Protected WithEvents gel As New TabPage
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
TabControl1.TabPages.Add(gel)
gel.Text = ("Gel")
Private Sub Gel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles gel.Click
MsgBox("test") So my problem is that if I click on the tabpage gel, nothing happens.
Can you raise events from a class that has only shared members and doesn't get instantiated? I originally had the class members non-shared and created instances of the class where I need them. I had the events being raised and everything worked as expected. But as the class members are actually application level and do not need instancing, I converted all members in the class to shared so they could be accessed from anywhere in the program without creating an instance of the class. But WithEvents requires the creation of a class instance. I've done that and it seems to work fine when using an instance. And since I need the events handled in only one class, I can create the instance in that class and let all other areas access the class directly, without creating an instance.
View 10 RepliesI'm using Try/Catch blocks for a program calculating payroll and commission. I've dim'd my variables, and I've parsed them inside my Try/Catch blocks. It appears as if my Try/Catch blocks have been coded correctly. However when in run-time, my format exceptions will show regardless if I provided a correct input.[code]Is there an issue with my programming? Or could there be a property I'm over-looking for my text boxes? I'm stuck.
View 5 RepliesExperiencing error handling although no input errors?
View 3 RepliesI'm have a quite big application which have 2 serial ports and access 1 DB (running on Background workers). I'm experiencing some random locks while the application is running and I started looking for something that could cause it. One of the obvious possibilities would be if I had in the GUI thread some While_End that would never return.I have one While_End in my GUI thread but IMHO it does not look like it would lock, so I want your opinion: Does the code below looks like will lock?? If 'yes', Why ?
[code]...
Does anyone can imagine a scenario where this While_End would not return ?
In Global.asax, is there a way to handle SQL Timeouts elegantly, and display a message on the requesting page explaining the error? I know Global.asax has the Application_Error and Error events, but I'm not sure which (if any) I could use to accomplish this.
Related, can I access the page instance which raised the error that Global.asax is handling?
Who knows, why in vb.net WinForm projects the designer by default use the Friend WithEvents attributes and in C# - private ones.
By ex, in a form.designer.
.cs
private Label Label1;
.vb
Friend WithEvents Label1 as Label;
For WithEvents is more or less clear(for using Handles, apparently). But why Friend in VB and private in C#...
i have the folowing co
For x = 0 To 7 Step 1
For i = 0 To 7 Step 1
Dim rectangleShape1 As New Microsoft.VisualBasic.PowerPacks.RectangleShape() 'create a new object to assign to the array location
board(x, i) = New Microsoft.VisualBasic.PowerPacks.RectangleShape() 'create the new object in the array
[code].....
When you declare an object 'WithEvents' and then utilize the "Handles" clause at the end of your event methods, how does Visual Basic manage a reference change for the object? In other words, if the withevents var is set to ObjectA, then later I switch it to ObjectB (or nothing), does Visual Basic automatically both remove those handler methods from ObjectA, and attach them to ObjectB? Or do I still have a ObjectA's events being handled behind the scenes?
I ask this because if instead you use AddHandler for an object, and then switch your reference, unless you removed the handler before switching, your original object is still handled (at least I'm pretty sure that's how it works).
I have the following classes: Public Class Email
[Code]...
If a create a wrong email lets say "email" the exception is correctly cached and a message is showed however is i input a valid email the event is not raised, the object is being created but no message is shown and no error or exception is thrown i suspect it has something to do with using "myemail = new Email(email)" but i have seen examples of using new with withevents with no problem.
Does anyone know why a local variable cannot be declared WithEvents?T
View 3 RepliesI'm trying to create multiple instances of a child form. This form has an event that feeds a string variable back to the parent so I'm declaring it with WithEvents which is declared outside of the Sub - meaning multiple clicks will not open multiple forms.
another method of doing this while keeping the event?:
Dim WithEvents FRestoreDB As New FormRestoreDB()
Private Sub BtnOpenDB_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnOpenDB.Click
[Code].....
Is it necessary to set to Nothing(in Dispose()) all WithEvents fields?
Apparently Handles keyword adds handlers to such fields, but does not remove it until this field is not Nothing, and this can generate memory leaks?!.
This should be specially actual on cases like
class Foo
{
Private WithEvents _bar as Bar
[Code].....
I have an application that performs a lot of busy work. All of the work is performed using a BackgroundWorker and the point of execution is the DoWork Event of the BackgroundWorker.On the UI thread, before the workload begins, I display a PictureBox that contains an animated GIF that illustrates progress; for the most part this works fine and the UI thread is not paused or slowed while the BackgroundWorker does its job. There is however, one instance where the UI thread is impacted by the work being done and it defeats the whole purpose of putting this work in a separate thread. In this application, the user must wait until the work completes before they can move to the next step, so my sole reason for moving this all to a BackgroundWorker was so that I could display a smooth, uninterrupted progress indicator on the UI thread while this work was being done, so that the user could see that something was happening.
The case where the work being done is impacting the UI thread (pausing/delaying the PictureBox animation) deals with a referenced COM object.
[Code]...
All of the COM object event handlers and subsequent functions are appropriately using Delegates, but I am not sure why the ProcessFiles method would cause the UI thread to hang while the work completes; I thought that was the whole purpose of the BackgroundWorker.
I'd like to create an array of objects with events. Where do I need to put the "WithEvents"? Should it be placed in the ReDim line or the next one?I'm trying to use a "global" event, like objects of people that recieve a time-event to get older.
[Code]...
What is the optimal approach to a WithEvents Collection - VB.NET?Have you any remarks on the code bellow (skipping the Nothing verifications)?The problem is when I obtain the LinkedListNode(Of Foo) in a For Each block I can set myNode.Value = something, and here is a handlers leak...
-Could I override the FooCollection's GetEnumerator in this case?
-No. :( cause NotInheritable Class LinkedListNode(Of T)
Class Foo
[code]....
The vb.net "WithEvents" syntax is very useful, but if a WithEvents field which references a long-lived object is not nulled out, it will often constitute a memory leak.Is there any easy way for a Dispose routine to have vb.net automatically clear out all WithEvents fields and unsubscribe them?
I've figured out a nice way to wrap the creation of disposable fields so that they will be automatically Disposed when the containing object is disposed, without having to individually list such objects. Is there any way to take care of WithEvents fields without having to manually null them out in the Dispose routine?
EDIT:Since there was no response indicating a built-in way to do it without reflection, is there any built-in means of using reflection to determine whether a particular property is a VB automatic implementation of a WithEvents "field"? I know that a WithEvents "field" called "foo" is implemented as a property called "foo" and a field called "_foo", but that's such a common naming pattern that I wouldn't count on it. Is there some attribute that could be used to determine which properties need to be auto-nulled?
Public WithEvents Tree as Tree. I am not able to Serialize the Tree class, but if i remove the "WithEvents" keyword, it works fine. Why? What should I do if I have to declare it with "WithEvents"?
View 2 RepliesI have done an extensive search before posting this question, using many different search parameters without success at finding an answer.Using Visual Studio 2008 Express VB:My program requires a notification when a wav file has finished playing, a media player song list will not suit my needs.I have used System.Media.SoundPlayer, Microsoft.DirectX.DirectSound and My.Computer.Audio.Play to play a wav file. All work well at playing and stopping the requested wav. So far, I have not found a methode to capture an event when the wav has ended. DirectSound stops playing when the form has lost focus, so I dont think that I can use it. Audio.Play AudioPlayMode.WaitToComplete only holds up other operations and I dont want to create multiple threads.
View 3 RepliesSo I wanted everyone's opinion on this and what you think of this. Using the WithEvents modifier makes life very easy in VB.Net (srsly, I love it), and I was exploring some of its limitations and noticed you can do something along the lines of this:
[Code]....
I have to create multiple child window each embedded with dsoframer activex control,
Like,the following,
Private Function add_activex_control()
...
[code]......
Is WithEvents & Handles usage preferable to RemoveHandler & AddHandler?
From Memory point of view (remove an added handler after utilization, etc.)
I need instructions on how to install a 'WithEvents' into a sqlsever web form, read Server Error message:Description:An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately.Compiler Error Message: BC30506: Handles clause requires a WithEvents variable defined in the containing type or one of its base types.
[code]....
I must say personally, the WithEvents system is, shall we say, open to extreme false sense of security, so to speak. I like a lot of automation in my code, and tend to provide ways to do things manually, with a "default" behavior encoded. However, as I have just discovered, the withevents doesn't HOOK the event delegate until after creation. So even when you do New MyObject(), if an event is triggered during the Sub New() process, the delegate hasn't been assigned yet, and thus the event (which in my current situation is extremely important) never triggers. which begs the question the point of the WithEvents other than removing "AddHandler" lines from procedural code. Sure it saves on typing, due to code completion, but if that's it, that isn't much of a benefit. One would think that using the WithEvents would allow me to do:
PUblic Sub New()
MyBase.New()
RaiseEvent MyEvent()
End Sub
Tragically, this does NOT work, which royally screws up my lazy loading techniques and other such tricks that were supposed to make my code simpler to use, and instead has made things 10 times more complex, as I have to specifically alter class initialization sequences to be outside of class instantiation. (which should be one in the same, imho).Jaeden "Sifo Dyas" al'Raec Ruiner
"Never Trust a computer. Your brain is smarter than any micro-chip."
PS - Don't mark answers on other people's questions. There are such things as Vacations and Holidays which may reduce timely activity, and until the person asking the question can test your answer, it is not correct just because you think it is. Marking it correct for them often stops other people from even reading the question and possibly providing the real "correct" answer.
i'm a .net programmer, using .net framework 4, and i have a question about WithEvents clause. [code] Private Sub mylist_AddingNew(ByVal sender As Object, ByVal e As AddingNewEventArgs) Handles mylist.AddingNew..i get this error: Handles clause requires a WithEvents variable defined in the containing type or one of its base types.I think the problem is my custom bindinglist class....but how can i solve this?
View 8 Replieslistbox control (lst_tpAccount_AvailableAccounts) has an event handler:
Private Sub lst_tpAccount_AvailableAccounts_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles lst_tpAccount_AvailableAccounts.SelectedIndexChanged
[code].....
So I have a custom control that when added to a form will create two child controls inside it. The custom control's designer handles the creation of these. The problem I am having is that when the designer generates code for these controls only the parent control is declared "WithEvents". So my que
View 9 RepliesI am trying to do the following:
Public WithEvents frmButtons(999) As Button
And then use it like this:
Private Sub frmButtons_Click(ByVal sender As Object, ByVal index As Long) Handles frmButtons.Click
Where the index variable has to represent the object in the array like this:
frmButtons(index).Text="..."
But it gives me an error:
'WithEvents' variables cannot be typed as arrays.
I get the error on this line on [ListBox1]
[code] Private Sub ListBox1_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs) Handles ListBox1.SelectedIndexChanged
error
Quote:
Handles clause requires a WithEvents variable defined in the containing type or one of its base types.
I've got a TEXTBOX called CompanyName. And I've got a warning in the error tab that says:
WithEvents variable 'CompanyName' conflicts with property 'CompanyName' in the base class 'Control' and should be declared 'Shadows'.
Is CompanyName some kind of reserved keyword? I'm getting the same error for a textbox called Location. Can I ignore these warnings or must I rename my textboxes. My problem is the textboxes are named to match columns in a DB TABLE to allow me to do some auto-binding logic.