in the following:
this.ExitButton .Click += new System.EventHan dler(this.ExitB utton_Click);
if I saw an equation, such as y +=x;
then y = y+x.
But what is the meaning in the event handler. I realize it is adding an
event handler for the click event of the exit button, but how do i reason
through the 2 step process inferred by the += equation.
Beth 3 1971
"Beth" <sc***********@ msn.com> wrote in message
news:OQ******** *****@tk2msftng p13.phx.gbl... in the following: this.ExitButton .Click += new System.EventHan dler(this.ExitB utton_Click);
if I saw an equation, such as y +=x; then y = y+x.
But what is the meaning in the event handler. I realize it is adding an event handler for the click event of the exit button, but how do i reason through the 2 step process inferred by the += equation.
+= with events means add an event handler to the set. It is basically a
specialization of hte += operator to hook up event handlers, unlike the
equation y = y+x, += just specifcally means "hook up this handler to the
event." It calls the add handler for the event. There isn't a Click = Click
+ Handler because it isn't possible to assign to an event from outside of
the class.
If I understand waht you are asking, anyway.
It goes a little bit beyond that, and has it's roots in how delegates
are handled.
When you attach a delegate to an event handler, the delegate at the end
of the list ends up being assigned the reference to the delegate that is
being attached. Your invocation list is actually a linked list.
So, when you use += to attach a delegate to an event handler, it kind of
makes sense when you expand it now to event = event + new delegate, because
what is happening is that you are taking the invocation list, and adding the
event handler to the end of the invocation list.
Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard. caspershouse.co m
"Daniel O'Connell [C# MVP]" <onyxkirx@--NOSPAM--comcast.net> wrote in
message news:ub******** ********@TK2MSF TNGP12.phx.gbl. .. "Beth" <sc***********@ msn.com> wrote in message news:OQ******** *****@tk2msftng p13.phx.gbl... in the following: this.ExitButton .Click += new System.EventHan dler(this.ExitB utton_Click);
if I saw an equation, such as y +=x; then y = y+x.
But what is the meaning in the event handler. I realize it is adding an event handler for the click event of the exit button, but how do i reason through the 2 step process inferred by the += equation.
+= with events means add an event handler to the set. It is basically a specialization of hte += operator to hook up event handlers, unlike the equation y = y+x, += just specifcally means "hook up this handler to the event." It calls the add handler for the event. There isn't a Click = Click + Handler because it isn't possible to assign to an event from outside of the class.
If I understand waht you are asking, anyway.
Thank you, that makes sense.
"Nicholas Paldino [.NET/C# MVP]" <mv*@spam.guard .caspershouse.c om> wrote in
message news:e1******** ******@TK2MSFTN GP12.phx.gbl... It goes a little bit beyond that, and has it's roots in how delegates are handled.
When you attach a delegate to an event handler, the delegate at the end of the list ends up being assigned the reference to the delegate that is being attached. Your invocation list is actually a linked list.
So, when you use += to attach a delegate to an event handler, it kind of makes sense when you expand it now to event = event + new delegate, because what is happening is that you are taking the invocation list, and adding the event handler to the end of the invocation list.
Hope this helps.
-- - Nicholas Paldino [.NET/C# MVP] - mv*@spam.guard. caspershouse.co m
"Daniel O'Connell [C# MVP]" <onyxkirx@--NOSPAM--comcast.net> wrote in message news:ub******** ********@TK2MSF TNGP12.phx.gbl. .. "Beth" <sc***********@ msn.com> wrote in message news:OQ******** *****@tk2msftng p13.phx.gbl... in the following: this.ExitButton .Click += new System.EventHan dler(this.ExitB utton_Click);
if I saw an equation, such as y +=x; then y = y+x.
But what is the meaning in the event handler. I realize it is adding an event handler for the click event of the exit button, but how do i reason through the 2 step process inferred by the += equation.
+= with events means add an event handler to the set. It is basically a specialization of hte += operator to hook up event handlers, unlike the equation y = y+x, += just specifcally means "hook up this handler to the event." It calls the add handler for the event. There isn't a Click = Click + Handler because it isn't possible to assign to an event from outside of the class.
If I understand waht you are asking, anyway.
This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
by: cjl |
last post by:
Hey all:
I'm trying to write a cross-browser (IE and firefox) event handler for
the mousewheel. Basically my web app is an image viewer, so if you
scroll "down" with the wheel the next image should be displayed and if
you scroll "up" the previous image should be displayed.
So far I have:
function handleMouseWheel(e)
|
by: Anil |
last post by:
iam getting too many messages boxes when i include a message box in a KeyUP eventhanler function which in turn have validation if functio
my code i
when i press the ok button of the message box , message box pops again how to avoid it
private void txtJobName_KeyUp(object sender, System.Windows.Forms.KeyEventArgs e
if(e.KeyValue == 1
MessageBox.Show("xyz")
txtJobName.Focus()
|
by: Siobhan |
last post by:
H
In VB6 you run the event handler code from anywher
e.g
Call Button1_Click ran the code behind your button1 click even
Can you do this in VB.Net and if so how
Our system uses shortcut keys for saving, e.g. End and because focus does not leave the control the Validating event does not fire so I would like to be able to run the validating event for the aactive control when End is pressed on the form and then stop the save if the validation...
|
by: Larry Lard |
last post by:
Experiment A:
Start a new Windows Forms project. Double click Form1. This is what is
generated:
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
End Sub
Experiment B:
|
by: =?Utf-8?B?bXIgcGVhbnV0?= |
last post by:
In the Visual Studio VB user interface when I want to create an event handler
for a control, I go to the code view for the form and in a combo box at the
top left I pick the control. All the events for the control are in another
combo box on the right. When I click the event, my handler is set up.
In C# this does not appear to be the case. I have been going to the form
designer, finding my way to the control's section, and adding...
| |
by: gouqizi.lvcha |
last post by:
Does VS2005 has the ability to generate event handler code in the code
behind? For example, I cannot find the UI to help me to create event
like Page_Init().
Tom
|
by: cradius |
last post by:
I've got a custom user control, with a DataList, that is dynamically added to the page. In the DataList is an ImageButton that, when clicked, fires off the ItemCommand event of the DataList and passes the CommandName and CommandArgument of the ImageButton to the event handler. The event handler then passes data to another user control (cart) on the same page and displays some data. This all works great except for the very first time one of the...
|
by: =?Utf-8?B?U3dhcHB5?= |
last post by:
Can anyone suggest me to pass more parameters other than two parameter for
events like the following?
Event:
Onbutton_click(object sender, EventArgs e)"
Event handler:
button.Click += new EventHandler(Onbutton_click);
I want to pass more information related that event. & want to use that
|
by: Cyclestump |
last post by:
We're using .NET 2.0, VB. I expect a .Click event handler to be called, but it's not.
When I click on the webpage link named btnSearch, the confirmSearchOK() javascipt function is called(I see this when I uncomment the alert() ), which contains the __doPostBack() call. On the .VB side, the handler never gets called. BTW, the handler was created by double-clicking on the .ASPX object in the 'Design' mode.
Any help would be appreciated....
|
by: marktang |
last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look !
Part I. Meaning of...
|
by: Oralloy |
last post by:
Hello folks,
I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>".
The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed.
This is as boiled down as I can make it.
Here is my compilation command:
g++-12 -std=c++20 -Wnarrowing bit_field.cpp
Here is the code in...
| |
by: jinu1996 |
last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth.
The Art of Business Website Design
Your website is...
|
by: agi2029 |
last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own....
Now, this would greatly impact the work of software developers. The idea...
|
by: conductexam |
last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one.
At the time of converting from word file to html my equations which are in the word document file was convert into image.
Globals.ThisAddIn.Application.ActiveDocument.Select();...
|
by: TSSRALBI |
last post by:
Hello
I'm a network technician in training and I need your help.
I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs.
The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols.
I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
|
by: adsilva |
last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
|
by: muto222 |
last post by:
How can i add a mobile payment intergratation into php mysql website.
| |
by: bsmnconsultancy |
last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...
| |