make as many tasks as they want, at whatever intervals they want. How can I possibly make a task queue? Like, how can I queue up code that I already have made to be run every so and so often, according to what the user inputs? And, if 2 tasks are started at the same time, they will both still be done, it's just that one will be done as soon as the first one is complete.
View 4 RepliesI am using a message queue successfully as I am testing while I am writing a new program. (This is my first time using a message queue.) I have to have multiple instances of my program running, so I was wondering if this would be a problem with the queue? I have tested it and it looks fine, but I didn't know if it is by coincidence, or if the queues were separate.
View 6 RepliesThis is the first time I have used this messaging library and used some example code to implement it. The first time I ran it it worked perfectly but I abruptly stopped the code since my parsing method seemed wrong. So when I restarted it, the code freezes at the following line:
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I have a form that has a queue and i want to transfer that queue to another queue in another form. however when i try to use the elements in the second queue after transfer, I get the error message queue empty!below is my code
First Form
Imports System.Collections.Generic
Public Class Form1
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I have a problem with a memory stream.
I extract from an archive a Jpeg that's about 256 Kb, load it into a memorystream and display it into a picturebox
when doing that, my app ram ussage grows with 50+ MB
Here's the code
zip.Encryption = EncryptionAlgorithm.WinZipAes128
zip.Password = MainFrm._Pass
Dim str As New MemoryStream
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I thought that when a variable went out of scope (like a variable declared within a method - when you exit that method the variable is out of scope) then it was eligible for garbage collection and when it was garage collected the Dispose method is called on it. Now I know that it does not get disposed immediately but I assumed it would be basically as soon as the process starts to take up quite a bit of memory.However, I found that my app's memory usage seems to constantly increase when I dont manually Dispose of a specific method local variable. Of course its good practice to call Dispose and ordinarily I would but I just didn't realise that this particular class actually implemented IDisposable. The class in question was the System.DirectoryServices.SearchResultCollection class, and I was looping through the items in it like so:
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I am having an issue using BinaryFormatter.Serialize. I have this generic extension method to "clone" an object via binary serialization:
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This is killing performance. Anything more that about 7 or 8 clones brings the app to a halt. Why would this happen? The USING block ought to ensure the MemoryString is disposed of, right? Shouldn't a new MemoryString be created each time? I would think since the same original Mode object is the source for the serialization, the MemoryString length would be the same.
I'm working on a project to extract documents from a SQL Database and writing those documents to a network drive. However some of the files pointed at in the DB are encrypted files (RijndaelManaged)that reside on another network driveI have been able to retrieve, and decrypt the files using streams. Now aving problems saving or converting the Memorystream into an actual file.
Here is my code
Public
Sub ExtractDocument(ByVal ThisDocumentInfo
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I'm working on a project in VB.Net (2010) where I'm extracting files from an Document Management System.The Files reside on the network, and information about the files are in a SQL 2005 Database and have been encrypted with the Encryption Stream (System. Security. Cryptography. Rijndael Managed)i have retrieved the file, and decrypted them, but I'm trying to find out how to write the stream back to a file.I know the file type (which is stored in a SQL DB)I can't find a solution in any of the VB files or the MS site.
View 2 RepliesI am dynamically creating an pdf from a memorystream to a web browser, using itextsharp. It is called via https and it works in IE and Firefox but not Safari or Opera. I don't care about Opera but I do want it to work in Safari though. If I make the call with http it does work (creates the pdf) in Safari but not https
The error I get is The error is: unknown error (CFURLErrorDomain:303).
Ive a picture box on a webform. I want to load a picture into from a memorystream. The code im using :
If Me.ComboBox1.SelectedValue.ToString.Trim <> "System.Data.DataRowView" Then
Dim bmpTmp As Drawing.Bitmap = Drawing.Bitmap.FromFile(Me.ComboBox1.SelectedValue.ToString.Trim)
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What I'm trying to do is convert a tiff image to a gif and display it in a picturebox on a webform. The source file is deffinatly be found as the commented out line which saves the file to the c: drive works perfectly. However I cant seem to get the picturebox to load with the memory stream.
I have some trouble with loading a richtextbox from a memorystream.I have some data in a database table stored as a byte array, I convert it to a string and load it into a memorystream and then I want to load that memory stream in the richtextbox. The application breaks on
Dim tr As New TextRange(rtbTemplate.Document.ContentStart, rtbTemplate.Document.ContentEnd)
though.
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I wrote a piece of code that grabs a fileupload, puts it into a memory stream, converts the main pic, and thumbnail pic, then saves them as jpegs, then updates the database.
Everything works fine, except one little glitch. If the DPI is above 300 then the image doesn't save right. It get's pixelated and blury.
here is the code.
Dim fileLen As Integer
# Dim myStream As System.IO.Stream
# Dim ImgContentType As String
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I want to validate xml against XSD (VB.NET). My function look like this:
Private Function ValidateXML(ByVal xml As MemoryStream, ByVal xsd As String) As ArrayList End Function
How can I do the validation when my xml is a memorystream/stream (I use stream because I don't need to store the xml) and my xsd is a string (I get my xsd from a web servise as a string, and I do not need to store it in a file)?
I use WPF and my program has images in a DLL resource file. I have this well working way to read in images from disk:
Private Function GetImageFromFile(ByVal fileName As String) As BitmapImage
Dim buffer As Byte() = IO.File.ReadAllBytes(fileName)
Dim memoryStream As New IO.MemoryStream(buffer)
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Now, how can I get images in this MemoryStream-way from a DLL resource?
The basic problem: If I use simply the "bitmap.UriSource = whatever uri" way and load many images in sequence like an animation it builds up the memory. I tried with the above memorystream way and it worked perfectly fine, but then I store my images in a dll and I don't know how to do this trick. If anybody knows how to read many images from a managed dll without building up the memory
I converted a project from 2008 to 2010 to be able to use the TPL.I've updated the compile target to .NET 4. Everything seems good, including the .NET 4 specific TPL stuff...except that:[code]
View 7 RepliesI'm trying to loop through a collection object in vb2010.The code was originally used in Vb6 The book said that I needed to code a NewEnumerator method first in order to be able to loop through my collection. I coded the following:
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It gives an error for IUnknown, staging that IUnknown is not accessible in this context because it is a 'Friend'.In the line in the function I removed the Set since it's no longer needed.The error message for this line is '_NewEnum' is not a member of 'Microsoft.VisualBasic.Collection'What are these messages and how do I fix this in VB 2010?m_colCourse is not a system collection.
I am trying to work out a way to group a collection of items like an enum so that I can access them through code else where in my program. i.e I have list of items and sub items
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So one of my programs logged an error the other day that I am trying to fix. The error was Collection was modified; enumeration operation may not execute.To overly simplify my code, users can add or delete objects from the collection at runtime. In the background, on a separate thread, a process runs every so many seconds that syncs the data in the collection with the data in a flat file.
To avoid my problem, it seems the most logical to create a COPY of the collection at the start of my second thread's procedure, and run off of that.How do I do that?If I try to say something like.
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I have a callback function in a C+ dll:
<UnmanagedFunctionPointer(CallingConvention.Cdecl)> _
Public Delegate Sub DeviceDetectionEvent(ByVal YasdiEvent As YASDIDetectionSub, ByVal DeviceHandle As UInteger, ByVal param1 As UInteger)
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I have this code to attach an image that is saved in my sql database as an attachments (or can be embedded picture) to an email. It is suppose to be a signature for an Outlook email. So I am attaching it to the email. Here is my code. On the line myNewMail.Attachments.Add I get the error "Value does not fall within the expected range."
Globals.EmailSignatureImage.Imagecontent is Byte() I know it has the correct data in it, because I show it in a picturebox correctly.
Dim
contenttype As New Net.Mime.ContentType
Dim memStream As System.IO.MemoryStream
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The Clipboard class has very handy methods to check contents, like 'ContainsImage' and 'ContainsText'.How do I check if a MemoryStream contains an image or a text?
View 5 RepliesI trying to display image in picture box. The application have two part.First part is windows application, and second part is web service (asmx).This is the code for windows application:
Public Sub PrikazSlike()
Dim p As localhost.Service1 = New localhost.Service1()
PictureBox1.Image = Image.FromStream(p.PictureShow())
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I have this program that extracts ole objects from my access database and tries to save them as jpeg images. I keep getting an error on this line:
View 6 RepliesI'm trying to play music from a memorystream in a WMP control.I can succesfully stream music with MediaPlayer, but this is limited to .wav and can't pause and so.
Dim mPlayer As New MediaPlayer(entryBytes.ToArray())
'begin playing the file
mPlayer.Play()
Is it possible to load a array of bytes or a memorystream into the WMP control?
Is there something that needs to be done with the following code to release the memory it uses?
Dim objImage As MemoryStream
Dim objwebClient As WebClient
Dim sURL As String = Trim(m_StationInterface.PicLocation)
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The code is on a popup form that shouldn't ever get disposed. A new image is loaded onto the form every time it pops up. However, the process size for the application continues to grow each time it makes it through that code block.
I've tried objImage.Close() and .Flush(), objWebClient.Dispose(). The process size still grows by a good 4mb after every call. It's like the old image is kept in memory.