event-handling

问题 I am very curious why do we have to use java.awt.EventQueue.invokeLater to control swing components. Why can't we do that in normal thread? What exactly is going on behind the scenes? From what I have noticed if I have a JFrame I can set visibility to true or false from the main thread without getting any errors, and it does seem to work. So what exactly do I achieve by using java.awt.EventQueue.invokeLater ? I am also fully aware that I can use SwingUtilities.invokeLater but as explained

问题 I have a custom usercontrol and I want to do something relatively simple. When ever a numeric up down in that usercontrol's value changes, have the main form update a display window. This is not a problem if the NUD was not in a usercontrol but I can't seem to figure out how to have the event handled by the mainform and not the usercontrol. 回答1: You need to create an event handler for the user control that is raised when an event from within the user control is fired. This will allow you to

问题 This question already has answers here : Is right click a Javascript event? (17 answers) Closed 6 years ago . I want to block the standard context menus, and handle the right-click event manually. How is this done? 回答1: Use the oncontextmenu event. Here's an example: <div oncontextmenu="javascript:alert('success!');return false;"> Lorem Ipsum </div> And using event listeners: el.addEventListener('contextmenu', function(ev) { ev.preventDefault(); alert('success!'); return false; }, false); Don

问题 This question already has answers here : Is right click a Javascript event? (17 answers) Closed 6 years ago . I want to block the standard context menus, and handle the right-click event manually. How is this done? 回答1: Use the oncontextmenu event. Here's an example: <div oncontextmenu="javascript:alert('success!');return false;"> Lorem Ipsum </div> And using event listeners: el.addEventListener('contextmenu', function(ev) { ev.preventDefault(); alert('success!'); return false; }, false); Don

问题 This question already has answers here : Closed 10 years ago . Possible Duplicates: Unsubscribe anonymous method in C# How do I Unregister ‘anonymous’ event handler I recently discovered that I can use lambdas to create simple event handlers. I could for example subscribe to a click event like this: button.Click += (s, e) => MessageBox.Show("Woho"); But how would you unsubscribe it? 回答1: The C# specification explicitly states (IIRC) that if you have two anonymous functions (anonymous methods

问题 $(document).ready(function() { //set initial state. $('#textbox1').val($(this).is(':checked')); $('#checkbox1').change(function() { $('#textbox1').val($(this).is(':checked')); }); $('#checkbox1').click(function() { if (!$(this).is(':checked')) { return confirm("Are you sure?"); } }); }); <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> <input type="checkbox" id="checkbox1"/><br /> <input type="text" id="textbox1"/> Here .change() updates the textbox

问题 If I want a function to be executed, I prefer doing inline js: <p id="element" onclick="doSomething();">Click me</p> because it is easier to debug. However, I hear people saying not to use inline js, and do: document.getElementById('element').onclick = doSomething; Why is the js event listener recommended? 回答1: Basically it has to do with the whole keep everything separate I believe. So keep HTML/CSS/JS all separate. It makes your HTML tidier and, I think, easier to navigate without. Then

问题 If I want a function to be executed, I prefer doing inline js: <p id="element" onclick="doSomething();">Click me</p> because it is easier to debug. However, I hear people saying not to use inline js, and do: document.getElementById('element').onclick = doSomething; Why is the js event listener recommended? 回答1: Basically it has to do with the whole keep everything separate I believe. So keep HTML/CSS/JS all separate. It makes your HTML tidier and, I think, easier to navigate without. Then

问题 I have the following code where I am handling an event twice. However I always want to ensure that mynewclass always handles the event first and then the local event handler code fires. I understand the MyClass event should fire first as that is the one created first but because the thread and enqueuing is taking place, I think its taking too long and its doing something in myhandleeventlocal before I want it to do that. Any way I can wait for it to happen? public MyMainClass { private

问题 I can't get $event working. Example: import 'package:angular2/core.dart'; @Component( selector: 'my-app', template: ''' <h1>{{title}}</h1> <button (click)="onTest($event)">testing</button> ''') class AppComponent { String title = 'Testing event'; onTest(event) { print(event); } } When I let pub serve the app, I throws a build error: Build error: Transform DirectiveProcessor on file_transfer|lib/app_component.dart threw error: Angular 2 could not understand the value in View#template. ''' <h1>