event-handling

问题 I'm a newbie to WMI and I need to implement RegistryValueChangeEvent in a C# service. I need an event handler that gets triggered each time any one of a set of registry values is changed. I want behavior similar to the FileSystemWatcher class's Changed event, but for registry values. If there's some other technique I could use to accomplish the same task, I'd appreciate that as well. My minimum requirement is that it be a better solution than what I have now: polling every 20 seconds and

问题 I'm using the following code to detect when a dynamically generated button is clicked. $(document).on("click",".appDetails", function () { alert("test"); }); Normally, if you just did $('.appDetails').click() you could use $(this) to get the element that was clicked on. How would I accomplish this with the above code? For instance: $(document).on("click",".appDetails", function () { var clickedBtnID = ?????? alert('you clicked on button #' + clickedBtnID); }); 回答1: As simple as it can be Use

问题 I'm using the following code to detect when a dynamically generated button is clicked. $(document).on("click",".appDetails", function () { alert("test"); }); Normally, if you just did $('.appDetails').click() you could use $(this) to get the element that was clicked on. How would I accomplish this with the above code? For instance: $(document).on("click",".appDetails", function () { var clickedBtnID = ?????? alert('you clicked on button #' + clickedBtnID); }); 回答1: As simple as it can be Use

问题 Let's say I have some variable defined using the statement int someVariable; . While the code runs, the variable's value changes. How can I track the changes in this variable? How could I implement some Listener that behaves like onSomeVariableChangedListener? I also need to know when some other method in one page has been executed so I can set a Listener in another class. 回答1: This is one of the many reasons to hide variables behind setter/getter pairs. Then in the setter you can notify your

问题 This question already has answers here : How to ensure an event is only subscribed to once (5 answers) Closed 4 years ago . Duplicate of: How to ensure an event is only subscribed to once and Has an event handler already been added? I have a singleton that provides some service and my classes hook into some events on it, sometimes a class is hooking twice to the event and then gets called twice. I'm looking for a classical way to prevent this from happening. somehow I need to check if I've

问题 This question already has answers here : How to ensure an event is only subscribed to once (5 answers) Closed 4 years ago . Duplicate of: How to ensure an event is only subscribed to once and Has an event handler already been added? I have a singleton that provides some service and my classes hook into some events on it, sometimes a class is hooking twice to the event and then gets called twice. I'm looking for a classical way to prevent this from happening. somehow I need to check if I've

问题 This question already has answers here : Preserving a reference to “this” in JavaScript prototype functions [duplicate] (7 answers) Closed 3 years ago . What is the correct way to preserve a this javascript reference in an event handler stored inside the object's prototype? I'd like to stay away from creating temp vars like '_this' or 'that' and I can't use a framework like jQuery. I saw a lot of people talk about using a 'bind' function but was unsure of how to implement it in my given

问题 I have a third-party editor that basically comprises a textbox and a button (the DevExpress ButtonEdit control). I want to make a particular keystroke ( Alt + Down ) emulate clicking the button. In order to avoid writing this over and over, I want to make a generic KeyUp event handler that will raise the ButtonClick event. Unfortunately, there doesn't seem to be a method in the control that raises the ButtonClick event, so... How do I raise the event from an external function via reflection?

问题 What do sender and eventArgs mean/refer to? How can I make use of them (for the scenario below)? Scenario: I'm trying to build a custom control with a delete function, and I want to be able to delete the control that was clicked on a page that contains many of the same custom control. 回答1: The sender is the control that the action is for (say OnClick, it's the button). The EventArgs are arguments that the implementor of this event may find useful. With OnClick it contains nothing good, but in

问题 How is this done? 回答1: This is a good question, and I actually don't think it can be done easily. (Some discussion on this) If it is super duper important for you to have this functionality, you could hack it like so: function singleClick(e) { // do something, "this" will be the DOM element } function doubleClick(e) { // do something, "this" will be the DOM element } $(selector).click(function(e) { var that = this; setTimeout(function() { var dblclick = parseInt($(that).data('double'), 10);