event-handling

问题 I am making a WinForms application which includes a form that uses a DataGridView to handle simple data manipulation. To ensure accurate entry while mitigating clutter (read: without using DataGridViewComboBoxColumn ) I have a couple event handlers which temporarily turn a DataGridViewTextBoxCell into an equivalent DataGridViewComboBoxCell connected to values known to be "clean" when editing events are raised (typically when an editable cell is clicked): private void OnCellEndEdit(object

问题 I'm making a very simple application where you can click on square divs to change their color from white to black. However, I'm having trouble. I'd like to use the onClick function to allow a user to click on a square to change its color, but it doesn't seem to be working. I've tried using spans and empty p tags, but that doesn't work either. Here is the code in question: var Box = React.createClass({ getInitialState: function() { return { color: 'white' }; }, changeColor: function() { var

问题 I'm making a very simple application where you can click on square divs to change their color from white to black. However, I'm having trouble. I'd like to use the onClick function to allow a user to click on a square to change its color, but it doesn't seem to be working. I've tried using spans and empty p tags, but that doesn't work either. Here is the code in question: var Box = React.createClass({ getInitialState: function() { return { color: 'white' }; }, changeColor: function() { var

问题 The two key event argument classes KeyEventArgs and PreviewKeyDownEventArgs each have two properties, KeyCode and KeyData , which are both of the enumeration type Keys. What is the difference between these two properties? Do the values in them ever differ from each other? If so, when and why? 回答1: KeyCode is an enumeration that represents all the possible keys on the keyboard. KeyData is the KeyCode combined with the modifiers (Ctrl, Alt and/or Shift). Use KeyCode when you don't care about

问题 I'm creating a client-side dynamic blog engine. Now I need a event system to handle many actions from DOM elements and the engine. Such as the engine is loading a article,user is switching a theme... And I don't want to use a library to do this. So far I've done is using a list to store callbacks for a event . But I want each callback works with different objects.Like the DOM event. I may add an id-like property to each object, and store (id,callbacks) in a event.I feel it's not so good.When

问题 Got a quick question which I hope someone can answer. Basically I have a String variable which needs changing based upon the value in a combo box which has an event listener attached to it. However if I make the string final then it cant be changed, but if i don't make it final then eclipse moans that it isn't final. Whats the best (and simplest) work around? Code is as follows final String dialogOutCome = ""; //create a listener for the combo box Listener selection = new Listener() { public

问题 Got a quick question which I hope someone can answer. Basically I have a String variable which needs changing based upon the value in a combo box which has an event listener attached to it. However if I make the string final then it cant be changed, but if i don't make it final then eclipse moans that it isn't final. Whats the best (and simplest) work around? Code is as follows final String dialogOutCome = ""; //create a listener for the combo box Listener selection = new Listener() { public

问题 I want to add tooltips on a Leaflet map (without markers) and make them clickable. The following code adds a tooltip but it's not clickable: var tooltip = L.tooltip({ direction: 'center', permanent: true, interactive: true, noWrap: true, opacity: 0.9 }); tooltip.setContent( "Example" ); tooltip.setLatLng(new L.LatLng(someLat, someLon)); tooltip.addTo(myLayer); tooltip.on('click', function(event) { console.log("Click!"); }); How can I make it work? 回答1: To receive clicks on a L.Tooltip object,

问题 I want to add tooltips on a Leaflet map (without markers) and make them clickable. The following code adds a tooltip but it's not clickable: var tooltip = L.tooltip({ direction: 'center', permanent: true, interactive: true, noWrap: true, opacity: 0.9 }); tooltip.setContent( "Example" ); tooltip.setLatLng(new L.LatLng(someLat, someLon)); tooltip.addTo(myLayer); tooltip.on('click', function(event) { console.log("Click!"); }); How can I make it work? 回答1: To receive clicks on a L.Tooltip object,

问题 I've always assigned event handlers like this, guided by Intellisense auto-completion. RangeSelector.RangeChanged += new EventHandler(RangeSelector_RangeChanged); I've recently noticed one of my colleagues does it this way. RangeSelector.RangeChanged += RangeSelector_RangeChanged; Both methods are syntactically correct, compile and behave as expected. What are the differences, benefits or disadvantages of these methods. Do they result in the same IL code or is there some subtle difference