event-handling

问题 I want to test an event handler in React using Jest/Jasmine/Enzyme. MyComponent.js : import React from 'react'; class MyComponent extends React.Component { constructor(props) { super(props); this.clickHandler = this.clickHandler.bind(this); this.otherMethod = this.otherMethod .bind(this); } clickHandler() { this.otherMethod(); } otherMethod() {} render() { return <div onClick={this.clickHandler}/>; } } export default MyComponent; MyComponent.test.js : import React from 'react'; import {mount}

问题 Suppose there is a div which contains a link ( a href) and there are three event listeners - on-click- 1) for the entire page, 2) on div 3) a tag. If the user clicks on the a tag, how are the listeners triggered? What is the order of them being registered? 回答1: Essentially, it depends. There are 2 phases for events, Capturing (happens first), which goes document down, and Bubbling which goes element up. JS can do both, which is why when creating a custom Event listened you have the third

问题 I'm using Qt 4.3.1 (I'm not able to uptade at the moment) for a program, anyway in Windows dead keys (^, ´, `, ...) don't arrive at the keyPressedEvent(), i always have to press them twice. So why don't those dead keys arrive? How can I fix it? In MacOS everything works fine though. Thx, eL. 回答1: After looking at the Qt documentation I'm not sure if keyPressEvent is supposed to deliver dead keys or not. I'm actually kind of surprised that you see them on a Mac. I'm guessing that Qt is

问题 I am struggling with custom Gird view. Not exactly with Custom Gird view but its click event of child view. Major two query : first : issues is if i add simple image view and text view in grid and click on any of the item its working and shows me position of that item.but button when i add two button in grid replacing text view that will not call simple click event of item. second : i want to get click event for all three view like image and two button. if i click on image it should be do

问题 I am trying to make a program that asks the user to draw a shape and how many of that shape to draw in Python turtle. I dont know how to make the dialogue box so the user can say how many to add and make it run correctly. Any help will be awesome! Here is my code so far: import turtle steps = {"triangle": 3, "square": 4, "pentagon": 5, "hexagon": 6, "octagon": 7} #this is the dialogue box for what shape to draw and moving it over a bit so the #next shape can be seen def onkey_shape(): shape =

问题 In Silverlight 4, I wish to invoke one of the mouse button click events when the right mouse button is clicked. I have the RightMouseButtonDown click event wired up, but I don't know how to manually fire the MouseLeftButtonUp event. I have tried raising the event in the following fashion. private void MainLayoutRootMouseButton(object sender, MouseButtonEventArgs e) { MouseLeftButtonDown(sender, e); } However, a compiler error occurs: "The event 'System.Windows.UIElement.MouseLeftButtonDown'

问题 I am working on a fullscreen Ad, served through a publisher site that I do not have direct access to. The Ad utilises the tilt information from the iPad to change colours on the Ad. Everything works well standalone as it's own web page, but when served through our Ad engine, the html appears as a child window Object, and the 'deviceorientation' does not update in the Ad. I'm quite surprised by this, because the tilt info does get through to the Ad, but when I try to find the parent window

问题 i am using textchanged event and i disable it where i don't need as following object.Event -= new System.EventHandler(myHandler); //my code which doesn't need event handler object.Event += new System.EventHandler(myHandler); i used many times like this. but i needed sometimes 2 disable code like this: object.Event -= new System.EventHandler(myHandler); object.Event -= new System.EventHandler(myHandler); of course i finished it with 2 enable code object.Event += new System.EventHandler

问题 I have this error: Error 1 'johny.Form1' does not contain a definition for 'Form1_Load' and no extension method 'Form1_Load' accepting a first argument of type 'johny.Form1' could be found (are you missing a using directive or an assembly reference?) This is my code from the form's designer: // // Form1 // this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F); this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font; this.ClientSize = new System.Drawing.Size(456, 411); this

问题 I am currently working on winform that has a panel on it. I need to be able to use the up, down, left and right arrows on the panel and get something to happen. I tried adding the event with this line of code: (MainPanel as Control).KeyDown += new KeyEventHandler(panelKeyPressEventHandler); With this KeyDown code: public void panelKeyPressEventHandler(object sender, System.Windows.Forms.KeyEventArgs e) { MessageBox.Show("Here I am!"); switch (e.KeyCode) { case Keys.L: { break; } case Keys.R: