Why isn't the LostFocus event occurring? - vb.net

With a listbox visible, I have clicked on the windows form hoping to use the listbox.lostfocus event to let me hide the listbox - but the event does not occur. I suppose I can use the form.click event to hide the listbox, but how would I get the form to accept focus?

A Form does not want to receive the focus. It was designed to be a container control, it makes sure that one of its child controls always gets the focus. It is technically possible to whack it over the head and make it lose that behavior:
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
this.SetStyle(ControlStyles.ContainerControl, false);
}
protected override void OnClick(EventArgs e) {
this.Focus();
base.OnClick(e);
}
}
This is however a bad idea. A Form doesn't have any way to indicate that it has the focus, you'll also have to override OnPaint() to do something like draw a focus rectangle. If you don't then the user completely loses track of where the focus is located. Then there's the considerable inconvenience that nothing interesting can happen when the user uses the keyboard, a form doesn't have a use for it.
Don't do this. If you want to make a control disappear then add a menu item, toolbar button or a normal button to your UI. Something the user can click on.

the LostFocus event work when the focus move to another control like textbox,... or when the form all of it lost the focus you can use click event for the form to detect taht

Related

How to make a default button in UWP app using XAML?

I'm trying to declare a button as default in UWP app but receive an error:
The property 'IsDefault' was not found in type 'Button'
How can I make a default button in UWP app?
I down know what IsDefault is in WPF but to get if a button is pressed in UWP you can use CoreWindow.GetForCurrentThread().KeyDown. Create a Method that will be called from when the button is pressed or VirtualKey.Enter is clicked.
public MainPage()
{
this.InitializeComponent();
CoreWindow.GetForCurrentThread().KeyDown += MainPage_KeyDown; ;
}
private void MainPage_KeyDown(CoreWindow sender, KeyEventArgs args)
{
switch (args.VirtualKey)
{
case Windows.System.VirtualKey.Enter:
// handler for enter key
break;
default:
break;
}
}
You can use key down event which you can place on any textbox for example if you are making a login page then probably there will be 2 textboxes for username and password then just add key down event handler to textbox as it will be the last mandatory field like this:
<PasswordBox KeyDown="PasswordKeyDown"/>
then you can handle this event as:
using System.Windows.Input;
private void PasswordKeyDown(object sender, KeyEventArgs e)
{
if (e.Key == Key.Enter)
Login();
}
Hope it will help you :)
There is not easy or clean way to solve your problem because IsDefault is not available for uwp apps.
if you are using MVVM or you want to reuse your code I recommend you to use Behaviors and follow the examples that the other guys posted.
I need a Button which user can invoke by pressing the ENTER key.
In an UWP app, by default a Button can be invoked by pressing the Enter key. So I guess what you want is setting the focus on this Button when there are some other UIElements in your page.
You can refer to Keyboard navigation among UI elements,
By default, the tab order of controls is the same as the order in which they are added to a design surface, listed in XAML, or programmatically added to a container.
To focus on the Button which is not the first element, you can just give the TabIndex="1" property to your Button, this property can make your Button get focus whenever the page is loaded, but if you change the focus on other controls in this page, you will need to reselect this button by mouse clicking, touching or TAB key.

Custom context menu XAML for WP8

I try to implement a custom ContextMenu in a LongListSelector.
I'm not using the ContextMenu from Microsoft.Phone.Controls.Toolkit, it's basically the same as in the Rowi App:
(source: hiddenpineapple.com)
Approach 1
My list item toggles a VisualState on hold and an overlay is shown with controls in it.
The problem
I can't find a way to go back to the default state when the user clicks outside of the list item (as in the default ContextMenu).
Approach 2
I've implemented a custom template for the toolkit ContextMenu which looks exactly the same. I had to move its margin top to -itemHeight, as by default it is below the item.
The problem
The problem with this solution is, that it automatically closes itself when opening and I couldn't figure out how to avoid this.
Another problem was that it didn't work well with TiltEffect.IsTiltEnabled from the Toolkit (visual problems).
I need your help
Any suggestions on how to get this working?
Answer
Thanks to Cheese, now I know how to properly close the menu when the user clicks outside.
His suggestion was to get the coordinates of a Tap event on the current page, and check if it's inside the menu. When not, close the menu.
So I added a Tap listener to the page when the menu opens, and removed it when the menu closes. From the page listener I got the event coordinates and could check if it's inside the control which holds the menu (same size and position). I received the position of the control with Point leftUpperPoint = control.TransformToVisual(page).Transform(new Point(0, 0)) and the rightLowerPoint by adding the ActualWidth and ActualHeight.
But then I realized:
Why should I even calculate if the tap is inside the menu? I always want to close the menu when the user taps anywhere on the screen. If it's outside, yes. If it's on a menu button, yes.
Another modification I made was to listen for MouseLeftButtonDown instead of Tap as it also triggers when the user swipes.
So I removed this code and came up with the following:
private void ToggleMenu(object sender, System.Windows.Input.GestureEventArgs e)
{
PhoneApplicationFrame frame = ((PhoneApplicationFrame)Application.Current.RootVisual);
VisualState state = this.States.CurrentState;
if (state == null || state.Name == "DefaultState")
{
frame.MouseLeftButtonDown += MouseDownDelegate;
this.State = "MenuState";
}
else
{
frame.MouseLeftButtonDown -= MouseDownDelegate;
this.State = "DefaultState";
}
}
private void MouseDownDelegate(object sender, System.Windows.Input.MouseButtonEventArgs e)
{
ToggleMenu(sender, null);
}
This works perfectly!
Thanks to Cheese for the hint.
Something like this by #denniscode http://dotnet.dzone.com/articles/rowi-show-tap-menu
Approach 1 problem
The best solution would be:
Get the menus coordinates, when user makes a tap - you check are tap coordinates on menu or not, if not - dissmiss - simple.
Approach 2 problem
I guess you had some button in a corner and when you tapped on it - nothing happened? And when you dissmissed the Tilt all worked. It seems that tilt works faster than a click, so, tilt changes the button coordinates, and device thiks you have missed/or dragged off
You can use what #ScottIsAFool suggested and maybe create another Dependency Property on your TapMenu control of type UIElement named CloseWhenTappedElement and automatically listen for Tap events inside your control once set. For example
<Grid x:Name="TapArea"/>
<TapMenu CloseWhenTappedElement="{Binding ElementName=TapArea"}/>

VB.NET never get focus on any control

i have developed a simple calculator like in windows calculator,
but unlike in windows calculator, after clicking any button, the focus on that button is still there on the particular clicked button.
so how to never get focus for all buttons on calculator form ... ?
i don't think that it will better to write loose focus code on every button's click event ... so any better solution ?
Without seeing any code of yours, I am going to assume that you have a text box that displays the numbers pressed by the user, so you need to set the focus to the text box once a user clicks a button, like this:
TextBox1.Focus()
Note: If your text box is not named TextBox1, then change the name to whatever your text box is actually named.
Instead of a standard button use an instance of a NoFocusButton class derived from the Standard button. In this class override the ShowFocusCues property and return always false.
Form f = new Form();
// Need to add manually the buttons to your form unless you build a customcontrol
NoFocusButton b = new NoFocusButton();
b.Text = "ClickMe";
f.Controls.Add(b);
f.Show();
// Class derived by the Button control, it is identical but the
// property that control the drawing of the Focus rectangle returns FALSE
// tricking the WinForm system to avoid to draw the focus rectangle
class NoFocusButton : System.Windows.Forms.Button
{
protected override bool ShowFocusCues
{
get
{
return false;
}
}
}
The credit goes to Remove Focus Rectangle from Button

click a textblock without selecting the parent listview item

I'm developing a windows store application with C# and XAML. I am using a ListView to display the collection of data.
Inside the ListView I have a data template which has grids and a TextBlock in the grid. I want to tap/click the TextBlock and give action without selecting the parent ListView item as I already have event to handle the selected ListView item. I don't want both to overlap.
Thanks in advance for any response.
So you want to be able to select the ListViewItem when tapping one part of it, but not the TextBlock? If this is the case, in the TextBlock's Tapped event add e.Handled = true;. This should make it so that it isn't further routed up to the parent ListView.
The other thing you can do (which will likely be a more general solution to whatever you want to do with your ListViewItems) is to not use thing SelectionChanged event and instead handle everything with ItemClick. You can then deduce whether the OriginalSource of the event is indeed your TextBlock. Then, if it's not the TextBlock, change the parent ListView's SelectedItem.
An example for chceking the OriginalSource
public static void ItemClickEvent(object sender, ItemClickEventArgs e)
{
if(e.OriginalSource is TextBlock)
DoNothingOrMaybeTextBlockEvent();
else
{
ListView.SelectedItem = e.ClickedItem;
}
}
Hope this helps.
Edit: Added some example code for the OriginalSource check

How to hide a control from the form while designing in visual studio?

I am designing a settings form for my application as shown below:
A tree view with multiple nodes at the left and I want to have one GroupBox for each node to be displayed at the right whenever a node is selected. I have designed my group box with necessary controls for the first node. The question is, how do I design an another group box in the same place when another item is already there. Is there a way to hide a control from a form during design time?
I have always just changed the Z-Order of the GroupBox or Panel by right clicking on it and sending it to back. Just make sure when you add the other GroupBoxes that you add them to the same Parent. Make their Visible property False and then display the GroupBox you want at runtime by making it Visible.
EDIT: Changed answer to be more relevant.
EDIT #2: I missed the VB tag, translating this should be a trivial task anyway.
If you extend GroupBox like this, you'll have a stock GroupBox which will hide itself at design time.
public class myGroupBox : GroupBox
{
public myGroupBox() { InitializeComponent(); }
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
if (DesignMode) this.Visible = false;
}
}
NOTE: This should work for almost any non-sealed control.