I have a TabItem and was previously setting the Header within the object like so,
<TabItem x:Name="Checked_Out_Items" Header="Clients In Use" Height="40" LostFocus="Checked_Out_Items_LostFocus" GotFocus="Checked_Out_Items_GotFocus" BorderThickness="0" >
However, I've run into the problem where there is not a Click event for this Tab. I found a solution where we can insert a label as the header specified here,
how to handle TabItem single click event in WPF?
But, the Label looks nothing like what I need. Here is the Tab Header defined inside the object.
Here's what it looks like with the label
<TabItem x:Name="Checked_Out_Items" Height="40" LostFocus="Checked_Out_Items_LostFocus" GotFocus="Checked_Out_Items_GotFocus" BorderThickness="0" >
<TabItem.Header>
<Label Content="Clients In Use" Height="40" MouseLeftButtonDown="Checked_Out_Items_Clicked" Width="171" />
</TabItem.Header>
Lets separate the concerns a bit.
In order to handle a mouse click event, a control needs to be prepared for receiving this event, it needs to implement a handler and the handler must actually receive the event. In case of TabItem the mouse click event is consumed by the control, without releasing the event to user defined listeners.
On the level of TabItem, the best option would be to handle the PreviewMouseLeftButtonDown event, but this is not an option if event handling shouldn't occur when child controls have their own handling functionality.
So the other option is to handle the MouseLeftButtonDown event before it reaches the TabItem, which means to handle it in a child control of the tab item.
As said, in order to receive the event, the control needs to be ready to receive the event. This means, it needs a Background not null (can be Transparent) and IsHitTestEnabled="True" (which is default in most cases) and it must actually handle the event.
For the showcase, I use a Red instead of Transparent background color. The red area is the place where mouse clicks are captured and handled.
<TabItem Padding="0">
<TabItem.Header>
<Border Height="30" Width="50"
Background="Red" MouseLeftButtonDown="Item_MouseLeftButtonDown">
<ContentPresenter
VerticalAlignment="Center" HorizontalAlignment="Center"
Content="T2"/>
</Border>
</TabItem.Header>
Test Content 2
</TabItem>
Or, in order to have a better separation between header content and click handling, a HeaderTemplate can be used:
<TabItem Header="T3" Padding="0">
<TabItem.HeaderTemplate>
<DataTemplate>
<Border MinHeight="30" MinWidth="50"
Background="Red" MouseLeftButtonDown="Item_MouseLeftButtonDown">
<ContentPresenter
VerticalAlignment="Center" HorizontalAlignment="Center"
Content="{Binding}"/>
</Border>
</DataTemplate>
</TabItem.HeaderTemplate>
Test Content 3
</TabItem>
The issue with any approach that relies on child controls is, that there is still a border of the TabItem and if the user clicks that border, the click will be outside of the child control and the tab will be selected without executing the click handler.
So a different way to handle tab changes (not clicks!) would be to handle the TabControl.SelectionChanged event and filter for events that actually originate from the TabControl and not from some inner content elements.
private void TabControl_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (e.Source == sender)
{
// this selection change is actually issued because of a tab change
}
}
Another thing I just realized: The same condition could be used in TabItem.PreviewMouseLeftButtonDown in order to filter clicks to the tabitem header vs click events originating from the content area.
Edit:
The reason why Label is looking different is, that a font style is active for TabItem and Label is using some of its internal styles, ignoring the TabItem style.
Apparently, there are some serious keyboard and focus issues with WPF WebBrowser control. I've put together a trivial WPF app, just a WebBrowser and two buttons. The app loads a very basic editable HTML markup (<body contentEditable='true'>some text</body>) and demonstrates the following:
Tabbing is misbehaving. User needs to hit Tab twice to see the caret (text cursor) inside WebBrowser and be able to type.
When user switches away from the app (e.g., with Alt-Tab), then goes back, the caret is gone and she is unable to type at all. A physical mouse click into the WebBrowser's window client area is required to get back the caret and keystrokes.
Inconsistently, a dotted focus rectangle shows up around WebBrowser (when tabbing, but not when clicking). I could not find a way to get rid of it (FocusVisualStyle="{x:Null}" does not help).
Internally, WebBrowser never receives the focus. That's true for both logical focus (FocusManager) and input focus (Keyboard). The Keyboard.GotKeyboardFocusEvent and FocusManager.GotFocusEvent events never get fired for WebBrowser (although they both do for buttons in the same focus scope). Even when the caret is inside WebBrowser, FocusManager.GetFocusedElement(mainWindow) points to a previously focused element (a button) and Keyboard.FocusedElement is null. At the same time, ((IKeyboardInputSink)this.webBrowser).HasFocusWithin() returns true.
I'd say, such behaviour is almost too dysfunctional to be true, but that's how it works. I could probably come up with some hacks to fix it and bring it in row with native WPF controls like TextBox. Still I hope, maybe I'm missing something obscure yet simple here. Has anyone dealt with a similar problem? Any suggestions on how to fix this would be greatly appreciated.
At this point, I'm inclined to develop an in-house WPF wrapper for WebBrowser ActiveX Control, based upon HwndHost. We are also considering other alternatives to WebBrowser, such as Chromium Embedded Framework (CEF).
The VS2012 project can be downloaded from here in case someone wants to play with it.
This is XAML:
<Window x:Class="WpfWebBrowserTest.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Width="640" Height="480" Background="LightGray">
<StackPanel Margin="20,20,20,20">
<ToggleButton Name="btnLoad" Focusable="True" IsTabStop="True" Content="Load" Click="btnLoad_Click" Width="100"/>
<WebBrowser Name="webBrowser" Focusable="True" KeyboardNavigation.IsTabStop="True" FocusVisualStyle="{x:Null}" Height="300"/>
<Button Name="btnClose" Focusable="True" IsTabStop="True" Content="Close" Click="btnClose_Click" Width="100"/>
</StackPanel>
</Window>
This is C# code, it has a bunch of diagnostic traces to show how focus/keyboard events are routed and where the focus is:
using System;
using System.Diagnostics;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Threading;
using System.Windows;
using System.Windows.Input;
using System.Windows.Navigation;
namespace WpfWebBrowserTest
{
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
// watch these events for diagnostics
EventManager.RegisterClassHandler(typeof(UIElement), Keyboard.PreviewKeyDownEvent, new KeyEventHandler(MainWindow_PreviewKeyDown));
EventManager.RegisterClassHandler(typeof(UIElement), Keyboard.GotKeyboardFocusEvent, new KeyboardFocusChangedEventHandler(MainWindow_GotKeyboardFocus));
EventManager.RegisterClassHandler(typeof(UIElement), FocusManager.GotFocusEvent, new RoutedEventHandler(MainWindow_GotFocus));
}
private void btnLoad_Click(object sender, RoutedEventArgs e)
{
// load the browser
this.webBrowser.NavigateToString("<body contentEditable='true' onload='focus()'>Line 1<br>Line 3<br>Line 3<br></body>");
this.btnLoad.IsChecked = true;
}
private void btnClose_Click(object sender, RoutedEventArgs e)
{
// close the form
if (MessageBox.Show("Close it?", this.Title, MessageBoxButton.YesNo) == MessageBoxResult.Yes)
this.Close();
}
// Diagnostic events
void MainWindow_GotKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
{
Debug.Print("{0}, source: {1}, {2}", FormatMethodName(), FormatType(e.Source), FormatFocused());
}
void MainWindow_GotFocus(object sender, RoutedEventArgs e)
{
Debug.Print("{0}, source: {1}, {2}", FormatMethodName(), FormatType(e.Source), FormatFocused());
}
void MainWindow_PreviewKeyDown(object sender, KeyEventArgs e)
{
Debug.Print("{0}, key: {1}, source: {2}, {3}", FormatMethodName(), e.Key.ToString(), FormatType(e.Source), FormatFocused());
}
// Debug output formatting helpers
string FormatFocused()
{
// show current focus and keyboard focus
return String.Format("Focus: {0}, Keyboard focus: {1}, webBrowser.HasFocusWithin: {2}",
FormatType(FocusManager.GetFocusedElement(this)),
FormatType(Keyboard.FocusedElement),
((System.Windows.Interop.IKeyboardInputSink)this.webBrowser).HasFocusWithin());
}
string FormatType(object p)
{
string result = p != null ? String.Concat('*', p.GetType().Name, '*') : "null";
if (p == this.webBrowser )
result += "!!";
return result;
}
static string FormatMethodName()
{
return new StackTrace(true).GetFrame(1).GetMethod().Name;
}
}
}
[UPDATE] The situation doesn't get better if I host WinForms WebBrowser (in place of, or side-by-side with WPF WebBrowser):
<StackPanel Margin="20,20,20,20">
<ToggleButton Name="btnLoad" Focusable="True" IsTabStop="True" Content="Load" Click="btnLoad_Click" Width="100"/>
<WebBrowser Name="webBrowser" Focusable="True" KeyboardNavigation.IsTabStop="True" FocusVisualStyle="{x:Null}" Height="150" Margin="10,10,10,10"/>
<WindowsFormsHost Name="wfHost" Focusable="True" Height="150" Margin="10,10,10,10">
<wf:WebBrowser x:Name="wfWebBrowser" />
</WindowsFormsHost>
<Button Name="btnClose" Focusable="True" IsTabStop="True" Content="Close" Click="btnClose_Click" Width="100"/>
</StackPanel>
The only improvement is that I do see focus events on WindowsFormsHost.
[UPDATE] An extreme case: two WebBrowser controls with two carets showing at the same time:
<StackPanel Margin="20,20,20,20">
<ToggleButton Name="btnLoad" Focusable="True" IsTabStop="True" Content="Load" Click="btnLoad_Click" Width="100"/>
<WebBrowser Name="webBrowser" Focusable="True" KeyboardNavigation.IsTabStop="True" FocusVisualStyle="{x:Null}" Height="150" Margin="10,10,10,10"/>
<WebBrowser Name="webBrowser2" Focusable="True" KeyboardNavigation.IsTabStop="True" FocusVisualStyle="{x:Null}" Height="150" Margin="10,10,10,10"/>
<Button Name="btnClose" Focusable="True" IsTabStop="True" Content="Close" Click="btnClose_Click" Width="100"/>
</StackPanel>
this.webBrowser.NavigateToString("<body onload='text.focus()'><textarea id='text' style='width: 100%; height: 100%'>text</textarea></body>");
this.webBrowser2.NavigateToString("<body onload='text.focus()'><textarea id='text' style='width: 100%; height: 100%'>text2</textarea></body>");
This also illustrates that the focus handling issue is not specific to contentEditable=true content.
For anyone else stumbling upon this post and needing to set keyboard focus to the browser control (not a particular element within the control, necessarily), this bit of code worked for me.
First, add a project reference (under Extensions in VS) for Microsoft.mshtml.
Next, whenever you'd like to focus the browser control (say for example, when the Window loads), simply "focus" the HTML document:
// Constructor
public MyWindow()
{
Loaded += (_, __) =>
{
((HTMLDocument) Browser.Document).focus();
};
}
This will place keyboard focus inside the web browser control, and inside the "invisible" ActiveX window, allowing keys like PgUp / PgDown to work on the HTML page.
If you want to, you might be able to use DOM selection to find a particular element on the page, and try to focus() that particular element. I have not tried this myself.
The reason it behaves this way is related to the fact that it's an ActiveX control which itself is a fully windows class (it handles mouse and keyboard interaction). In fact much of the time you see the component used you'll find it is the main component taking up a full window because of this. It doesn't have to be done that way but it presents issues.
Here's a forum discussing the exact same issue and it's causes can be clarified by reading the last commentators article links:
http://social.msdn.microsoft.com/Forums/vstudio/en-US/1b50fec6-6596-4c0a-9191-32cd059f18f7/focus-issues-with-systemwindowscontrolswebbrowser
To outline the issues you're having
Tabbing is misbehaving. User needs to hit Tab twice to see the caret (text cursor) inside WebBrowser and be able to type.
that's because the browser control itself is a window which can be tabbed to. It doesn't "forward" the tab to it's child elements immediately.
One way to change this would be to handle the WM message for the component itself but keep in mind that doing so gets tricky when you want the "child" document inside of it to be able to handle messages.
See: Prevent WebBrowser control from stealing focus? specifically the "answer". Although their answer doesn't account that you can control whether the component interacts through dialogs with the user by setting the Silent property (may or may not exist in the WPF control... not sure)
When user switches away from the app (e.g., with Alt-Tab), then goes back, the caret is gone and she is unable to type at all. A physical mouse click into the WebBrowser's window client area is required to get back the caret and keystrokes.
This is because the control itself has received the focus. Another consideration is to add code to handle the GotFocus event and to then "change" where the focus goes. Tricky part is figuring out if this was "from" the document -> browser control or your app -> browser control. I can think of a few hacky ways to do this (variable reference based on losing focus event checked on gotfocus for example) but nothing that screams elegant.
Inconsistently, a dotted focus rectangle shows up around WebBrowser (when tabbing, but not when clicking). I could not find a way to get rid of it (FocusVisualStyle="{x:Null}" does not help).
I wonder if changing Focusable would help or hinder. Never tried it but I'm going to venture a guess that if it did work it would stop it from being keyboard navigable at all.
Internally, WebBrowser never receives the focus. That's true for both logical focus (FocusManager) and input focus (Keyboard). The Keyboard.GotKeyboardFocusEvent and FocusManager.GotFocusEvent events never get fired for WebBrowser (although they both do for buttons in the same focus scope). Even when the caret is inside WebBrowser, FocusManager.GetFocusedElement(mainWindow) points to a previously focused element (a button) and Keyboard.FocusedElement is null. At the same time, ((IKeyboardInputSink)this.webBrowser).HasFocusWithin() returns true.
People have hit issues with where 2 browser controls both show the focus(well... the caret) or even had a hidden control take the focus.
All in all it's pretty awesome what you can do with the component but it's just the right mix of letting you control/change the behavior along with predefined sets of behavior to be maddening.
My suggestion would be to try to subclass the messages so you can direct the focus control directly through code and bypass it's window from trying to do so.
If there is a way to send mouse click event by location programatically it would be great, but if theres another approach that can solve following problem this it is fine too.
In my situation I got a canvas taking up whole application size (covering it completely) and when user clicks it with mouse I want to hide it, and then pass through this mouse click (taking its location x & y from user) to anything that is under canvas (in my case canvas visibility goes to collapsed so controls under it can be seen now).
I am guessing it is impossible, cause certain features like run silverlight fullscreen can only be done in button click handler (correct me if im wrong here).
But is there a place where I can read about those security based limitations of silverlight UI ?
you have to add an click event handler to your canvas. In this handler you get the x and y positon of your click (via MouseButtonEventArgs) and then you can use the VisualTreeHelper to get your "hit elements".
Lets assume the following xaml:
<Grid x:Name="LayoutRoot" Background="White">
<Button Width="50" Height="50" VerticalAlignment="Top" HorizontalAlignment="Left"/>
<TextBox Text="MyText" Width="200" Height="100" VerticalAlignment="Top" HorizontalAlignment="Left"/>
<Canvas Background="Red" x:Name="MyCanvas" />
</Grid>
with the following code behind:
public MainPage()
{
InitializeComponent();
MyCanvas.AddHandler(MouseLeftButtonUpEvent, new MouseButtonEventHandler(handler), true);
}
void handler(object sender, MouseButtonEventArgs e)
{
var point = new Point(e.GetPosition(this).X, e.GetPosition(this).Y);
var elements = VisualTreeHelper.FindElementsInHostCoordinates(point, this);
foreach (var uiElement in elements)
{
if (uiElement is TextBox){
((TextBox) uiElement).Focus();
break;
}
if(uiElement is Button)
{
//do button stuff here
break;
}
}
MyCanvas.Visibility = Visibility.Collapsed;
MyCanvas.RemoveHandler(MouseLeftButtonUpEvent, new MouseButtonEventHandler(handler));
}
But: In this simple example, you get at about 20 hit elements. But they are sorted in the correct "z-Index". So you can iterate through it and the first interesting element for you is where you could break(Maybe you can do this with LINQ, too). So for me, I know that the first hit TextBox is what I want to focus.
Is this what you need?
BR,
TJ
The book says
The WPF Button class only adds two
simple concepts on top of what
ButtonBase already provides: being a
cancel button or a default button.
These two mechanisms are handy short-
cuts for dialogs. If Button.IsCancel
is setto true on a Button inside a
dialog (that is, a Window shown via
its ShowDialog method), the Window is
automatically closed with a
DialogResult of false. If
Button.IsDefault is set to true,
pressing Enter causes the Button to be
clicked unless focus is explicitly
taken away from it.
But in this sample window
<Window xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
Title="About WPF Unleashed" SizeToContent="WidthAndHeight"
Background="OrangeRed" >
<StackPanel>
<Label FontWeight="Bold" FontSize="20" Foreground="White">
WPF Unleashed (Version 3.0)
</Label>
<Label> 2006 SAMS Publishing</Label>
<Label>Installed Chapters:</Label>
<ListBox>
<ListBoxItem>Chapter 1</ListBoxItem>
<ListBoxItem>Chapter 2</ListBoxItem>
</ListBox>
<TextBox AcceptsReturn="False">HELLO TEXT</TextBox>
<RadioButton>HELLO RADIO BUTTON</RadioButton>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center">
<Button IsCancel="True" MinWidth="75" Margin="10">Cancel</Button>
<Button x:Name="OKBUTTON" IsDefault="True" MinWidth="75" Margin="10">OK</Button>
</StackPanel>
<StatusBar>You have successfully registered this product.</StatusBar>
</StackPanel>
</Window>
If I press Enter or even click it, the modal Window(By ShowDialog()) does not get closed (leave aside the return value).
Is that an error in the book ?
I believe it is an error. IsDefault and IsCancel simply means that some access-key-magic is applied when the window is created, so that the button is clicked when you hit 'Enter' and 'ESC' respectively.
If you want a Window to close - you need to:
(from MSDN )
When a dialog box is accepted, it should return a dialog box result of true, which is achieved by setting the DialogResult property when the OK button is clicked
...
Note that setting the DialogResult property also causes the window to close automatically, which alleviates the need to explicitly call Close.
I have a problem in WPF with validation.
I have a user control which has few textboxes, which are binding to datamodel.
The validation is implemented with IDataErrorInfo.
I want the validation to be triggered only when the user press the button "Submit data", so I used UpdateSourceTrigger="Explicit" with the binding of all those text boxes.
Everything working fine, and the validation only triggered when the user push the button, where I update the datasources.
But that user control can be hidden or shown, and when I changed the visibility from display/ to hidden and then back to display, the validation is triggered.
Is there a way to control the validation on that stage?
This is the code that I am using
The binding to the textbox
<TextBox
AutomationProperties.AutomationId="StreetNameTextBoxId"
Height="20" Margin="0,0,5,0" FontSize="12" Name="_streetNameText"
AcceptsReturn="False" AcceptsTab="False" Focusable="True"
Text="{Binding ElementName=_this, Path=SearchParameters.EnteredAddress, UpdateSourceTrigger=Explicit}">
The code that is executing the validation and search (which is associated to click of a button called "Search")
private void ExecuteSearch() {
_streetNameText.UpdateDataSource();
if (ViewModel.CustomerSpecification.IsValid())
PerformActionInBackground(delegate{PerformSearch();});
}