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 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
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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:
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I 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 have nine pictures that I need to animate -I need to use the ToString method and a counter to concatenate a file name into a string variable from the Image.FromFile method. Once the counter reaches its maximum value, and the last picture is displayed, the counter should be reset to zero or one depending on how the first image file has been name. Also a static counter variable should be incremented in the time routine. what I have so far -- I know what I have to do; however, I just do not know how to code this properly.. Right now I have this going thru a button procedure but it needs to go through a timer.
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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 RepliesWhen you click on a button control on a web form visual studio automatically put in this code for you in the code behind.
Protected Sub btnSave_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnFlightInfo.Click
end Sub
Say for example, I wanted to call this method from another method. How would I do that? I know that the sender is the actual button object, but what is e? Here is what I have so far inside another sub. Just trying to get a better understanding of how this method works.
btnSave_Click(btnSave, ??what would you put there??)
Suppose I have the following construct:
Public Sub SomeMethod()
Try
doSomething()
Catch ex as Exception
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And I would like to write handleException(ex). Suppose my class has different options of handling events:
Public Enum ExceptionHandlingType
DisplayInMessageBox 'Display in msgbox
ThrowToCaller 'Raise the error to the caller routine
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Below is my attempt at writing "handleException". It seems no matter what I do, if the object was set with Exception mode of "ThrowToCaller" then the stack trace gets all messed up when I use handleException(). How can I just have a clean stack trace generated when the option is "ThrowToCaller" (every other option seems like it is working fine)
Public Sub handleException(ex as Exception)
Select Case mExceptionHandling
Case ExceptionHandlingType.DisplayInMessageBox
MsgBox(ex.Message)
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With reference to my previous thread on Paint event handler.. [URL] I went to read up more on Paint Event Handler.. I have a button which draw out a path based on the user selection.. Below contains the drawing of the path portion of the button click event code
[Code]...
However It did not activate the paint event when I clicked on the button.. Instead, the paint event still activate even before I click on the button? So can anyone teach me on how to activate the paint event when I click on a button?
remove 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 planning to use a shared variable to implement a logging facility. Have a look at the code below:
Imports System.IO
Public Class TestClass
Public Shared objError As New StreamWriter("C:Test.txt")
End Class
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I think I have found my answer here: [URL] "A static variable continues to exist and retains its most recent value. The next time your code calls the procedure, the variable is not reinitialized, and it still holds the latest value that you assigned to it. A static variable continues to exist for the lifetime of the class or module that it is defined in."
I am not convinced that this is the best way to create a logging facility.
I have a form in VB.NET that is used as a dialog in a mainform. Its instances are always locally defined, there's no field for it. When the user clicks the OK button in the dialog, it will fire an event with exactly one argument, an instance of one of my classes. Since it is always a local variable, how can I add an event handler for that event?
Code for the event, a field in MyDialog:
public Event ObjectCreated(ByRef newMyObject as MyObject)
Code for the main form to call dialog : (never mind the syntax)
Dim dialog As New MyDialog()
dialog.ShowDialog(Me)
AddHandler ObjectCreated, (what do I put here?) //Or how do I add a handler?
Im making a site in Visual Studio using vb and I have a variable in page_load but need its value in the event handler of a button for passing on session.
View 5 RepliesOn one side, in Vb.Net when you add an event handler to an object the created method is named: <NameOfTheObject>_<NameOfTheMethod>.As I like to have consistent syntax I always follow this rule when creating event handlers by hand.On the other side when I create private variables I prefix them with m_ as this is a common thing used by the community, in C# people use to put _ at the beginning of a variable but this is no CLS compliant.
View 1 RepliesI 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
[CODE]
What's the best way to dynamically remove method calls at runtime? Essentially what I'd like to do is pass a parameter to my application. Let's call the parameter level. Depending on the value of level, I'd like to essentially remove all the calls that have higher levels. I have the following but was wondering if there were a simpler/cleaner way to remove the calls:
Ideally I'd really like to write something like:
Log5("message")
And just have Log5 work or not call if it doesn't exist. My goal is to actually remove the call. The overhead for calling level 5 logs that test and return is fairly high and I rarely use it.
Module Module1
Delegate Sub Log(ByVal message As String)
Public Log1 As Log = Nothing
Public Log2 As Log = Nothing
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I have a toolstriptextbox and a custom context menu strip with a "Cut" menu item. When you select text in the textbox, display the context menu and select the menu item, the cut method of the textbox is being executed, the text is pushed to the clipboard, but the text is not being removed from the textbox. The code is as simple as follows.
Sub menuItemCut_Click (byval sender as object, e as eventargs) handles menuItemCut.Click
textbox.Cut()
End Sub
I have verified the event is fired, and the selected text in textbox gets sent to the clipboard. For some reason the selected text is not removed from the textbox. Has anyone ran into this issue before when working with a toolstriptextbox?
Error1Option Strict On does not allow narrowing in implicit type conversions between method 'Private Sub searchResult_SearchFileMatches(sender As Object, e As Jam.Shell.FileMatchEventArgs)' and delegate 'Delegate Sub EventHandler(sender As Object, e As System.EventArgs)'. on RED Text
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Ive been reading up on the split function on Msdn but grasp how if I had a text in textbox1 it would remove all spaces and textbox1.text and is split the easiest method?
View 3 RepliesAny method to remove the Filled Rectangle I put on a form / control using FillRectangle method? Or do I have to over-paint it with the same colour as the form ?
View 1 RepliesI am trying to execute a command that works with hard coded variables, but when I try and replace the name test below with selectedname, I cannot get the syntax for escaping the command. The basic idea is I am using WMI to query the app pool names and then selecting one and storing in the slectedname variable, which works when I test with a msgbox(selectedname) line. It also shows up when I am stepping through, but does not get passed to the bottom command. The function where I am trying to execute the command is
Private Sub Stpbtn_Click(sender As Object, e As System.EventArgs) Handles Stpbtn.Click
Dim selectedname As String
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If I have a string that contains the name of a control is there a way to call that control's click event?
Dim a as string = "MyButton1"
Now I want to call MyButton1.Click Method or MyButton_Click Event using the contents of a.
regarding this error: 'sqlquery' is a variable but is used like a method.Near the bold code is it gives the above error.
string[] sqlQuery = new
string[10];
for (int i = 0; i <= sqlQuery.Length - 1; i++)
{
char[] splitterequal = {
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I am working in VB.NET Win forms and what I would like to do is create an object to use its properties.
The trick is that I want to create a reference to an existing class using a string variable that gets passed in to my method.