I have an issue with usercontrols that has been puzzling me for a while. I think I must be overlooking something and many hours of web searching haven't resulted in increased insight.In my main program I have defined several events, that may be raised at certain times. e.g.: Public Event FlipBackgroundEvent As EventHandler
View 15 RepliesI have a winforms app and my code works fine.But I want to know if my code is bullet proof or if it only works without load.Let me explain it:I have a windows form where I have overridden the OnKeyDown method:
Protected Overrides Sub OnKeyDown(ByVal e As System.Windows.Forms.KeyEventArgs)
dim args as new ActionEventArgs(ActionType.Bark)
RaiseEvent Action(me, args)[code].....
Now I have a class that is registered to this event and, if it knows how to handle the ActionType it sets Handled to true.
Public Sub actionHandler(ByVal sender as Object, e as ActionEventArgs) Handles me.Action
If e.Handled then return
If e.Action = ActionType.Bark[code]....
I tried this code at my developer machine and it seems to work. In the OnKeyDown Method, everytime I query the Handled variable, my actionHandler method did run first.But I asking me if this is only the case because my developer machine is in idle state and the event queue is processed so fast or can I expect the
RaiseEvent(...)
method to wait until every registered EventHandler has finished it's taks?
I would like some code to execute at the "preload" stage of my usercontrol's lifecycle. However the preload event is only available on the Page object. So, I added the following method to my usercontrol:
Private Sub Page_PreLoad(ByVal sender As Object, ByVal e As System.EventArgs) Handles Page.PreLoad
However, I know get the compile error: "Handles clause requires a WithEvents variable defined in the containing type or one of its base types".
As the Page property is inherited from UserControl I don't see how this can easily be done.
I have an object that is defined as a global variable based on custom class. Within that class I have an event that gets fired a certain intervals. These events are fired on the same thread as where the object is declared. How do I create a global object, but have the events within that object fire on a separate thread?
View 2 RepliesWould I be correct in assuming that the following piece of code will release the resources for the SQL Connection within the SQL Command? [code] If I am calling this method within a try catch block, do I really even need the Try, Finally in the code above? [code]
View 2 RepliesWhen you declare a local variable (inside a method), is it automatically disposed when the method ends? Or should I still use variable.Dispose() ?
View 16 RepliesI place these 2 questions in this forum simply 'cause those that know GDI+ best are probably .Net vs. VB6 classic users... So here it goes.I'm using GDI+ flat file to generate a textured brush with image attributes. Creating these are no problem, but I can't find documentation that says whether disposing of the brush will dispose the original image & attributes handles I've assigned to the brush or whether I need to destroy those also? I can't locate anything that says whether GDI+ copies the handles or uses the ones I provided. Destroying the handles well before the brush is destroyed does no damage. Thus my assumption is that the handles are copied. But you know what they say about assumptions.
2. Likewise I use a GDI+ function to return the image assigned to a textured brush. Again, I don't know if that returned image handle is to be disposed by me or not. The returned handle changes every time I call the function, so I'm assuming that I should be destroying it. Thanx to all that can shed any light whether from personal experience or pointing me to some black & white documentation.
I have a number of UserControls that have the same event .
When I use an Object instead of UserControl, I can not use Addhandler.
Here is the simplest example of my problem: In this example error is "TextChanged is not an event of Object"
Dim obj As Object = TextBox1 AddHandler obj.TextChanged, AddressOf text_changed_event I have to use this structure, because in a FOR loop I use some different UserControls as obj. All UserControls have the same event.
Is there a way to use this structure without error?
Maybe there is a way to define a new object that covers all my UserControls.
I have a number of UserControls that have the same event .When I use an Object instead of UserControl, I can not use Addhandler.Here is the simplest example of my problem:In this example error is "TextChanged is not an event of Object"
Dim obj As Object = TextBox1
AddHandler obj.TextChanged, AddressOf text_changed_event
I have to use this structure, because in a FOR loop I use some different UserControls as
[code]....
I'm using a com object in my vb net application. I'd imported the com library and everything is fine.But the object does not raise events, None. I need to know if there is some way to achieve that it works.
View 6 RepliesIn a reply to one of my posts, a user said I should create an event for Textbox1.TripleClick.So, I would need to create an event.My problem is, how do I create an event for a textbox so that the event shows up in the textbox events?
View 10 RepliesI have a class that is used as follows:
Create an object
Run the RunIt method
The object runs some code and sometimes raises Event1 and sometimes Event2
I want to run that object using Background worker
Programming the app I wasn't sure of the code so I created the VS project shown below so I could make this post
Many questions:
Which routines in the code are run on the worker thread?
Is the object created on the worker thread?
And are its events run on the worker thread?
How to handle the Cancel. The way I did appears tp work except that
e.Cancelled does not return as true (Done is displayed).
And suppose the object didn't have events how would I handle Cancel?
Is there a better way to handle the basic problem?
I wish the code was shorter but wanted to be sure I prsented the problem.
Option Strict On
Option Explicit On
Imports System.ComponentModel
[Code].....
I have a custom datagridviewcolumn in which i've added an event.The problem is, I can't work out how to see who has subscribed to the current column object's event and add those subscriptions to the cloned column object.
I get around this problem by asking the calling program to pass the address of the handler to a delegate in the custom column, instead of adding a handler to the event.
I've been thinking about my options when it comes to events in vb.net.What I'd like to do is to track events that are fired in an application without explicitly declaring them with 'handles' sub. Here is a pseudo-[code]....
Yeah I know, not quite working, but is there any way of implementing something like this in vb.net? My end game is really to be able to monitor events fired in many objects from another object, isn't there a more maintainable way to do that then to add a special sub in each object that handles the event that I want to catch? I need some way to let one object handle events fired in other objects without a special sub, the AddHandler goes a long way, but I can't really use that dynamically like so:[code]....
Following up on my question yesterday to deepcopy an object with events in C# and attach the events of the original object to the Cloned copy is pretty easy, you just set the Event declaration in the Copy = the value in the original. Deep Clone when events are attached. How do you do this in VB.Net? (Using .Net 2). Maybe there was something with reflection where you can examine what events are bound and somehow transfer those to the new object.
View 1 RepliesI want to use One routine to handle multiple events & i want to give the list class object to the routine handle clause in vb.net. Is it possible? I have 100 buttons on my web page & i want to handle click event of each button. I have same coding on each button but the only difference is that, which button is calling the event handling routine. So i want to make one sub routine for handling event of all my buttons.
I can solve this by writing each button name in the handles clause like - Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ImgRCP_26.Click, ImgRCP_27.Click,. But it is so lengthy procedure. So that why i want to handle my button in the arraylist. How to do this?
I have a query about dynamically added controls to a form. I have a series of buttons which are created and added at run time. I have a two drop down lists and two buttons which are created at design time. Button 1 creates a series of buttons called "Test 1.x" based upon the selection of the two drop down lists. This works fine and am happy with the logic.However.... Button two should remove all the dynamically created buttons from the form.This does not happen. What does happen is that 50% of the buttons are removed starting with the first one. WHen checking the loop it only enters the loop half the amount of times that there are buttons. Very strange. When the loop is run repeatability it will remove all controls. Why will my logic not remove all the dynamically created controls at once? What is wrong with my logic?
I attach two code snippets and the .net file for your consideration.Button method which creates the dynamically created buttons from the two drop down lists and adds to form
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim Count As Integer
Dim MaxHours As Integer
[code]....
I was just wondering if there was a way that I could get the properties of each item in a sub that was linked using AddHandler.
As in, say I have three PictureBoxes that I created and added to a sub using AddHandler. How can I get each of these PictureBox's properties? (I'd imagine it would be using a For Each loop?)
I've written some code to handle an event as follows:
AddHandler myObject.myEvent, AddressOf myFunction
It seemed that everything was working at first, but when I ran the debugger, I discovered that oftentimes, myFunction would run several times each time myObject.myEvent fired. I figured out that I had allowed the code to add the event handler to run more than once, resulting in this behavior.
Is there a way I can do something like this?
If myObject.myEvent is not handled Then
AddHandler myObject.myEvent, AddressOf myFunction
End If
I'm using a TcpClient to try and connect to a server. I have the following code, which uses valid IP addresses and ports:[code...]
My problem is that the server I'm using is my own, and when I intentionally don't have it running, an exception occurs whenever I try to access any of TCP_SENDER's properties (in the example above,
the "SendTimeout" property throws the exception, but any other property has the same behavior). The exception thrown is "No connection could be made because the target machine actively refused it.
This exception is expected since I don't have the server running (and sometimes in real-world scenarios I won't), but the real issue is that the "Try/Catch" block I have won't catch the exception.
If I run the code above when the server is down, the "Catch ex as Exception" code is never reached; instead the program just throws the above-mentioned exception with its green font at the "Why can't
I catch the exception? Even if I give trash inputs to the system I should still be able to handle any exceptions that might occur, right?
Check out this code. Basically, the event frmStart.Next_Clicked() is not being handled in the class MappingWizard, and I'm not sure why.
CLASS MAPPINGWIZARD - To start the "Mapping Wizard", a new instance of MappingWizard is created and MappingWizard.Start is called.
vb.net
Public Class MappingWizard
Private WithEvents fStart As New frmStart
[Code]....
the procedure Start_Next_Handler() never gets called in MappingWizard when the Next button in frmStart is pressed.
I have a VB.NET application (VS2010, .NET 4.0) that seems to throw an exception under some unknown conditions after a number of hours. In addition to the main thread, there are additional threads running. In reading this link: [URL] it seems like this would be a big help in trapping this exception. I have what are probably some very basic questions:
1. I assume ErrorHandlerForm() in the example refers to the main form of the application, setup.vb in my case. Therefore the last line in the example should be:
[Code]...
I would have expected to to replace ErrorHandlerForm.Form1_UIThreadException with find a setup event such as Setup_UIThreadException but there doesn't appear to be sucn an event.
I set timeout for 30 mins in web.config like below
<forms name=".FormsAuth" loginUrl="/Login.aspx" timeout="30" protection="All"
slidingExpiration="true" >
<sessionState mode="InProc" stateConnectionString="tcpip=127.0.0.1:42424"
[code]....
Is it possible to catch the combined key presses of Ctrl-Alt-Delete so that event can be handled?
View 9 RepliesI am trying to add to items to a combobox by using the "enter" key. It does work when I add the first item, but if I manually clear the box and add another items it does not get added to the list.
(1) I click in the combobox and type "hello" and press the "enter" key
(2) I click on the dropdown arrow and see that "hello" is in the list
(3) I select "hello" in the box and erase it, item is still in the list
(4) I type "goodbye" in the box and press the "enter" key
(5) "hello" is still in the list but "goodbye" is not
Here is the code:
Private Sub CopyrightCombo_Keypress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles CopyrightCombo.KeyPress
If e.KeyChar = Microsoft.VisualBasic.ChrW(Keys.Return) Then
[code].....
if I comment the if/end if line and type "hello" the items added to the combobox list are: "h", "he", "hel", "hell", "hello" wich makes sens since the add items is run on every keypress? I know that my commands for adding items is good, I know that my keypress event is handled properly but not when I specify using the "enter" key.
I have an error with my Login.The Error show "the variable name '@Username' has already been declared.Variable names must be unique within a query batch or stored procedure.": this is my code..
[Code]...
I've developed program w/ VS 2005 .net 2.0.... the program works great on all my customers computers, except for one. Immediatedly whenever opening the program he recieves a clr20r3 error and the process terminates.
I compiled a version of the program that put a simple msgbox that displayed "I'm working right now" first thing in the sub that handles me.startup. The program doesn't even get that far. I've tryed repairing .net 2.0... and completely uninstalling 2.0 and reinstalling it.
I have 3 components, a managed .NET diagnostics app, which interfaces with a C++ multithreaded UDP socket messaging DLL, which sends messages to another C++ app.
Sometimes (especially on exiting the managed app) the messages are not getting properly handled by the destination app. The UDP socket DLL is sending everything fine, but they are not being handled on the recieving end. Now, if I put a messagebox in on the managed side, everything goes fine. Thinking it was just a delay thing with the popup, I've put thread sleep, regular sleep, timers, counting loops, etc. These "other" solutions do nothing, only the message box is making the messages be handled.
Since today VisualBasic 2010 express does not work any more: every time i try to run a project i got the following error:
InvalidOperationException was unhandled
Error creating the form. For details see
Exception.InnerException. Error: Exception thrown by a component outside.
[Code]...
I searched a few threads for TextBox number solution and found that most were using e.Handled and e.KeyChar in TextChanged. But I couldn't find them in VB 2008. What can I find in Vb 2008 for the same meaning?
View 7 Replies