Stuck Trying To Create An Async Method
Oct 8, 2010
For the last week I've been trying to create an async method. I tried the MSDN article How to: Implement a Component That Supports the Event-based Asynchronous Pattern but it does the work in a method in the same class. The work I'm doing is a lot more complicated and is its own class. The problem I'm having is the class doing the work cannot post the progress or completion as the methods that handle this stuff is in the parent class.
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Nov 15, 2009
I have a method that is asynchronously called when System.Net.Sockets.NetworkStream.BeginRead completes.
skDelegate = New AsyncCallback(AddressOf skDataReceived)
skStream.BeginRead(skBuffer, 0, 100000, skDelegate, New Object)
In that callback method, I need to interact with the UI thread.
Sub skDataReceived(ByVal result As IAsyncResult)
CType(My.Application.OpenForms.Item("frmMain"), frmMain).refreshStats(d1, d2)
End Sub
This causes an exception after the method completes. (when End Sub is executed)
[Code]...
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Jun 3, 2010
I'm trying to write a 'developer friendly' wrapper for the Windows API EnumWindows - the problem is that the API uses a callback function that gets invoked on another thread, where as I want my wrapper function to simplify this and make it more useful by working like any other normal synchronous function and just returning a value.
Now if the API just called the callback once that would be fine, as I would just call the API and make the wrapper function wait until it got a signal from the callback function telling it to continue... but the API calls the callback function over 100 times (once for every window handle that exists). The biggest problem is that there is nothing that indicates that any particular call to this callback function is the last one, so my wrapper function has no idea when it is safe to continue and return the list of window handles to the caller.
The only solution I could think of is to do this:
1. The wrapper function calls the API and starts a timer that waits 2 seconds before it raises the Elapsed event. The wrapper function then pauses until it receives a signal (ManualResetEvent)
2. Each time the callback function is raised by the API on a different thread, it stops the timer (so this is before the 2 seconds have elapsed), adds the current window handle that was passed in by the API to the list of handles, then starts the timer again.
3. If the timer reaches its 2 second interval then it is assumed that we are at the end of the windows because otherwise the callback would have stopped the timer. So the timer's Elapsed event handler is what signals the original thread (that the wrapper function is executing on) to continue as we now have a complete list of windows to return.
This works fine and does exactly what I want... but I dont like it.
I dont like forcing the caller to wait an extra 2 seconds after the API has done its last callback but more importantly I dont like assuming that the API will never take longer than 2 seconds between callbacks. In reality on my PC it is never anywhere near that long between callbacks, it is something like 200 miliseconds, but I have no idea how long it would be on a slower PC and I want this to be completely reliable.
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Nov 25, 2011
I have a large problem with inheritance in vb.net. The problem is the following:
I have 2 forms => frmBase and frmChild
In frmBase i want to create a method Called StartWorking() and i want frmChild to inherit this method.
But here is the tricky thing: when frmChild.StartWorking is called i would like the following => without calling MyBase.StartWorking()
I want frmBase.StartWorking() to be executed first and after a test in frmBase.StartWorking if blnValue is true then frmChild.StartWorking has to be activated. if blnValue is false that frmChild.StartWorking cannot be activated.
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Oct 19, 2010
Consider a MyForm class that contains a shadowed implementation of Show(). It also contains a CreateForm() method, which accepts an instance of the form and calls the shadowed sub:
[Code]....
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Jul 10, 2010
I've got this code here, hard coded into a button. What I want to do is create a module with a method, let's call it "openFile."
That way, in the future, I can just call openFile("default directory",file type, etc etc) and also being able to set the input from the reader as the text in a text box or something all in one line of code. Is this possible? I don't know anything about writing modules or my own methods/API or anything like that...Can someone point me to a tutorial about this?
Here's the
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim filesOpen As New OpenFileDialog()
filesOpen.InitialDirectory = ("C:") 'set the default directory
[code]....
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Dec 30, 2010
i have a multi language website and i get the data from xml file now to make the code easier to use and if in future i add some more data to xmlfile i need to create something that be look like this:
Languages.Account.UserName() return a string "User name: "language.Video.NotFundError() return as string "Sorry, your requested video is not fund."
[Code]...
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Jan 25, 2012
There are two ways to create methods on the fly. Through Anonymous method and through Lambda expression (relevant for C# language as far as i know). Though there is not much difference between them. How to create Anonymous methods in VB.NET ?
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Apr 28, 2010
I am really trying to follow the DRY principle. I have a sub that looks like this?
Private Sub DoSupplyModel
OutputLine("ITEM SUMMARIES")
Dim ItemSumms As New SupplyModel.ItemSummaries(_currentSupplyModel, _excelRows)
ItemSumms.FillRows()
[Code]...
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Feb 8, 2010
I'm trying to change/execute the example [URL]...onContext.aspx I've posted my project below. I'm getting a cross-threading error and I thought the point of all of this was to avoid that. (yes I realize I could just delegate... I'm trying to do something more complicated but am using this as a test bed)
[Code]...
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Aug 21, 2009
I'm working through a book that does not provide a lot of example code and what it does provide is in C#. The book refs vs 2005 but I'm using vs2008. The author asks for the user to create a solution with two projects, one winforms and the other a class library (called DependentAssm). The class library is added as a reference to the winforms project In the class library, he asks one to create a new class called SayHelloComp. The project created a file called class1.vb, and a class called class1 which I renamed to SayHelloComp. I left the file name alone, that's ok right?
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Jul 24, 2011
I like to create an extension method to Image.FromStream Public Shared Function FromStream(ByVal stream As System.IO.Stream) As System.Drawing.Image
With possibility to cancel processing like Public Shared Function FromStream(ByVal stream As System.IO.Stream, ByVal CloseTask As ManualResetEvent) As System.Drawing.Image
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Aug 7, 2009
I doubt anyone has specific experience related to this particular task, but maybe you can spot my problem. I'm trying to make a call to lithium (forum software) to place a vote in their poll, and their docs show this:[code]I'm not able to successfully register a vote and they say it's because the poll.choice param is not appearing in the header, but if I step through debugging, I see it in the Header Keys/Items just fine.
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Aug 18, 2011
(New clsViewIllus).View(MyIBaseView, enumViewSolveTypes.View, Me, , True)
... in VB? Basically too lazy to do this:
Dim vi As New clsViewIllus
vi.View(MyIBaseView, enumViewSolveTypes.View, Me, , True)
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Oct 12, 2010
I want to create some reusable code in my forms.The idea is that a class is growing when more subroutines are added so, I need to store the finished subs somewhere to make place for others, this way I don't lose myself searching through the entire class
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May 17, 2012
i need to create a hash table using a multiplication method and i need to create an array of linked listso how i can to create array of linkedlist in vb or c# ?
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Jun 5, 2012
Is there a way to create a method with unknown number of parameters? And if it this the case: How is it possible to get access to them within this method? Do they have to be from the same type?
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Dec 28, 2011
how to create a save to text file method with a try catch in the method in a class and then call this save method from a button on a window form. I am currently doing the save method under the button directly but to tell you the truth i would prefer to just do it one time and call it from different locations in the various forms i have, then copying it all the time.
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Jun 18, 2012
I want to know how to create our own file, such as: (.Docx). If we opened the file in notepad the characters contained in the that's file could not understand, so i would like to know by what method of making the it's file? Is the file created and use encryption method or what?
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Aug 25, 2009
I am creating some Jpegs on the fly using the copy method within Office products. Effectively I am taking a snapshot of some tables in Excel. I know how to copy the data. I now want to store the copied data into files in a temp directory. How do I take the information which is now on the Clipboard and paste it to a file which can be saved in a temp drive?
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Feb 14, 2012
I'm trying to create an overloaded method in a module, but if I type Public Overloads Function GetData(ByVal sql As String) As String it tells me "Inappropriate use of 'Overloads' keyword in a module". Are overloaded methods not allowed in modules?
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Apr 20, 2012
I'm completely stomped with the payroll program I have created. The NetPay variable is stuck on 0 and I went through step mode to try and fix it. No luck so far. Additionally I'm trying to turn the whole numbers, that the users input into the form, into percentages(such as 10 into .10, 25 into .25 ect..). Tried 1/x and (x * 10^-2) [code]
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Dec 14, 2010
so i have a class called FOOTBALL,then another 3 classes/forms that inherit FOOTBALL, they control score (SCOREBOX), possession (POSSBOX), and quarter (QUARTERBOX).the FOOTBALL class has 4 variables, "score" (array of 2 ints), "teams" (array of 2 strings), "possession" (boolean), and "quarter" (int)after that i have another form called MAINBOX, which creates new instances of the 3 classes (SCOREBOX, POSSBOX, and QUARTERBOX) (like this: private scoring = new SCOREBOX)... however they all technically create their own FOOTBALL classes, so I cannot connect them.
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Oct 27, 2009
I'm writing this program in Visual Basic .NET to organize different fields of data, and I'm using profile slots through application settings to store the data for users. But, I ran into a stack overflow error in my SlotSelect.vb class. My best plausible guess for why this happens is that I'm using the wrong kind of variable container in the below sauce code, but my dilemma is that I don't know what specifically is going wrong.The code that the vshost is saying is the cause for the overflow was written from some code that I looked up on MSDN and other places for referring to objects in other classes, and I tried using other variants of it to see if it was any different. So far, nothing has worked, and it doesn't stop the error while compiling, much less in the code markup--it only catches it when it starts the application in debug after it finishes building
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Mar 11, 2010
i am using Visual Studio 2008 and VB.NET 2008 and SQL Server 2005 as the database. I just finished designing & writing codes for a customer's contract information and , however after it has been connected to the database only one of the datetimepicker can be click, (i put 2 datetimepickers to find date interval) and the rest of the function including in the form are not working! it seems that the form stuck and NOT responding. i cant even close the form using the X button, so i have to stop the process using compiler (visual studio 2008), however if i press the 'Delete' button before the 'Add' button, it will successfully delete the data..
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Feb 27, 2012
I've got one for you. I am working on a program that calculates the cost of a trip given a specific price of a Workshop say "Handling Stress for $595" the length of the workshop say "3 Days" and the city the workshop is in say "Austin for $95/day" now the issue i am having is that for example my NumDays variable (the variable for the number of days of the workshop) is not taking the value. Ive ran a Watch on the variable and it stays at 0. It also displays zero. i have assigned it an integer so it should be working if I assume correctly.
[Code]...
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Aug 12, 2010
The problem is that the code is in a loop which i'm not sure how to stop.The need the text file to read all the file extensions.So i start looping through all the files in a folder.The other problem that happens is that i also need to loop through all the files in the folder so that i can compare the string line and the string X. So the final result is that my program is in one giant loop.
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Sep 15, 2011
These are the instructions. Create a Visual Basic program that reads in baseball player information from a form and holds all of the player information for an entire baseball team (20 players). A baseball player consists of a first name, last name, number, position, and batting average. The form should contain 3 buttons Add Player, Display Players, and Exit.
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Dec 29, 2011
I'm a c# developer and have not enought experience in VB.NET.the scenario:
Namespace Presenters
Public Class BaseFooPresenter
assuming the public default parameterless constructor[code]....
I can create a method SetValues( ... parameters ... ) and call it from the two constructors but does someone knwos a workaround to avoid this error?, why the compiler do not validate the possibility to call the base constructor before the overloaded constructor?how to justify logically the fact that it's not possible to call the base class constructor and another class level constructor from one class level constructor at the same time?
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Mar 5, 2011
I wish to create a form with a translucent clientwindow but want to have all contained controls and the form border display as normal. Setting the form's Opacity level dims the entire form including its controls and this is not the effect I'm trying to achieve. I have achieved the desired effect by placing a second form behind the main form (with the main form's "TransparencyKey" property set) and adjust the background form's opacity level. This added a few issues to overcome in terms handling the z-order, handling click-through through the main form, and an additional form in the Alt-Tab sequence that I did not want.
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