event-handling

问题 So, I create a TreeViewItem (parentNode), and I add TreeViewItems into the parentNode TreeViewItem. I then add a MouseButtonEventHandler to the parentNode, and now all the TreeViewItems inside parentNode have the MouseButtonEventHandler. I've run the debugger to see if I have code that was accidentally written to add the MouseButtonHandler, but there isn't... Edit: I did additional tests, and it even goes two levels down. Is there a way to isolate eventhandlers to only the specific node and

问题 http://msdn.microsoft.com/en-us/library/ee2k0a7d.aspx Event handling is also supported for native C++ classes (C++ classes that do not implement COM objects), however, that support is deprecated and will be removed in a future release . Anyone knows why? Couldn't find any explanation for this statement. 回答1: It's totally non-standard kludge that probably has very little actual users. And I mean non-stndard kludge even in WinNT and Microsoft-private world. COM has much richer repertoire for

问题 I am trying to add click event listener to my divs that I am creating in my JS dynamically. My Javascript snippet of function that is called each time to create the Div: var listDiv = document.createElement("div"); listDiv.className = "list"; listDiv.addEventListener = ('click',gotoOutcomesLO, false); The Function that is called by the click event: function gotoOutcomesLO(e){ if(typeof(Storage)!=="undefined"){ var ele = e.target; var text = ele.getAttribute("name"); sessionStorage.test = text

问题 Can someone clarify the my understanding of variable scope within event handlers? Take a look at the code below: var address = new Array(); address[0] = '1 Smith Street'; address[1] = '2 Smith Street'; for(var rownum=0; rownum<=address.length; rownum++) { if(address[rownum]) geocoder.geocode( {'address': address[rownum]}, geocodeCallBack); } function geocodeCallBack(results, status) { var marker = new google.maps.Marker({ map: map, position: results[0].geometry.location, title: results[0]

问题 I have to return query result from indexedDB, but the result is only available in onsuccess event handler. 1 function listPeople(){ ... 4 var open = indexedDB.open("AccordionDatabase",1), 5 res; 6 7 open.onsuccess = function(){ 8 var db = open.result; 9 var transaction = db.transaction("PeopleStore", "readwrite"); 10 var store = transaction.objectStore("PeopleStore"); 11 var request = store.getAll(); 12 request.onsuccess = function(event){ 13 res = event.target.result; 14 console.log(res); 15

问题 I have an event handler that I would like to have executed after the default javascript handling of that event occurs. Is this possible? EDIT: For example: everytime a keypress event is fired, i'm logging event information about that keypress(similar to console.log). Now, when I press backspace and view the fields contents via the event handler, the value of the text field produces the value without the backspace since the event handler grabs the contents of the field before the actual

问题 I have a QMainWindow with an event filter installed. After I open and close a QDialog the keyboard arrow keys don't respond since QMainWindow receives only ShortcutOverride events instead of KeyPress events. When I changed the QMainWindow's event filter to handle ShortcutOverride events I got a strange behavior since in my program each key press event is preceded by two shortcut override events (why??). This doesn't work - events are handled more than once: bool eventFilter(QObject *, QEvent

问题 I have a WPF TextBox, defined like this: <TextBox Text="{Binding Path=/Comments}" Margin="351,193.91,10,36" x:Name="txtComments" IsReadOnly="True" VerticalScrollBarVisibility="Auto" LostFocus="txtComments_LostFocus" MouseDoubleClick="txtComments_MouseDoubleClick" AcceptsReturn="True" /> This works exactly as I would like; however, when the VerticalScrollBars are visible, if you rapidly click the ScrollBar the txtComments_MouseDoubleClick event is fired. Is there any way I can change this

问题 After renaming my function the code stopped working. That new name scrollIntoView seems to be clashing with the element.scrollIntoView() method. <div onmousedown="scrollIntoView('id001')"/> function scrollIntoView(id) { alert(id); } I've created a simple test case https://jsfiddle.net/mgtn215y/ which has shown my function is simply ignored in favor of element.scrollIntoView() even it is not called on element attributes do not match The solution is obvious - to use a different function name.

问题 According to John Resig's 'Learning Advanced JavaScript' (http://ejohn.org/apps/learn/#83) it's incorrect to bind an object's method to event handler without passing the original object as context, however I find the example flawed. It claims the clicked property gets set accidentally. Here's a counter-example. var Button = { click: function(){ this.clicked = true; console.log( elem.clicked ); } }; var elem = document.createElement("li"); elem.innerHTML = "Click me!"; elem.onclick = Button