How To Create Key Access For That Fast Array
Jun 19, 2011How to create Key access for that fast array in VB.NET [code] waiting for any sample, this sample fastest for me work, but retrieve by key not only by number.
View 6 RepliesHow to create Key access for that fast array in VB.NET [code] waiting for any sample, this sample fastest for me work, but retrieve by key not only by number.
View 6 RepliesI need a method of quickly searching a large 2 dimensional array. I extract the array from Excel, so 1 dimension represents the rows and the second the columns. I wish to obtain a list of the rows where the columns match certain criteria. I need to know the row number (or index of the array).
For example, if I extract a range from excel. I may need to find all rows where column A ="dog" and column B = 7 and column J > "a". I only know which columns and which value to find at run time, so I can't hard code the column index. I could use a simple loop, but is this efficient ? I need to run it several thousand times, searching for different criteria each time.
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What is the fastest way to convert a String into an array of Short integers representing the character codes?[code]...
View 2 RepliesAt my company we build a lot of small, administrative type databases generally used by a dozen or less users. We have thus far done them entirely in Access. I've been doing VB forever and would like to write nicer, rich UI apps using a VB front-end to and Access database instead, as I find Access apps clumsy to use; VB apps look better and have more UI options.
I've started to play around with building Data Sources, Binding Sources, etc. and dropping them on forms, trying to create something useful with as little code as possible. I'm just wondering what folks generally think of using this approach. Remember this is for small, not complicated db apps with few users.
I know in the VB6 world bound controls took some heat for being not worth the effort it saved you.Also, is there a good book on the subject that concentrates on creating VB/Access apps with minimal code?
Is there a way to create new mathematical equations at runtime? Obviously you can pass new variables to a given equation, but I need to make a new equation altogether (then give it variables).
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I've been trying to mess around with image recognition in C# for some time now. But to do that, I need acces to all the pixels in the bitmap individually. At the moment, I'm using getPixel and setPixel. It works, but it's VERY slow. Is there any faster way to acces pixels in a bitmap? Unsafe code maybe?
View 6 RepliesWhen you need to do random access to the lines of a text file, the regular solution is to put those lines in a list and access them in that list.But doing this if the text file is large creates a large memory overhead and may cause some memory stress on the application.This class maps the file and provide the ability to read any particular line in the file at a random position, without the need to read or put in memory any other line but the desired line. The only memory overhead involve is the 1024 bytes buffer of the base stream.Even if the file mapping can be a process that consume a noticable amount of time if the file is very large ( ~ 5 seconds for each 100,000,000 caracteres) , once the mapping is done the access to a particular line becomes instantaneous regardless of the size of the file. (The file mapping can always be done at a convenient time (ex when the process load) and can be done on a worker thread The class is base on a StreamReader to support the differents Text Encodings Example uf usage ( As I say, if the file is very large, dont do it like that, but declare the class at a convenient time)
Imports Reader = System.IO.MyStreams
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
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Using VB I can create and access a random "cell" in an array like so
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This was an experiment to see if I could create a fake array using generics instead of using an array. I decided to try it, because I may use it if I find any advantages to using it over an array. it works, I am just asking for a second or third opinion, have I screwed anything up, or is there an easier way to accomplish this? If I use it, it will be for a 2D game I am creating, and is used to draw the 2D screen graphics, placing an image based on what image identifier is located at what coordinates. The value stored in the fake array is an integer that disignates the graphic to draw and whether it is passible or not, i.e. 0 = a floor image, 501 = a wall image that is impassible (any image number > 500 is impassable) The Class definition:
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I have used VB (versions 2 - 6) through many years; however, I am crash-course training myself into the VB2008 / VB2010 world kicking a screaming. I would like suggestions as to what SQL database access method should I focus more on in my learning process without making me feel that I'm a million years behind. I know I have WinForms where I can create a datasourse and drag / drop fields or tables on a form to create a grid (not really what I'm looking for).
My trouble isn't so much designing the form but in how I access the database. Theres XML, LINQ to SQL, ADO.NET, and many other methods. Not only do I need to grasp these methods quickly but I also need to know what type of projects I should create. What I mean is...I was thinking that I would design a WinForm app; however, I see that there are WPF apps and others to chose from. This is getting deep. I know it depends on the project that I'm working on. My plans are to write an app based off of either an SQL Express 2008 or SQL Server 2008 database. This first app will be standalone for now but may later become multi-user. I know I'm far behind on my learning curve coming from VB6. I have read a bit on VB2005 / 2008 / 2010. I own
both VB2008 and VB2010. I use VB2008 at work. I know ADO.NET is still alive but by what I read online, it's a dying method and is only kept for backward compatibility. XML and LINQ to SQL and other methods are all pretty new to me.
I want to create an array of an array (or arraylist of an arraylist) to hold strings.I want to fill an array1 with string values Then add this array to array2. - but only taking up 1 row in array2 e.g something like array2(index)=array1 Then clear array1 then loop through this again with different data, and add it to the array2.so will end up with something like
array2(0)... contains a collection of array1 data
array2(1)... contains a collection of different array1 data
.. and so on
i think i need to make new instances of array1 each loop, but not sure.I dont mind if it uses arrays, or arraylists, or lists, or structure of arrayslists?
I've been developing a simple virus scanner and it works by reading the hex code of a file and comparing it to signatures from a database. Anyway, the only thing slowing it down is how it reads the hex. This is the hex reading part of my code so far:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles LoadFile.Click
Dim ArrayHold() As Byte
Dim Index As Integer = 0
Dim Str As New StringBuilder
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What I need is to highlight multiple matches within some portion of text as the user types a search pattern. Right now I'm using a RichTextBox to highlight text. The highlighting takes place if a user changes the search pattern and naturally it happens with each key press. It works, but I'm experiencing a performance issues. If the text is large enough the highlighting takes too long (up to several seconds).
Facing that I tried to launch the highlighting procedure in a different thread aborting it and launching it again if the search pattern was changed during the highlighting but still I'm not satisfied with performance. Now I'm asking if there some other control I could use to speed up the process?
Following is the code I used for reading the files and folders from a drive etc.
Public Class LoadingBox
Public counter As ULong
Public OpenRecords As New Dictionary(Of String, MainWindow.records)
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OK. I am making application for copying. Problem is that every time application wants to write it first tries to write via fast IO and get response that it isn't allowed and then it writes a file (i am assuming without fast i/o). I have no idea what fast i/o is (i know io is input output -> read write). So I can assume that it is handled by class that I am using to write. I am using System.IO.FileStream and its functions Read and Write. Is there any other class that I can use witch will allow Fast IO or disable trying it in first place (I would like the first solution)? Or should I do something else?
View 6 RepliesI need to transfer files from one server to multiple cients (using the internet) in the fastest possible way in .NET . What are the different types of transfer protocols which can be used in .NET or VB.NET so that the files are sent in a very short time ? I have tried using FTP, but that is slow because it requires authentication, handshaking etc. What i want to know is the options which we have in .NET for sending files in the fastest possible way between a server and multiple clients.
View 1 RepliesI have text file which contain the 15000000 Rows with the Comma delimiters..i want to import that file to SQL Table Through VB.net(2005) With 1000 Rows per seconds. Is that Possible through VB.net
View 2 RepliesIn a scientific application I'm writing (vb.net) I use a huge collection of object stored in a tree structure. Every object exposes a LastAccessed property (datetime) that stores the last time the node was accessed by the algorithm.I need to find a fast way to find the N least accessed objects in the structure.I'm using an algorithm like this (pseudo-code)
dim Olist as new list (of myobject)
....
array.sort(Olist,address of compareByDataReverse)
for index=0 to N-1[code]....
I'm sure there is a better way to do that because the list is normally huge ( consisting of more than 10^6 objects).
I have a number of user controls (about 200 user controls) which I want to display on the screen (which the form will scroll).
What is the quickest way of running / opening the page?
would you add the user control on the page during design mode or do it during runtime?
It will also get settings from a XML file like names ect.
I m inserting 30 to 50 records .then set table as datasource to report.It takes 5 minutes.Plz anybody tell me how to do it fast.Then my pc is hangedI have also tried adding datarows into datatable instead of inserting records into access database and set datatable to report.but same time cosumed.
View 1 Replies I need to implement a fast FIFO (First in First Out) buffer which has a fixed size (so data effectively falls out the end, much like a shift register) for a DSP (Digital Signal Procesing) Filter i have written. My question is there any faster way of doing the buffer other than as follows: _
'-- FIFO Buffer
Private Inputs As New List(Of Double)
For i As Integer = 0 To Data.Length - 1
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I'm recreating an old 16 bit game. I'm creating the chat normally displayed at the bottom.Each sentence transitions in character-by-character.Every time a character is added, I wanted to have it make that little bleep noise. I've got a wav file that contains a short 'blip' that sounds just right, problem is, when I have it do the blip every time, it usually messes up.
View 1 RepliesI found the below sample to retrieve webpages. I need to request a lot of pages from the same website which requires authentication. Because there are a lot of pages to retieve I like to speed up the requests and like to avaoid to send the credentials and also the certificate. Is it somehow possible to stay connected?
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I have written a logon script using Visual Basic Studio Express 10 and it simply installs printers and adds network shared drives. It does look at the users Active Directory group and add drives / printers. But on occasion it doesn't install the drives or printers.
I've placed a copy of the logon exe on the desktop and if the user finds they are missing drives etc they click on this and add them again. This has never failed so I'm curious as to why exactly the same exe would fail at logon? Is it something to do with speed of the computer or a time out somewhere? A frustrating problem!
I tried to initialize an array in a Public Sub, but then when I try to access the array's value from Button1 click event, it shows blank.
Public Class Form1
Public myArray()
Public Sub SimpleArray()
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Ive tried making my own array, and ive practically completed it, but it doesnt seem to work. The issue seems to be that it cant convert string to type double. but do not know how to fix the error.[code]...
View 11 RepliesI have this:
vb.net
Private Sub doWork_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles doWork.Tick
Me.doWork.Stop()
For outer As Integer = 0 To Me.queriedDGV.Rows.Count - 1
For inner As Integer = 0 To Me.hebdataDGV.Rows.Count - 1
Application.DoEvents()
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It works fine when I step through it with F8, but when running normally, I guess it's going so fast that I get an Index out of range when the outer For loop increments to the second iteration. I tried putting a timer in there to give it a chance to update the UI, but that didn't work. I also tried "Application.DoEvents" as a last resort, and that didn't work either.
I have an operation that will be performed MANY times and so I need it to be as fast as possible, thus I think keeping validations to a minimum is important here.I'm given an image, an offset and a size; and the idea is to take the color that appears the most within the area determined by the size and offset, so far I have this:
Private Shared Function someFunction(image As Bitmap, offset As Point, sampleSize As Size) As Color
Dim pixelsColors As New List(Of Color)
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I have a bundle of tiny pictureboxes on a form. The number is specified by the user, but it could be up to 100, or so. The user can select any set of these pictureboxes by a variety of means. I want to change the image to show the selection state of the pictureboxes, and I'm looking for the best way to do that. The pictureboxes each shows a bitmap. The brute force method would be to have a selected image and an unselected image and just swap them, but it seems like there ought to be a way to do something significant and reversible to the image, such as inverting the colors, that might be smaller that having a second copy of each image.
View 5 RepliesI have a coma separated text file with loads of records. Usually when we read a text file we start from the first line and go towards the last. I know that there will be x comas per record.But I want to start reading from the last line and then towards the top. This enables me to stop before I reach the top (depending on the data).
What would be the fastest way to read a text file in VB.NET?. I am using VS2008. Basically I want to read from last line and go upwards and stop when I want. I may not need to read the entire file.
[Note: I want to store data in an array and not show it in some textbox]