WPF and initial focus - wpf

It seems that when a WPF application starts, nothing has focus.
This is really weird. Every other framework I've used does just what you'd expect: puts initial focus on the first control in the tab order. But I've confirmed that it's WPF, not just my app -- if I create a new Window, and just put a TextBox in it, and run the app, the TextBox doesn't have focus until I click on it or press Tab. Yuck.
My actual app is more complicated than just a TextBox. I have several layers of UserControls within UserControls. One of those UserControls has Focusable="True" and KeyDown/KeyUp handlers, and I want it to have the focus as soon as my window opens. I'm still somewhat of a WPF novice, though, and I'm not having much luck figuring out how to do this.
If I start my app and press the Tab key, then focus goes to my focusable control, and it starts working the way I want. But I don't want my users to have to hit Tab before they can start using the window.
I've played around with FocusManager.FocusedElement, but I'm not sure which control to set it on (the top-level Window? the parent that contains the focusable control? the focusable control itself?) or what to set it to.
What do I need to do to get my deeply-nested control to have initial focus as soon as the window opens? Or better yet, to focus the first focusable control in the tab order?

This works, too:
<Window FocusManager.FocusedElement="{Binding ElementName=SomeElement}">
<DataGrid x:Name="SomeElement">
...
</DataGrid>
</Window>

I had the bright idea to dig through Reflector to see where the Focusable property is used, and found my way to this solution. I just need to add the following code to my Window's constructor:
Loaded += (sender, e) =>
MoveFocus(new TraversalRequest(FocusNavigationDirection.First));
This will automatically select the first control in the tab order, so it's a general solution that should be able to be dropped into any window and Just Work.

Based on the accepted answer implemented as an attached behavior:
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
namespace UI.Behaviors
{
public static class FocusBehavior
{
public static readonly DependencyProperty FocusFirstProperty =
DependencyProperty.RegisterAttached(
"FocusFirst",
typeof(bool),
typeof(FocusBehavior),
new PropertyMetadata(false, OnFocusFirstPropertyChanged));
public static bool GetFocusFirst(Control control)
{
return (bool)control.GetValue(FocusFirstProperty);
}
public static void SetFocusFirst (Control control, bool value)
{
control.SetValue(FocusFirstProperty, value);
}
static void OnFocusFirstPropertyChanged(
DependencyObject obj, DependencyPropertyChangedEventArgs args)
{
Control control = obj as Control;
if (control == null || !(args.NewValue is bool))
{
return;
}
if ((bool)args.NewValue)
{
control.Loaded += (sender, e) =>
control.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
}
}
}
}
Use it like this:
<Window xmlns:Behaviors="clr-namespace:UI.Behaviors"
Behaviors:FocusBehavior.FocusFirst="true">

I found another possible solution. Mark Smith posted a FirstFocusedElement markup extension for use with FocusManager.FocusedElement.
<UserControl x:Class="FocusTest.Page2"
xmlns:FocusTest="clr-namespace:FocusTest"
FocusManager.FocusedElement="{FocusTest:FirstFocusedElement}">

After having a 'WPF Initial Focus Nightmare' and based on some answers on stack, the following proved for me to be the best solution.
First, add your App.xaml OnStartup() the followings:
EventManager.RegisterClassHandler(typeof(Window), Window.LoadedEvent,
new RoutedEventHandler(WindowLoaded));
Then add the 'WindowLoaded' event also in App.xaml :
void WindowLoaded(object sender, RoutedEventArgs e)
{
var window = e.Source as Window;
System.Threading.Thread.Sleep(100);
window.Dispatcher.Invoke(
new Action(() =>
{
window.MoveFocus(new TraversalRequest(FocusNavigationDirection.First));
}));
}
The threading issue must be use as WPF initial focus mostly fails due to some framework race conditions.
I found the following solution best as it is used globally for the whole app.
Hope it helps...
Oran

Had same problem solved it with simple solution:
In the main window:
<Window ....
FocusManager.FocusedElement="{Binding ElementName=usercontrolelementname}"
... />
In the user control:
private void UserControl_GotFocus_1(object sender, RoutedEventArgs e)
{
targetcontrol.Focus();
this.GotFocus -= UserControl_GotFocus_1; // to set focus only once
}

You can easily have the control set itself as the focused element in XAML.
<Window>
<DataGrid FocusManager.FocusedElement="{Binding RelativeSource={RelativeSource Self}}">
...
</DataGrid>
</Window>
I've never tried setting this in a usercontrol and seeing if this works, but it may.

A minimal version of Mizipzor's answer for C# 6+.
public static class FocusBehavior
{
public static readonly DependencyProperty GiveInitialFocusProperty =
DependencyProperty.RegisterAttached(
"GiveInitialFocus",
typeof(bool),
typeof(FocusBehavior),
new PropertyMetadata(false, OnFocusFirstPropertyChanged));
public static bool GetGiveInitialFocus(Control control) => (bool)control.GetValue(GiveInitialFocusProperty);
public static void SetGiveInitialFocus(Control control, bool value) => control.SetValue(GiveInitialFocusProperty, value);
private static void OnFocusFirstPropertyChanged(DependencyObject obj, DependencyPropertyChangedEventArgs args)
{
var control = obj as Control;
if (control == null || !(args.NewValue is bool))
return;
if ((bool)args.NewValue)
control.Loaded += OnControlLoaded;
else
control.Loaded -= OnControlLoaded;
}
private static void OnControlLoaded(object sender, RoutedEventArgs e) => ((Control)sender).MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
}
Use in your XAML:
<Window local:FocusBehavior.GiveInitialFocus="True" />

Above solution was not working as expected for me, I've changed slightly the behavior proposed by Mizipzor as following:
From this part
if ((bool)args.NewValue)
{
control.Loaded += (sender, e) =>
control.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
}
To this
if ((bool)args.NewValue)
{
control.Loaded += (sender, e) => control.Focus();
}
ANd I'm not attaching this behavior to Window or UserControl, but to control I want to focus initially, e.g.:
<TextBox ui:FocusBehavior.InitialFocus="True" />
Oh, sorry for different naming I'm using InitialFocus name for the attached property.
And this is working for me, maybe it could help someone else.

If you are like me, and you are using some frameworks that, somehow, mess up with the basic focus behaviors, and make all solutions above irrelevant, you can still do this :
1 - Note the element which get the focus (whatever it is!)
2 - Add this in your code behind xxx.xaml.cs
private bool _firstLoad;
3 - Add this on the element which get the first focus :
GotFocus="Element_GotFocus"
4 - Add the Element_GotFocus method in the code behind, and specify the WPF named element who need the first focus :
private void Element_GotFocus(object sender, RoutedEventArgs e)
{
if(_firstLoad)
{
this.MyElementWithFistFocus.Focus();
_firstLoad = false;
}
}
5 - Manage the Loaded event
in XAML
Loaded="MyWindow_Loaded"
in xaml.cs
private void MyWindow_Loaded(object sender, RoutedEventArgs e)
{
_firstLoad = true;
this.Element_GotFocus(null, null);
}
Hope this will help as a last resort solution

I also faced the same problem. I had three text boxes inside canvas container and wanted the first text box to be focused when the user control opens. WPF code followed MVVM pattern. I created a separate behavior class for focusing the element and binded it to my view like this.
Canvas behavior code
public class CanvasLoadedBehavior : Behavior<Canvas>
{
private Canvas _canvas;
protected override void OnAttached()
{
base.OnAttached();
_canvas = AssociatedObject as Canvas;
if (_canvas.Name == "ReturnRefundCanvas")
{
_canvas.Loaded += _canvas_Loaded;
}
}
void _canvas_Loaded(object sender, RoutedEventArgs e)
{
FocusNavigationDirection focusDirection = FocusNavigationDirection.Next;
// MoveFocus takes a TraveralReqest as its argument.
TraversalRequest request = new TraversalRequest(focusDirection);
UIElement elementWithFocus = Keyboard.FocusedElement as UIElement;
if (elementWithFocus != null)
{
elementWithFocus.MoveFocus(request);
}
}
}
Code for view
<Canvas Name="ReturnRefundCanvas" Height="200" Width="1466" DataContext="{Binding RefundSearchViewModel}">
<i:Interaction.Behaviors>
<b:CanvasLoadedBehavior />
</i:Interaction.Behaviors>
<uc:Keyboard Canvas.Left="973" Canvas.Top="111" ToolTip="Keyboard" RenderTransformOrigin="-2.795,9.787"></uc:Keyboard>
<Label Style="{StaticResource Devlbl}" Canvas.Left="28" Content="Return and Refund Search" Canvas.Top="10" />
<Image Height="30" Width="28" Canvas.Top="6" Canvas.Left="5" Source="pack://application:,,,/HomaKiosk;component/images/searchF.png">
<Image.OpacityMask>
<ImageBrush ImageSource="pack://application:,,,/HomaKiosk;component/images/searchF.png"/>
</Image.OpacityMask>
</Image>
<Separator Height="4" Canvas.Left="6" Margin="0" Canvas.Top="35" Width="1007"/>
<ContentControl Canvas.Top="45" Canvas.Left="21"
ContentTemplate="{StaticResource ErrorMsg}"
Visibility="{Binding Error, Converter={c:StringNullOrEmptyToVisibilityConverter}}"
Content="{Binding Error}" Width="992"></ContentControl>
<Label Style="{StaticResource Devlbl}" Canvas.Left="29" Name="FirstName" Content="First Name" Canvas.Top="90" />
<wpf:AutoCompleteTextBox Style="{StaticResource AutoComp}" Height="32" Canvas.Left="33" ToolTip="First Name" Canvas.Top="120" Width="205" Padding="10,5" TabIndex="1001"
VerticalAlignment="Top"
Watermark=""
IconPlacement="Left"
IconVisibility="Visible"
Delay="100"
Text="{Binding FirstName, Mode=TwoWay, TargetNullValue=''}"
Provider="{Binding FirstNameSuggestions}">
<wpf:AutoCompleteTextBox.ItemTemplate>
<DataTemplate>
<Border Padding="5">
<StackPanel Orientation="Vertical">
<TextBlock Text="{Binding}"
FontWeight="Bold" />
</StackPanel>
</Border>
</DataTemplate>
</wpf:AutoCompleteTextBox.ItemTemplate>
</wpf:AutoCompleteTextBox>
<Label Style="{StaticResource Devlbl}" Canvas.Left="250" Content="Last Name" Canvas.Top="90" />
<wpf:AutoCompleteTextBox Style="{StaticResource AutoComp}" Height="32" ToolTip="Last Name" Canvas.Left="250" Canvas.Top="120" Width="205" Padding="10,5" TabIndex="1002"
VerticalAlignment="Top"
Watermark=""
IconPlacement="Left"
IconVisibility="Visible"
Delay="100"
Text="{Binding LastName, Mode=TwoWay, TargetNullValue=''}"
Provider="{Binding LastNameSuggestions}">
<wpf:AutoCompleteTextBox.ItemTemplate>
<DataTemplate>
<Border Padding="5">
<StackPanel Orientation="Vertical">
<TextBlock Text="{Binding}"
FontWeight="Bold" />
</StackPanel>
</Border>
</DataTemplate>
</wpf:AutoCompleteTextBox.ItemTemplate>
</wpf:AutoCompleteTextBox>
<Label Style="{StaticResource Devlbl}" Canvas.Left="480" Content="Receipt No" Canvas.Top="90" />
<wpf:AutoCompleteTextBox Style="{StaticResource AutoComp}" Height="32" ToolTip="Receipt No" Canvas.Left="480" Canvas.Top="120" Width="205" Padding="10,5" TabIndex="1002"
VerticalAlignment="Top"
Watermark=""
IconPlacement="Left"
IconVisibility="Visible"
Delay="100"
Text="{Binding ReceiptNo, Mode=TwoWay, TargetNullValue=''}"
Provider="{Binding ReceiptIdSuggestions}">
<wpf:AutoCompleteTextBox.ItemTemplate>
<DataTemplate>
<Border Padding="5">
<StackPanel Orientation="Vertical" >
<TextBlock Text="{Binding}"
FontWeight="Bold">
</TextBlock>
</StackPanel>
</Border>
</DataTemplate>
</wpf:AutoCompleteTextBox.ItemTemplate>
<i:Interaction.Behaviors>
<b:AllowableCharactersTextBoxBehavior RegularExpression="^[0-9]+$" MaxLength="15" />
</i:Interaction.Behaviors>
</wpf:AutoCompleteTextBox>
<!--<Label Style="{StaticResource Devlbl}" Canvas.Left="710" Content="Duration" Canvas.Top="79" />-->
<!--<ComboBox AllowDrop="True" Canvas.Left="710" ToolTip="Duration" Canvas.Top="107" Width="205" TabIndex="1004"
Style="{StaticResource CommonComboBox}"
ItemsSource="{Binding Durations}" DisplayMemberPath="Description" SelectedValuePath="Id" SelectedValue="{Binding SelectedDate, Mode=TwoWay}">
</ComboBox>-->
<Button Content="Search" Style="{StaticResource MyButton}" ToolTip="Search"
Canvas.Top="116" Canvas.Left="710" Cursor="Hand"
Command="{Binding SearchCommand}" TabIndex="2001">
</Button>
<Button Content="Clear" Style="{StaticResource MyButton}" ToolTip="Clear"
Canvas.Top="116" Canvas.Left="840" Cursor="Hand"
Command="{Binding ClearCommand}" TabIndex="2002">
</Button>
<Image Height="25" Width="25" Canvas.Top="175" Canvas.Left="25" Source="pack://application:,,,/HomaKiosk;component/images/chkpending.png"/>
<Label Style="{StaticResource LegendLbl}" Canvas.Left="50" Content="Check Returned and Payment Pending" Canvas.Top="178" />
<Image Height="25" Width="25" Canvas.Top="175" Canvas.Left="300" Source="pack://application:,,,/HomaKiosk;component/images/chkrepaid.png"/>
<Label Style="{StaticResource LegendLbl}" Canvas.Left="325" Content="Repaid" Canvas.Top="178" />
<Image Height="25" Width="25" Canvas.Top="175" Canvas.Left="395" Source="pack://application:,,,/HomaKiosk;component/images/refund.png"/>
<Label Style="{StaticResource LegendLbl}" Canvas.Left="415" Content="Refunded" Canvas.Top="178" />
</Canvas>

<Window FocusManager.FocusedElement="{Binding ElementName=yourControlName}">

Related

How to reach my controller from code-behind

I have this Circle ProgressBar that responds to my Slider value changed:
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center" VerticalAlignment="Center" Margin="530,303,114,303">
<Grid HorizontalAlignment="Center" VerticalAlignment="Center" Height="153" Width="155">
<DesignInControl:CircularProgressBar HorizontalAlignment="Center" VerticalAlignment="Center"
SegmentColor="#FF878889" StrokeThickness="8" Percentage="100" />
<DesignInControl:CircularProgressBar Name="circleVale" HorizontalAlignment="Center" VerticalAlignment="Center"
Percentage="{Binding Value, ElementName=slider}" SegmentColor="#026873" StrokeThickness="8" />
</Grid>
</StackPanel>
<Slider x:Name="slider" Maximum="100" Value="0" Width="200" Margin="597,185,227,495" />
<Label Name="lblCircleProgress" Content="{Binding Value, ElementName=slider}" Margin="698,344,284,343" Foreground="White"
How can I change this value in the code-behind?
I tried to give this control a name property (Name="circleVale") but for some reason I cannot reach it in the code-behind.
Your circleVale control should be accessible in the code behind, but apart from that, i think using SetCurrentValue will leave the binding in place.
Can you change any other property of the progressbar from code?
You have the property Percentage of your CircularProgressBar named "circleVale" bound to the slider's Value. In order to change them from the code behind try to set a depdendency property :
public int SliderValue
{
get { return (int)GetValue(SliderValueProperty); }
set { SetValue(SliderValueProperty, value); }
}
// Using a DependencyProperty as the backing store for SliderValue. This enables animation, styling, binding, etc...
public static readonly DependencyProperty SliderValueProperty =
DependencyProperty.Register("SliderValue", typeof(int), typeof(MainWindow), new PropertyMetadata(0));
private void btnChangeSliderValue_Click(object sender, RoutedEventArgs e)
{
SliderValue = 70;
}
Set the DataContext of your Window in the constructor:
public MainWindow()
{
InitializeComponent();
this.DataContext = this;
}
And this can be an example for your XAML:
<StackPanel>
<Slider x:Name="slider" Maximum="100" Value="{Binding SliderValue}" Width="200"/>
<Button Click="btnChangeSliderValue_Click" HorizontalAlignment="Center" Content="Change slider value" Margin="5,10"/>
</StackPanel>
This way you don't need to access the slider using its name. Using binding is easier and step by step you can reach MVVM.

Silverlight HyperlinkButton styles in custom control

I have a strange styling problem that I cannot figure out.
What I want to achieve is that HyperlinkButtons in datagrid cells are styled with an underline when the mouse hovers the link.
I have one column where I declare the HyperlinkButton element in XAML like this:
<HyperlinkButton Style="{StaticResource HyperlinkButtonStyle}" DataContext="{Binding}" FontSize="11" Content="{Binding DguNr}" Click="DgunrHyperlinkButtonClick" />
This works fine - the link is styled as I want.
In another column, I need to display n number of HyperlinkButtons based on some information in the bound element. Hence I have created a usercontrol that will render 0..n Hyperlinkbuttons. The control is declared in XAML like this:
<sdk:DataGridTemplateColumn IsReadOnly="True" CanUserSort="True">
<sdk:DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<bc:BoreholePlantGridColumn Plants="{Binding Plants, Mode=OneWay}" />
</DataTemplate>
</sdk:DataGridTemplateColumn.CellTemplate>
</sdk:DataGridTemplateColumn>
The code behind for the control looks like this:
public partial class BoreholePlantGridColumn : UserControl, INotifyPropertyChanged
{
public BoreholePlantGridColumn()
{
InitializeComponent();
Loaded += new RoutedEventHandler(BoreholePlantGridColumn_Loaded);
}
void BoreholePlantGridColumn_Loaded(object sender, RoutedEventArgs e)
{
var borehole = (SelectableBoring)this.DataContext;
foreach(var p in borehole.Plants)
{
// <HyperlinkButton HorizontalAlignment="Stretch" VerticalAlignment="Stretch" VerticalContentAlignment="Center" HorizontalContentAlignment="Center" DataContext="{Binding}" Foreground="Black" FontSize="11" Content="{Binding DguNr}" Click="DgunrHyperlinkButtonClick" />
var button = new HyperlinkButton();
button.Content = p.PlantId;
button.Style = (Style)App.Current.Resources["HyperlinkButtonStyle"];
button.VerticalContentAlignment = VerticalAlignment.Center;
var url = String.Format(Common.Constants.Url.GeusPlantLinkTemplate, p.PlantId);
button.NavigateUri = new Uri(url, UriKind.RelativeOrAbsolute);
button.TargetName = "_blank";
LayoutRoot.Children.Add(button);
}
}
public event PropertyChangedEventHandler PropertyChanged;
public static readonly DependencyProperty PlantsProperty = DependencyProperty.Register("Value", typeof(Anlaeg), typeof(BoreholePlantGridColumn), new PropertyMetadata(new PropertyChangedCallback(ValueChanged)));
public IList<Anlaeg> Plants
{
get { return (IList<Anlaeg>)this.GetValue(PlantsProperty); }
set { this.SetValue(PlantsProperty, value); }
}
private static void ValueChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
var myUC = (BoreholePlantGridColumn)obj;
var newValue = (IList<Anlaeg>)e.NewValue;
}
}
This works almost as expected; the linkbuttons(s) are rendered with the correct color - but there is not displayed an underline text when the mouse hovers the link.
I do not understand why the underline is displayed in the hyperlinkbutton that is declared directly in XAML but not in the hyperlink that is rendered in code-behind. Can someone please help me on this?
I have used the hyperlinkbutton styling from this thread:1
I just use the Following Code
<ListBox Grid.Column="1" ItemsSource="{Binding EncyclopediaList}" HorizontalContentAlignment ="Stretch" Margin="5,0" >
<ListBox.ItemTemplate>
<DataTemplate>
<HyperlinkButton Content="{Binding Name}" Foreground="Black" Command="{Binding ViewArticlePageCommand, Source={StaticResource EncyclopediaViewModel}}" CommandParameter="{Binding ServerEncyclopediaID}" FontFamily="Arial" FontSize="18" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
No need to Style the HyperlinkButton its Works perfectly in My Case Add the Underline and Make it bold when Mouse move over it.

Show and focus TextBox in DataTemplate

I have searched high and low, but I can't figure this one out. I am building a ListBox that has editable items. I have a DataTemplate for the ListBox.ItemTemplate that contains (among other things) a TextBlock and a TextBox. The TextBlock is always visible, and the TextBox is only visible after the user double-clicks on the TextBlock. When the user clicks another item in the list, the TextBox hides again to show the TextBlock. All of this works great. See my code:
XAML
<Window.Resources>
<local:GoalCollection x:Key="goals"/>
<DataTemplate x:Key="GoalItemTemplate" DataType="local:Goal">
<Grid>
<TextBlock Text="{Binding Title}"
MouseLeftButtonDown="TextBlock_MouseLeftButtonDown"
VerticalAlignment="Center"/>
<TextBox Name="EntryBox"
Text="{Binding Title}"
Visibility="Hidden"
BorderBrush="{x:Null}"
Padding="-2,0,0,0"
Panel.ZIndex="1"
Margin="-2,0,0,0"/>
</Grid>
</DataTemplate>
</Window.Resources>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition Width="2*" />
</Grid.ColumnDefinitions>
<ListBox Name="GoalsList"
ItemsSource="{Binding Source={StaticResource goals}}"
HorizontalContentAlignment="Stretch"
ItemTemplate="{StaticResource GoalItemTemplate}"
SelectionChanged="GoalsList_SelectionChanged" />
</Grid>
C#
public partial class MainWindow : Window
{
GoalCollection goals;
public MainWindow()
{
InitializeComponent();
}
private childItem FindVisualChild<childItem>(DependencyObject obj)
where childItem : DependencyObject { ... }
protected override void OnInitialized(EventArgs e)
{
base.OnInitialized(e);
goals = (GoalCollection)Resources["goals"];
}
private void TextBlock_MouseLeftButtonDown(object sender,
MouseButtonEventArgs e)
{
if (e.ClickCount == 2)
{
TextBlock tblk = sender as TextBlock;
if (tblk == null)
return;
TextBox tbx = ((Grid)tblk.Parent).FindName("EntryBox") as TextBox;
if (tbx == null)
return;
tbx.Visibility = Visibility.Visible;
Keyboard.Focus(tbx);
}
}
private void GoalsList_SelectionChanged(object sender,
SelectionChangedEventArgs e)
{
ListBoxItem lbi;
ContentPresenter cp;
DataTemplate dt;
TextBox tbx;
foreach (Goal item in e.RemovedItems)
{
lbi = (ListBoxItem)GoalsList.ItemContainerGenerator.
ContainerFromItem(item);
cp = FindVisualChild<ContentPresenter>(lbi);
dt = cp.ContentTemplate;
tbx = (TextBox)dt.FindName("EntryBox", cp);
if (tbx == null)
continue;
tbx.Visibility = Visibility.Hidden;
}
}
}
The problem that I'm having is that the TextBox immediately shifts focus back to the host ListBoxItem after the double-click. An additional (third) click is required to focus on the TextBox.
Tracing through this, I have found that the TextBox does indeed receive focus. But then it immediately loses it (try adding a handler for the TextBox.LostKeyboardFocus event and step through and out of the `TextBlock_MouseLeftButtonDown()' method). Any ideas?
Thanks.
My guess is that the click event is bubbling up to the ListBox and it's handling it by selecting the item.
Try adding this to your Click event handler (after Keyboard.Focus(tbx);)
e.Handled = true;
If you want to give focus to a child element, try the FocusManager.
<DataTemplate x:Key="MyDataTemplate" DataType="ListBoxItem">
<Grid>
<WrapPanel Orientation="Horizontal"
FocusManager.FocusedElement="{Binding ElementName=tbText}">
<CheckBox IsChecked="{Binding Path=Completed}" Margin="5" />
<Button Style="{StaticResource ResourceKey=DeleteButtonTemplate}"
Margin="5" Click="btnDeleteItem_Click" />
<TextBox Name="tbText"
Text="{Binding Path=Text}"
Width="200"
TextWrapping="Wrap"
AcceptsReturn="True"
Margin="5"
Focusable="True"/>
<DatePicker Text="{Binding Path=Date}" Margin="5"/>
</WrapPanel>
</Grid>
</DataTemplate>

Access control within datatemplate

This is XAML:
<Window.Resources>
<DataTemplate x:Key="Temp">
<DockPanel Width="Auto" Background="White" LastChildFill="False">
<TextBox Name="txtBox" TextWrapping="Wrap" DockPanel.Dock="Left" Text="{Binding RelativeSource={RelativeSource AncestorType=ContentControl}, Path=Content}" Height="20" Width="100"/>
<StackPanel Orientation="Vertical">
<RadioButton Content="Option1" HorizontalAlignment="Left" Height="16" Width="112" Click="RadioButton_Click" />
</StackPanel>
</DockPanel>
</DataTemplate>
</Window.Resources>
<Grid>
<ContentControl ContentTemplate="{DynamicResource Temp}" Content="1"/>
</Grid>
This is codebehind:
private void RadioButton_Click(object sender, RoutedEventArgs e)
{
StackPanel sp = ((RadioButton)sender).Parent as StackPanel;
DockPanel dp = sp.Parent as DockPanel;
TextBox txtbox = dp.FindName("txtBox") as TextBox;
MessageBox.Show(txtbox.Text);
}
Is there a more simple way to access the textbox?
(As I know I can't get Parent of parent e.g. Parent.Parent...)
Your code is not that complex!
However, you could simplify it by using Linq-to-VisualTree:
private void RadioButton_Click(object sender, RoutedEventArgs e)
{
RadioButton rb = sender as RadioButton;
TextBox txtbox= rb.Ancestors<DockPanel>().First().Elements<TextBox>().First() as TextBox;
MessageBox.Show(txtbox.Text);
}
The Linq query above finds the first DockPanel ancestor of your RadioButton (i.e. the Parent.Parent that you wanted!), then finds the first TextBox child of the DockPanel.
However, I typically use Linq-to-VisualTree in cases where the query is more complex. I thin your approach is OK really!
Among other things you can add a reference to it in the RadioButton.Tag:
<RadioButton Content="Option1" HorizontalAlignment="Left" Height="16" Width="112"
Click="RadioButton_Click" Tag="{x:Reference txtBox}" />
private void RadioButton_Click(object sender, RoutedEventArgs e)
{
var textBox = (sender as FrameworkElement).Tag as TextBox;
//...
}

Silverlight: Define event handler in hierarchical data template

I am having problems getting at a click event of a button and am using Silverlight 3.0 w/ matching Silverlight Toolkit.
Problem
I have this TreeView:
TreeView sample http://a.imagehost.org/0939/TreeView.png.
The value for a certain node is the sum of the values of its children. Only in leaves can data be added (for the time being).
What I want to achieve is that a user can add (and eventually remove) entries in the tree to eventually create a custom diagram.
To that end I would like the "plus sign" to insert a new line / node as child of the node where the user clicked. (I.e. if I click the plus at "Display", I get a line below to specify CRT or TFT or whatever.)
Thing is, for all my brain is worth, I don't know how to receive any useful event.
The TextBlock, TextBox and Button are defined in a hierarchical template and I can't define a Click-handler in that template.
OTOH, I haven't found a way to get at the template items of a certain TreeViewItem from within (c#) code. Very well am I able to do trv.ItemContainerGenerator.GetContainerFromItem(item), and as Justin Angel showed I can very well change the font size, but didn't find any way to access the textbox or button.
Is there any way to capture the click event to the button? Or any alternative way of getting something that gives the "add below" functionality?
Thank you in advance.
More Data
The treeview xaml is this:
<controls:TreeView x:Name="SankeyDataTree"
ItemTemplate="{StaticResource SankeyTreeTemplate}" BorderThickness="0"
Background="{x:Null}" HorizontalAlignment="Left" VerticalAlignment="Top">
<controls:TreeViewItem IsExpanded="True">
<controls:TreeViewItem.HeaderTemplate>
<DataTemplate>
<TextBlock Text="Loading..."/>
</DataTemplate>
</controls:TreeViewItem.HeaderTemplate>
</controls:TreeViewItem>
</controls:TreeView>
I use this HierarchicalDataTemplate (and stole the appraoch from Timmy Kokke):
<Data:HierarchicalDataTemplate x:Key="SankeyTreeTemplate" ItemsSource="{Binding Children}">
<Grid Height="24">
<Grid.ColumnDefinitions>
<!-- ... -->
</Grid.ColumnDefinitions>
<TextBlock Text="{Binding Path=Value.name, Mode=TwoWay}" VerticalAlignment="Center"/>
<TextBox Text="{Binding Path=Value.flow, Mode=TwoWay}" Margin="4,0" VerticalAlignment="Center" d:LayoutOverrides="Width" Grid.Column="1" TextAlignment="Right" Visibility="{Binding Children, Converter={StaticResource BoxConverter}, ConverterParameter=\{box\}}"/>
<TextBlock Text="{Binding Path=Value.throughput, Mode=TwoWay}" Margin="4,0" VerticalAlignment="Center" d:LayoutOverrides="Width" Grid.Column="1" TextAlignment="Right" Visibility="{Binding Children, Converter={StaticResource BoxConverter}, ConverterParameter=\{block\}}"/>
<Button Margin="0" Grid.Column="2" Style="{StaticResource TreeViewItemButtonStyle}">
<Image Source="../Assets/add.png" Margin="0" HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Button>
</Grid>
</Data:HierarchicalDataTemplate>
To this TreeView is bound a "SimpleTree", whose Values hold basically onle a string (name) and two doubles (flow and throughput).
public String name { get; set; }
public Double flow { get; set; }
public Double throughput { get; set; }
(Plus the code for the INotifyPropertyChanged to get a twoway bind to the text boxes.)
You can attach a Behavior to the Button in the HierarchicalDataTemplate and let that handle Click events from the Button.
Download and install the Expression Blend 3 SDK. Add a reference to System.Windows.Interactivity in the project and add a Behavior attached to a Button:
public class ButtonClickBehavior : Behavior<Button> {
protected override void OnAttached() {
base.OnAttached();
AssociatedObject.Click += ButtonClick;
}
protected override void OnDetaching() {
base.OnDetaching();
AssociatedObject.Click -= ButtonClick;
}
void ButtonClick(object sender, RoutedEventArgs e) {
Node node = AssociatedObject.DataContext as Node;
if (node != null) {
// Button clicked. Do something to associated node.
}
}
}
Attach the Behavior to the Button in the HierarchicalDataTemplate (assuming this namespace declaration: xmlns:interactivity="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"):
<Button Margin="0" Grid.Column="2" Style="{StaticResource TreeViewItemButtonStyle}">
<Image Source="../Assets/add.png" Margin="0" HorizontalAlignment="Center" VerticalAlignment="Center"/>
<interactivity:Interaction.Behaviors>
<local:ButtonClickBehavior/>
</interactivity:Interaction.Behaviors>
</Button>
If desired you can add properties to ButtonClickBehavior and set those from XAML to create a more reusable Behavior.
You can handle the button click event in the code behind. To get to the data, just bind it to the Tag attribute.
<Button Margin="0" Grid.Column="2"
Click="Button_Click" Tag="{Binding}"
Style="{StaticResource TreeViewItemButtonStyle}">
<Image Source="../Assets/add.png" Margin="0"
HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Button>
In the code behind, handle it and access the element.
private void Button_Click(object sender, RoutedEventArgs e)
{
var data = ((Button)sender).Tag as SimpleTreeNode
}
Where SimpleTreeNode is the name of your tree element class.
You should be able to add a new node to the data found now.

Resources