I ma using DevExpress controls (which doesnt matter for this example). I have a lookupEdit control and I never want the EditValue_Changed event to fire. Can I use RemoveHandler to do this? If so can someone give me a code example of doing this? Should I put RemoveHandler in the load event of the user control I am creating? Or does it go in the EditValue_Changed event of the lookupControl?
View 3 RepliesI want to after clicking on button2,after that if i click on button1 then msg is not displayed Public Class Form1 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
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Some controls are dynamically created within a panel. Their event handlers are attached
Dim btn as new system.windows.forms.button
with btn
'set properties
[Code]....
I have a TableGridLayout (6 x 6) which host 36 buttons created at design time.From the 36 buttons, only a handfull maybe needed at anyone time depending on data retrieved from an SQL database.Everytime I need to 'clear' the grid to populate with new items, I clear the text of each button, make it visable if required and then upadate with the new text.On every pass if a button becomes active, I add an event handler to the button like this.[code]...
View 4 RepliesI'm writing a small 2D engine that uses Lua to control it. I've been setting events up in between the Lua and the VB.net for the past little while here. The problem, I've realized, is that is that I can't seem to remove the events which is screwing up quite a few things (because they are being called when they should be done with). To fix this, I wanted to add some kind of way to remove the specific event handler.
I know how to add an event handler:AddHandler Button1.Click, AddressOf Button1Clicked
But with this in mind, is their a way to remove a specific event handler in the VB.net? I didn't explain this very well: If I have this:
[Code]...
When I've used the remove handler method in my code, I get this warning:The 'AddressOf' expression has no effect in this context because the method argument to 'AddressOf' requires a relaxed conversion to the delegate type of the event. Assign the 'AddressOf' expression to a variable, and use the variable to add or remove the method as the handler.Why do I have to assign the "AddressOf" expression to a variable?
View 6 RepliesI have a Timers.Timer called COMTimeout, to which I add an event handler using:
AddHandler COMTimeout.Elapsed, AddressOf TimeoutEvent
however, the handler may also be:
AddHandler COMTimeout.Elapsed, AddressOf SecondTimeoutEvent
I now need to remove the handler, is there a way to do it without knowing the name or do I need to keep track of which handler as been assigned?
VB.NET RemoveHandler & Anonymous Methods
If I add an event handler like this:
AddHandler s.Click, AddressOf Panel1_Click
How can I can then remove the event handler?
Private Sub Panel1_click(ByVal sender As Object, ByVal e As System.EventArgs)
' Remove code
End Sub
How to remove a handler set up by a lambda expression? According to this MSDN article, lambda expression should be assigned to variables which should be used to define handler operators. So far, I have used lambda expessions w/o variables.
For instance, the following works:
Private Sub ScaleObjectInit1(ByVal objSrc As NumericUpDown, ByVal objTgt As FrameworkElement) ...
AddHandler Me.upDnScale.ValueChanged, Sub (sender As Object, e As Object) ScaleObject1 (sender, e, objTgt)
End Sub
Private Sub ScaleObject1(ByVal sender As Object, ByVal e As Object, ByVal objTgt As FrameworkElement)
[Code] .....
I am having a problem with the cellvalidating event constantly firing when the datagrid is refreshed (since the trigger that fires the event is the originally selected cell losing focus).I would like to remove the event handler for this at certain points of my code so that it does not fire but the examples I have come across on MSDN don't appear to do anything, so I guess I must be doing something wrong.[code]
View 1 Repliesto know if a control have any handler. I have a dgv and in the editing control Showing event i add an event handler like this: VB AddHandler e.Control.KeyPress, AddressOf Grid_KeyPress_NumbersOnly This event it's added in some of the columns and for the other ones i remove it... The problem it's when the user, for example selects 3 columns where the event it's added, then if the user selects one where the event it's removed, it doesn't remove all handlers... So i have 2 solutions, when removing i put multiple removes or the other check if the event handler it's added doesn't add again. I prefer this second option, but i don't know how to check if the event it's added?
View 3 Repliesremove an event handler from within the event handler?
I have a class that gets data from a hand scanner. When the scan is complete and the data is validated, the class fires a custom "ScanComplete" event and returns the data in a custom EventArgs.
In the calling program, I'm creating an instance of the scanning class and adding a handler for the "ScanComplete" event. In the event handler I get the data that was scanned and then remove the handler.
It seems to be working but it feels wrong to remove the handler while I'm running inside the handler. Will this cause a problem?
I am having some trouble understanding the different aspects of Event Handling. Of course, I know how to use "WithEvents" and "Handles". However, I have created some interdependent Custom Cotrols. I will try to describe this, and then post some code.
Assume a Custom Control 'GroupedListHeader", an instance of which is created by, and added to the controls collection of another Custom Control, "GroupedListNode".
GroupedListHeader adds an Event handler "OnHeaderClick" During initialization which hanndles several different events. As part of the handling in "OnHeaderClick", GroupedListHeader raises one of several Events which GroupedListNode in turn handles, again by using "AddHandler" during initialization. And so on. The events can propegate up through a chain of sub-components of my final control. I understand that I am supposed to use "RemoveHandler" somewhere, at some point, when I use "AddHandler". This is where my questions arise.
A. In the cases where I have used "AddHandler" to handle a custom event sourced by a sub-component, I get the following Waring:
Quote:
Warning2The 'AddressOf' expression has no effect in this context because the method argument to 'AddressOf' requires a relaxed conversion to the delegate type of the event. Assign the 'AddressOf' expression to a variable, and use the variable to add or remove the method as the handler.C:Documents and SettingsSuper God-like UserMy DocumentsVisual Studio 2008ProjectsGroupedListControlTestAttributesNode ComponentsGroupedListNodeBaseII.vb27446GroupedListControl
I am not quite sure what this is about, other than it seems to relate to trying to Remove a handler which is referencing another Custom Event.
An Example (The two in red are the source of the Warning): 'Added during the Constructor Method, after "InitializeComponent and some other Drawing-related Stuff:
AddHandler moTGHeader.Expanded, AddressOf Me.OnExpand
AddHandler moTGHeader.Collapsed, AddressOf Me.OnCollapse
AddHandler moTGHeader.Selected, AddressOf Me.OnSelect
[CODE]...
I should note futher that the component indicated above further propegates these handled Events upward to the parent of this component, where again, the same issue exists. What is it that makes the two items in red different from the others that they would cause this warning? How critical is it that I use "RemoveHandler" in this context? These events should persist until the control goes out of scope. Also, this is just an example; at several other levels in the hierarchy, I am doing the same thing. My understanding is this can result in objects retaining references to the Handlers(?) or something like that.
How do I get a Event Handler to fire from within a nother Event Handler?
View 6 RepliesThe event handlers in my parent class are never called though the events are raised in the child class.
The Code:
Public Class childForm
Public Event checkboxchangedEvent(ByVal checkbox1 As Boolean, ByVal checkbox2 As Boolean)
Private Sub checkboxchanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckBox1.CheckedChanged, CheckBox2.CheckedChanged
[code]....
Just had to remove remove statics and use Delegates refering to class. i have got a little problem in one of my project.I need help to resolve it.My application Connect several FTP server with the same Class.I'm using TCPclient for few specifics Commands.The problem : All threads call the same TCPclient wich can't connect several server at once.I would like to create a New TCPclient for each thread.
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I'm trying to remove individual nodes from their parent, I tried the Remove method but it doesn't seem to be working. How is this done? Is this a bug or what?
Sub Main()
Dim xml =
<?xml version="1.0" encoding="utf-8"?>
[Code].....
How can i remove an array item by selecting an item from listobx and press remove/delete button?for an example, if i want remove index 2 from listbox, so the array should remove index 2 item and move the item of index 3 to index 2 and so on.
View 7 RepliesI'm trying to get a ComboBox to remove the 6th string in the ComboBox or an index of (5) but it doesn't remove it here is the function I am using:
if ComboBox1.items.count = 6 then
ComboBox1.Items.RemoveAt(5)
End If
I don't understand why I only get 1 Message Box in the following case when I run using (CTRL-F5 - Run Without Debugger) in VS2010:
Public Class Form1
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
' Add the event handler for handling UI thread exceptions to the event.
AddHandler Application.ThreadException, AddressOf ThreadExceptionHandler
[code].....
Is it possible to determine using VB.NET whether a certain event has any handlers attached to it? I don't own the event, in this particular case I want to know which of the items in a Windows.Forms.MenuStrip have their ToolstripMenuItem.Click event handled.
View 1 RepliesHere is a problem with focus. I have a container(e.g. Panel) which contains some controls. How can I detect the focus event whenever any of the controls in the container has received or lost focus? Do I need to add handler for each control?
example: If all controls in the container have no focus, the container will report as inactive; if one of the controls has focus, the container will report as active.
I designing download manager in vb.net. Which supports various file premium hosts[rs,hotfile].... My need is how to get the download handler of IE. When user navigate the link in IE the download link wil be catch by professional application like(dap, idm).... How to achieve in my application? I meant how to get redirected link?
View 2 RepliesWhen adding a handler I want to be sure adding a unique(single) instance of the delegate. [code]...
View 18 RepliesHow I can run handler from one application to another, for example: In application one i have form1 and button. In application two I have also form1 and button. Now how I can run handler for button on form1 in first application from applicaton two?
View 2 RepliesI am trying to add a Handler, but it do not work. what am I missing? I getting this error.
Dim EditingTextBox As New TextBox
Dim Save_Button As New Button
Dim Cancel_Button As New Button
Private Sub Labels_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Label1.Click
[code]....
why the code...
Form1.Controls.Remove(myCustomControl) ...does not remove the control.
Because whenever I remove a control and add it again, it does not Load but rather just changes its visibility from false to true and all the variables are not reloaded.
I tried to use .Dispose() but VB.net tells me thatit can't access a disposed object whenever I try to add the control again.
I've been looking for a solution to this for several hours now and cannot find a solution.
The Scenario:I have a masterpage baseclass (called basemaster)All of my master pages inherit from basemaster
basemaster defines an event 'Public Event HandleClickEvent As EventHandler'I have a masterpage named master1
master1 defines an event handler 'Public Shadows Event HandleClickEvent As EventHandler'master1 has a user control named usr1 usr1 has a button that raises event ButtonClicked when clicked I have a page (thePage) that uses master1 thePage has a button click event handler that it registers like so: 'AddHandler Master.HandleClickEvent, AddressOf HandleTheClick' master1 has code something like:
Protected Sub Usr1_ButtonClicked(ByVal sender As Object, ByVal e As System.EventArgs) Handles Usr1.ButtonClicked RaiseEvent HandleClickEvent(sender, e) End Sub when thePage loads I see it register the handler on master1 when the button is clicked, Usr1_ButtonClicked is fired and I step through the RaiseEvent but HandleClickEvent on thePage is never reached.
Is it possible in VB.NET to easily write an event handler that will handle every event that fires? I'm wondering if one could make a logging system using something like this.I'm wanting to do something like (in pseudocode):
Public Sub eventHandledEvent(ByVal sender As Object, ByVal e As EventArgs)
File.Write(sender.EventName)
End Sub
I realize it would be slow, but it wouldn't be for a production system, only as a development tool.
I am trying to upload images using generic handler as shown below and I have a normal aspx page where I am showing all the uploaded images after uploading.Everything is working fine.
CODE:
Now I want to add a session variable by generating a random string and add the uploaded images to the newly created random string.
1.I have seen this Question on SO to use System.Web.SessionState.IRequiresSessionState for sessions and how do I create a folder with that and add my images to that folder after doing that how do I access this session variable in my normal aspx page.
2.(Or) the better way is create session variable in aspx page and pass that to handler?If so how can I do that?
3 .I am trying to find the control from my handler.Is that possible?If anyone knows how to get this then also my problem will get resolved so that I am trying to create a session from m aspx page.