event-handling

问题 The other day I was trying to code a small C++ programming using the SDL multimedia library, and I ran into this small snag which I eventually solved through trial and error. The issue is, I understand what I did to solve the problem, but I don't really understand the nature of the problem! The issue was with keyboard event handling in SDL. The code to handle a single key press to exit the program is straight forward and simple. [eventQueue is an SDL_Event structure] //checks for keypress

问题 I am learning Qt framework (C++) and was wondering if QT has any mechanisms to protect slots from being called before an object is fully initialized. Consider Class A constructor: A::A() { mTreeView = new QTreeView(); ... connect(mTreeView, &QTreeView::customContextMenuRequested, this, &A::OnContextMenuRequested); ... } My worry is the user would be able to right-click on the tree-view before A's constructor has finished. Another context is as follows: A::A() { mQObj = new MyQObject();

问题 I was reading jQuery's page for animate() http://api.jquery.com/animate/ Its examples don't mention about if using <a href="#" id="clickme">click me</a> ... $('#clickme').click(function() { $('#someDiv').animate({left: "+=60"}); }) we actually still have to return false like in the old days? $('#clickme').click(function() { $('#someDiv').animate({left: "+=60"}); return false; }) (but then, those examples didn't use a <a> for the "click me"... but used something else. Otherwise the page will

问题 How to use KeyBindings in JFX 2? I need to reassign Enter key from carrige returning to my own function, and for carrige returning assign CTRL+ENTER I've tried this way, but still it makes a new line. messageArea.addEventFilter(KeyEvent.KEY_PRESSED, new EventHandler<KeyEvent>() { @Override public void handle(KeyEvent keyEvent) { if (keyEvent.getCode() == KeyCode.ENTER) { sendMessage(); } } }); 回答1: If want to prevent the default behavior of event you are filtering, you need to consume it.

问题 I started coding something complicated and then realized my event handlers don't work, so I super simplified a button with an event handler. Please see the code below and maybe you can tell me why it doesn't fire? using System; using System.Collections.Generic; using System.Runtime.InteropServices; using System.Web.UI; using System.Web.UI.WebControls.WebParts; using Microsoft.SharePoint; using System.Web.UI.WebControls; namespace PrinterSolution { [Guid("60e54fde-01bd-482e-9e3b-85e0e73ae33d")

问题 I try to execute a function on an audio play event : jQuery('audio').on('play', function () { /* ... */ }); But my element is not present at the time this function is executed, so it's not selected. Instead I have the habit to use a different syntax when I need to trigger event for dynamic added content : jQuery('.constant-container').on('play', 'audio', function () { /* ... */ }); Where the .constant-container does not change. But this solution does not seems to work, the audio element does

问题 Here's the problem: This is for a WPF app that uses C# and LINQ to SQL. When a user wants to look at a list of customers, he/she begins entering the name in a textbox. The textchanged event uses the input text to define the where clause of a LINQ statement that filters the list. I currently have two such text boxes that run essentially the same code, but I cannot reduce that code to a single function - I'll be using customer lists in a bunch more places. Here's a bit of the code: private void

问题 I some add textfields programmatically into a TableView when the rows are created. I am trying to subscribe to the TouchUpInside event of these textFields by doing this UITextField *eTextField = [[UITextField alloc] initWithFrame:CGRectMake(110, 12, 145, 25)]; eTextField.delegate = self; [eTextField addTarget:self action:@selector(showPicker) forControlEvents:UIControlEventTouchUpInside]; showPicker is an IBAction with no parameters.It never gets fired. Is there something I else I need to do?

问题 Is it possible to use interface method as event handlers in Delphi 2007? The simple versions don't work: type TMyEvent = procedure of object; IMyInterface = interface procedure Handler; end; TMyClass = class(TInterfacedObject, IMyInterface) public procedure Handler; end; var ev: TMyEvent; obj: TMyClass; intf: IMyInterface; begin obj := TMyClass.Create; intf := obj; ev := obj.Handler; // compiles ev := intf.Handler; // <== Error E2010 (incompatible types) end. Adding @ or Addr changes the

问题 Please have a look at the code below. function deferredClick(f) { return (function (e) { var $this = $(e.currentTarget); console.log('Actual target: ', e.currentTarget); window.setTimeout(function () { console.log('Target I get here: ', e.currentTarget); f.call($this.get(0), e); }, 1000); }); } function clickResponder(e) { var $this = $(e.currentTarget); $("#out").html('Clicked - ' + $this.val()); } $('input[type="button"]').on('vclick', deferredClick(clickResponder)); The idea is to trigger