Use Of A BackGroundWorker - Calculate One Cycle And Then "hand-over" The Objects Back To The GUI?
Jan 7, 2011
Im building an application which has severals objects that are moving on a map.I think the calculation of this movement should be done using a BackGroundWorker thread. However the actual position of all the objects should be visualized on the MainForm after each calculation-cycle.The calculation should be done continously in the BackGroundWorker-thread (unless stopped by the GUI).So far I initialize all the objects within the GUI-thread.Is it possible to do such calculations on the objects using the BackGroundWorker-thread although they are "owned" by the GUI-thread?Or do I have to "hand-over" all the objects to the the BackGroundWorker-thread, calculte one cycle and then "hand-over" the objects back to the GUI?
I've started working with the backgroundworker class to try and keep the UI responsive while I make some expensive API calls. One of the API classes (details here[msdn.microsoft.com]) has its own event handler which I am using to update a progress bar in a small form that pops up. So I'm looking to use the PublishPackage command in a bgw thread and update a progress bar on the UI thread by using the ProgressHandler method.
I have an object of type Dictionary(Of Int16, Polygon) and which contains sometimes up to 15 or so Polygons that i am creating bitmap files with the Polygon. This can take like 20 seconds sometimes so i was trying to pass the full Dictionary to background worker as an argument but i get an issue when trying to access each individual Polygon inside of the Dictionary because the Polygons still belong to the UI thread. How can I access the Polygons inside the Dictionary with the backgroundworker?
Dim worker As New BackgroundWorker AddHandler worker.DoWork, AddressOf MeasurePolygons AddHandler worker.RunWorkerCompleted, AddressOf WorkerCompleted worker.RunWorkerAsync(PolygonCollection)
that is how im calling the thread. PolygonCollection is the Dictionary(Of Int16, Polygon) that contains all the polygons that i will be creating a bitmap file out of.
I'm working with BackgroundWorker, I want the BackgroundWorker do the retrieval process of data from database while the user can still do another task on the form. The problem is, after retrieving the data, I can't seem to access the ListView in my Form from the DoWork event of BackgroundWorker, I will populate that ListView using the data I've retrieved.
Consider this example, this is how I'm doing it:
Public Class Test Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
I am trying to calculate the number of years for my calculate age event handler, however i am apparently missing a method or whatnot because im trying to calculate the age , can anyone suggest help on this. I need to subtract years to get my age but when i try the birthdate.Subtract (currentDate) method i get an error about not able to convert from LONG?
So below is what I have.
Private Sub btnCalculateAge_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculateAge.Click Dim currentDate As Date Dim BirthDate As Date Dim Age As Long
I tried "PictureBox1.Cursor = Cursors.Hand" but that isn't what I'm wanting... I want the hand that "grabs" when you click. You can find it in picture editors and such. The "Cursors.Hand" just points.I'm sorry if I misspelled something or my grammar is wrong, I've never done well in those subjects.
I have been a programmer for almost 14 years and have worked in SQL, VB, VBA and MS Access. I am making the transition to VB 2008 and as you can imagine, it is frustrating. One of the new things to be in VB2008 is working with data. They have made it easy to setup datasets and output data to a form. In VB6, I never used the GUI data tools, I always custom programmed recordsets and wrote loops to output the data. Then, I wrote my own code to update, insert or delete the data. With VB 2008 I dont have to do this anymore, but is it a better practice to hand code than rely on wizards.
I also noticed I don�t have as much control over the data with using the wizards, for example. There is 1 insert statement defined for a table adapter. Lets say I wanted to perform a slightly different insert based on a condition. I can�t do that anymore right?
I need to draw free hand on a form i know how i can change the colors buts its just the drawing part. i also need it to save and load how would i do this ive been searching but nothing.
was wondering if you could give me a hand and point me in right direction with the project i am creating. It is a toolkit They are 2 problems that i am having wondering if anybody knew the issues
1. The textbox is not having them 1 by 1 for example
service pack 2 service pack 3
2. The other problem is a bit more tricky, I have software on the hard-drive c:directorysp2
it has to be implemented into the toolkit anybody have any ideas how without a database if possible. I thought this could be done in the load form, pre-loads the software and then checks when comes to installing the software in the list.
I'm trying to print out some arrays of data, arranged in columns, but am having a few problems:
1) I don't think that I'm calculating the x coordinate correctly for each column
2) The text won't right hand justify
Sometimes, I get the code fairly close to working, and then make what I think is the final change, but it seems to make other things worse. I'm a hobbyist,just learning VB for my own use, so I know that my code won't bring tears of joy to a professional..[code]
We are working on a poker game as a class project. My part is to evaluate and then determine the value of a players hand. We are evaluating from highest to lowest (ie. determining whether the player has a straight flush, 4 of a kind, full house, flush and then going all the way down to a high card only "worthless hand"). My part is evaluating the 2 pair, 1 pair, and nothing hands. The hand will be a two-dimensional array with the row(0 thru 12),column (0) containing the numeric "face" value of the cards and the column(1) containing the value assigned to the suite (1=clubs, 2=diamonds,3=hearts,4=spades). I have NO IDEA where to even begin this evaluating procedure.
Just had a question regarding a Windows Form Application in Visual Studio 2008.I was wondering if it is possible to have a RichTextBox and have a < (previous) and >(next) button. When the user selects the Next button, a new blank RichTextBox will be displayed, when the user selects previous button, the prevoius RichTextBox w/ whatever text was in there before will be displayed.
Is there a method to swap the left and right hand sides of a set of expressions in Visual Studio? I have a decent sized set of data that needs to be stored in an active record. In order to pre-populate the form fields on the page, I have already written the following [Code]
Is there some sort of the method (built-in functionality, macro, etc.) that I could use to swap each side of the expression such that the data is saved into the active record as opposed to read from it in order to perform a database insert? For example, after highlighting the above code and running the macro, it would become:[Code]
Since the number of columns in the database that this active record encapsulates is rather large, it seems like most of this typing could be avoided with a simple automated process. Obviously this wouldn't work 100% because sometimes there would have to be type conversions (e.g. int to string) but for the most part I think this would save a lot of time.
I am trying to get some data in DataGrid from XML files. I am reading that XML data and putting that data in DataView and giving that DataView as DataSource to DataGrid.As i have a schema for my XML, i dont even give HeaderName as system automatically takes HeaderText as whatever is in XML Tags. Now my problem is Pagination alignment, i have pagination on my DataGrid but even setting
doesn't bring pagination to extreme right of datagrid, rather it brings pagination on right of first column of datagrid(my datagrid has 9 columns) see attached pic
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load 'Bind data to Grid BindGrid()
In Visual Studio 2005 Visual Basic, I want to create an exe (without any forms) that will cycle through each file in a folder. I have not found any method of cycling through file names in a folder.
Now what I am trying to do is to find cycles in my graph. I have a user drawn graph using lines. Now what I want is to find out if any cycles exist in the graphs. My idea is to find a way to recognize a closed shape and then fill it in. I get this idea from ms paint , where if you draw shapes, the lines must intersect each other and form a cycle for the color to be in.
I am familiar with the VB6 ADO way of dealing with SQL queries and looping through the record set results.
However, what is the correct way to query a server, cycle through the results, and dispose of my query in VB.Net? All the ways I have been using seem to be unstable and crash randomly.
I have been using the following code:
Public Function GetSQLTable(ByVal strSQL As String) As DataTable Dim table As New DataTable Dim adapt As SqlDataAdapter
I want to add cross button image on the right hand side of tabPage.I m creating tabpages at Runtime.Mine code is added image to the left...I want to add it to the right....I m also adding text to the tabPage.& second Probs is dat..On button click suppose i add the first tab Page,Image is aded to the first Tab Page...When i click on button to create the second Tab,Image & text of First Tab Page is clear & so on.
I'm writing an vb.net application so that the user can type text to be added to a website. I'm using a richtextbox and I've added the facility to hyperlink selected text. This all works, but when the mouse cursor moves over a hyperlink it changes to a hand; how do I stop it doing that? It's confusing for the user as it looks like clicking the link will do something and it makes it awkward to correct spelling within the text of the hyperlink.
1) How do I force a form to open in a certain position on the monitor? ie. by default it starts in the top left corner of the screen. I want it to open in the bottom right corner. Also, is there a way to do this as a % rather than in pixels? As I want it to be in the correct position regardless of the resolution being used.
2) Can you remove the "x" close button on the top right hand corner of a form? If you can't, is there a way to disable it?
