I have a ListView where each item has a checkbox. Initially there are no events attached and I set the state of the checkboxes programatically. After this I attach an ItemCheckedEventHandler and the event handler fires for each of the events that occurred before the handler was attached. Is there a way that I can clear the event queue before attaching the handler?
I was able to re-create when the event was added in the form constructor/InitializeComponent method.
And I was able to get around the problem by adding the event in the form's load event instead of the constructor/InitializeComponent method.
It's hacky, and I don't like it, but Application.DoEvents() might work for you.
Related
I'm trying to add a generic MouseClick event handler for every Control in my C# Winforms Application with a recursive method, but when I get the ToolStripBar the ToolStripItems are not in the Controls list and so they are not intercepted.
Do I have to do a test like this one?
"if the Control is a ToolStripBar then for every Items ToolStripItem attach the event handler"
Is there not a more general way?
thanks a lot
I keep seeing different variation of the code which is supposed to register an Inspector window close event but I have no idea where to put the code. Should it be in the addin startup function (ThisAddIn_Startup), in the item click event handler or somewhere else? And how to properly unregister the handler if it's eg. registered for each mail item?
Here's some sample code I found (that I'm not sure where to put):
InspectorEvents_10_Event inspectorEvent = selectedItem[1].GetInspector();
inspectorEvent.Close += ItemClosed;
This tutorial also says there are two types of the Close even that I might need to handle
https://sites.google.com/site/xushengxiaotech/Home/http---sites-google-com-site-xushengxiaoshome-home-handling-the-close-event-correctly-using-outlook-object-model
Where do I register the handlers for those?
You need to track Inspectors.NewInspector event (set up the event handler on startup). Then when NewInspector fires, set the event handler for the Inspector.Close event on the new inspector.
Somebody know the VListBox?
It is fast to load item to the listbox.
But I can't get the SelectIndexChanged Event be triggered by set SelectIndex.
Somebody know how to trigger that event by winapi or something else?
VlistBox source code is in the page above.
does the event get fired when you click on the item with a mouse?
if so then it may be by design. also if you are selecting it via code then a better way is not "how to manually trigger the event". consider refactoring the event handling code into a new DoSelectionChanged() method and have the code that calls SelectIndex() call that. in this way the "meaty" stuff that normally would be in an event callback can be used by other methods, not just the callback.
hope that helps
Wy don't you call the EventHandler manually?
vListBox1_selectedIndexChanged(null,null);
In a composite control, how can I make an event fire internally?
Ie. I populate with some data, see that it's in the right condition (only one item) and then fire off my item selected event, calling the source page's OnItemSelected event.
Thanks,
Some controls implement the ISupportInitialize interface, which has the BeginInit()/EndInit() methods. If you're doing batch updates to a control you can block events using BeginInit() and after you're done call EndInit(). Finally you set the selected item to fire the event or invoke the event directly.
Say that I have a web user control that has several drop down lists in it. They are all set to AutoPostBack = true, BUT each SelectedIndexChanged event handler in my control will fire/chain the other SelectedIndexChanged handlers I have defined for the other DDLs. This means that when the user changes a single DDL, the event handlers are chained/fired for several other DDLs. The logic for which events are chained is very complicated, data driven, and can change depending on which list was actually changed by the user. Therefore, it is very difficult to determine which event handler would fire last.
From the page's point of view, I want to subscribe to a single SelectionChanged Event on the user control that will only fire one time per postback and not until all of the event handlers have fired. I don't care which event handlers have fired, only that the state of the control as a whole has changed.
I'm using C# 3.5/ASP.NET 2.0/VisualStudio 2008
How can I go about doing this?
EDIT: Moved clarification into original description. I think the fact that I specified AutoPostBack=true without specifying that chaining was happening was misleading. I apologize for the confusion.
It depends on when you need the event handler to fire in the page lifecycle.
Here's one strategy:
1) In your user control, track the selection changing of your dropdown lists. If the event handler is executed, update your local tracking variables.
2) In your usercontrol's PreRender handler, check your tracking variables and if called for, fire the user control's SelectionChangedEvent.
This strategy will guarantee that the event handling phase of the page lifecycle is done, but has the drawback that your main page won't receive the "SelectionChanged" on your user control until the PreRender phase. This may or may not work for your situation.
If you need to handle the SelectionChanged event for your usercontrol earlier, then you will likely have to put in more complicated tracking logic in your dropdownlist handlers, and add a tracking variable to ensure that the usercontrol's "SelectionChanged" event only ever gets fired once.
I think you need to create a delgate in child control and then reference that delegate into parent control.