I've got a TreeList that's basically like a Photoshop layers palette. It's a hierarchical list with checkboxes to toggle visibility of a document's individual layers. This is done via the BeforeChecked event, which is raised right before the .Checked value toggles.
It works fine, except if you double-click it, at which point it all seems to go haywire.
If you double-click a checkbox once, it toggles the checked value twice (which is the intended behavior), but it doesn't toggle the visibility of the layer twice because it doesn't raise the BeforeChecked twice.
I figured I'd get around this by putting this in the MouseDoubleClick event:
TreeViewHitTestInfo hit = treeLayerPalette.HitTest(e.X, e.Y);
hit.Node.Checked = !(hit.Node.Checked);
This works for all double-clicks except for the first one. So it only raises the BeforeChecked event once (and not the MouseDoubleClick) at first, getting the checkbox out of sync with the visibility of the layer, and then all following double-clicks raise both the BeforeChecked and MouseDoubleClick events (which in turn raises the BeforeChecked event), maintaining that incorrect relationship.
Also, at one point, I put a MessageBox.Show() in the DoubleClick event. Awkwardly enough, it does not actually get shown on a double-click, but instead gets shown on a third click, no matter how much time has elapsed between the actual double-click and the third click. A third click performed 20 seconds after a double-click will raise the MouseDoubleClick event, but the actual double-click won't.
What's actually going on here, and how can I fix it?
this is a problem with Checkbox Enabled treeviews, however there are a few acceptable workrounds..
Firstly: MS know about the problem but refuse to fix it... : http://connect.microsoft.com/VisualStudio/feedback/details/775922/treeview-double-click-bug#details <-- The Bug report....
So there is no way but to workaround it.. simplest been to subclass the Treeview and forcibly disable the dblclick on the checkbox...
answer (on SOF) : c# treeview ignore double click only at checkbox
Hope this helps....
Related
I need your help
as you can see from the screenshot image
I am trying to make a font dialog where i have:
a Label to test the change that will happen when I
click in the checkbox .as you can see I have 3 checkboxs.
the problem is that I cant make all the checkboxs work together
so the text changed to Bold,Italic and underline..help me please
.....
my Form design
i try to use if else statement
and also switch one and still I don't know how to do it that is why i m here
It's a bit unclear, as others have noted, but.. if you are wanting to combine the results of checked and/or unchecked options to display the results of a user's font styling choices?
THEN:
1.) double-click in your V.S. form designer one of the checkboxes, this will create an event handler in your form's C# code file. The function created will be something like checkbox1_checked(object sender, EventArgs e)
2.) In the event handler function that Visual Studio has scaffolded for you, write all the code necessary to consider the .Checked state of all checkbox controls and update your Label1 control appropriately (depending on your goal, this may require custom .NET painting logic that is too much for a beginner to think about)
3.) Go back to the other controls on your design surface, now select them.. keeping an eye on your lower-right 'Properties' panel, (make sure its switched to the 'events' tab - i.e. click the 'lightning bolt' button). Ensure that each of the other radio buttons that do not yet have an event handler get mapped: Find the row in the Properties panel that shows the word "click" (err.. 'checked' event?). When you click into the white space on the row, next to the word 'checked', it will allow you to select the pre-existing "checkbox1_checked" event handler than you created in step 1.
UPDATED:
4.) the end goal is to wire all checkbox controls to the same event handler function in your form's code-behind.. if you double-click each checkbox at design time.. you'll create separate event handlers.. but with some learning (or following my directions above) you can point them all to the same event handler.
Even if I associate the button with a class derived from ICommand, I am still left with figuring out how the button should trigger the CanExecute method and refresh its enabled state. I do know about the CanExecuteChanged event for which a button with an associated command registers, but see the following paragraph for why this is troublesome.
On a plain old dialog consisting of some 10-15 controls, it seems haphazard to have to process every change notification for every single one of those controls, triggering the CanExecuteChanged event on the button's command, causing the button's enabled state to be affected by the CanExecute method's return value. Even stating what needs to be done in the last sentence was quite cumbersome.
There must be a better way of coding a WPF dialog, so that the confirmation button (e.g., OK) is grayed out until all controls have valid information and is enabled at that point in time (i.e., when all controls are properly filled in). Sample code, ideas and pointers to articles would be immensely appreciated.
Thanks
I don't see anything haphazard here. Since your condition is "all controls have valid information", this can occur after any control is edited, and therefore you need to listen to change notifications from all controls.
On a plain old dialog consisting of some 10-15 controls, it seems
haphazard to have to process every change notification for every
single one of those controls,
I don't think so. Every Textbox, checkbox changed event is handled by the same handler, say SetState(), which calculates the overall state of the dialog. Every time a control is edited, the entire state is recalculated.
until all controls have valid information
Then that object would have a boolean property EnableOKButton, let's say, which is set according to the updated state. Then that property is bound to the button's Enabled property so it automagically changes - without dealing with extraneous events.
I have an application in Silverlight and WPF. The error just happens in Silverlight, but same code is used in WPF.
In my application, there is a RibbonBar, with several RibbonGroups. In each RibbonGroup there are at least one RibbonButton. One of those RibbonGroups also contains four TextBox.
Every TextBox has its own OnLostFocus-Handler. When I leave a TextBox the related Handler is raised.
Now, (1) I click into one of those TextBoxes and (2) then click a RibbonButton, OnLostFocus raises and after that the RibbonButton dropdown menu appears. Everything OK.
After that, (3) I click on another RibbonButton. Again OnLostFocus raise, although - imho - it shouldn't.
So it goes on and on. After every action the TextBox keeps(or gets back, don't know) the focus and this causes the OnLostFocus-Handler to raise.
In WPF same code does not raise OnLostFocus again. Just one time, when it really lost focus.
Does anybody know, why this behaviour is that strange in Silverlight. What is really different to WPF, maybe I just have to set a property which default value ist different to WPF.
Thanks in advance.
Try using OnPreviewLostKeyboardFocus. OnLostFocus is for logical focus which you may lose for a variety reasons.
I don't know the reason for sure but I suspect that the problem you're seeing might be because the ribbon bar is in a FocusScope. When you put focus onto something inside of a focus scope then what you end up with can seem like focus bouncing around some. I'm not certain of this answer, focus is very complicated in WPF. Submitting some code samples might help.
This one is a bit tricky to explain.
I have a usercontrol with some textboxes. I also have a menu just above this usercontrol in the same window. Whenever I tab away, the LostFocus fires correctly on the textbox, and this is what I want. Strangely enough, if I click the Menu button on top of my window, the LostFocus event does not fire on the textbox. Is there an elegant way to make sure that my menu properly allows LostFocus to fire on any controls which last had focus?
I also want to avoid having to Update BindingExpressions otherwise I would likely be doing this for N textboxes, which is undesirable.
I can't imagine it is too difficult to achieve this.. I just don't understand how this doesn't work: in most other situations LostFocus always fires.
Any ideas? Thank you.
Is the menu WPF as well or Winforms / UnManaged? If either of the two then the lost focus event does not fire. This can play havoc with WPF controls as many time a save or other data function is being performed from the menu. To counter this I have had to implement multiple ways to combat this. The easiest way was to implement a mouse leave event on the user control itself and perform any actions you require manually in code.
I want to understand event cycles. I have a form with a grid and textboxes. It has a grid, bound to DataTable, and textboxes bound to same table too. I'm trying to debug something and need to know how to identify ALL events fired in the form to see what may solve an issue for me.
Anyhow, unless I explicitly subclass every class on my form, and override / attach to every event to my own event handlers, how can I get / listen to all events being fired during a certain action... Such as changing a "Selected" road in a DataGridView. It obviously updates its own "CurrentRow"... I need to know what / how to maybe FORCE a re-loading of SAME CurrentRow.
Reason: during a form level "Edit Mode", and I change the content in another "Textbox" control, and reject changes, I need it to simulate the current "Record" is reloaded to go back to its original values.
You could fire up a profiler and look at the method call tree.