Bind element inside of datatemplate to parent's property - c#

how can i bind an element inside of a template to a property of its parent like:
<Button Tag="rofl">
<Button.ContentTemplate>
<DataTemplate>
<TextBlock Text="{ HERE I WANT TO BIND TO THE BUTTONS TAG }"/>
</DataTemplate>
</Button.ContentTemplate>
</Button>
Is that possible?

In addition to #Pedro Lamas's answer you can also perform this by the following way:
<Button x:Name="ButtonTemplate" Tag="rofl">
<Button.ContentTemplate>
<DataTemplate>
<TextBlock Text="{Binding Tag, ElementName=ButtonTemplate}"/>
</DataTemplate>
</Button.ContentTemplate>
</Button>
You define a name for your control and access it's property in it's DataTemplate thanks to the ElementName feature.

You should be able to use a RelativeSource with the TemplatedParent to do that:
<TextBlock Text="{Binding Tag, RelativeSource={RelativeSource TemplatedParent}"/>

Related

How to binding other element in ToolTip

I want binding Text in Tooltip but i have one problem, it is binding value is other element controls, therefore i cannot basically get their value through binding.
<TextBlock x:Name="txb2" Text="Hello Stackoverflow"/>
<TextBox Grid.Row="1" TextChanged="TextBox_TextChanged">
<TextBox.ToolTip>
<TextBlock>
<Run Text="{Binding ElementName=txb2, Path=Text}" FontWeight="Bold"/>
</TextBlock>
</TextBox.ToolTip>
</TextBox>
basically I tried binding this code.
If you look at the output you will see an error:
System.Windows.Data Error: 4 : Cannot find source for binding with
reference 'ElementName=txb2'. BindingExpression:Path=Text;
DataItem=null; target element is 'Run' (HashCode=58577354); target
property is 'Text' (type 'String')
You can fix it by using x:Reference:
<TextBlock x:Name="txb2" Text="Hello Stackoverflow"/>
<TextBox Grid.Row="1">
<TextBox.ToolTip>
<TextBlock>
<Run Text="{Binding Source={x:Reference txb2}, Path=Text}" FontWeight="Bold"/>
</TextBlock>
</TextBox.ToolTip>
</TextBox>
As for the difference between ElementName and x:Reference take a look at the following thread. ElementName does not work since Tooltip is not a Ui property, but ElementName only works with Ui Element hierarchy (Visual Tree) when it searches txb2.
Tooltips exist outside the visual tree, so can't reference other controls by name. All that a tooltip knows about is its own PlacementTarget – the UIElement that it is displayed against.
One way to allow the tooltip to reference other controls is to hijack some otherwise unused property of this placement target control (Tag is most often suitable), which can then be referenced by the tooltip.
<TextBox x:Name="txb2" Text="Hello Stackoverflow" Width="200" />
<TextBox Grid.Row="1" Tag="{Binding ElementName=txb2}" Width="200">
<TextBox.ToolTip>
<ToolTip DataContext="{Binding PlacementTarget.Tag, RelativeSource={RelativeSource Self}}">
<TextBlock>
<Run Text="{Binding Text}" FontWeight="Bold" />
</TextBlock>
</ToolTip>
</TextBox.ToolTip>
</TextBox>
if you're using the MVVM design pattern, an alternative method (that doesn't require property hijacking) is to bind to the PlacementTarget's DataContext (usually the ViewModel). You can then bind the tooltip's content to whatever property of that you like.
<ToolTip DataContext="{Binding PlacementTarget.DataContext, RelativeSource={RelativeSource Self}}">
....

Value from Binding ElementName producing empty string

I have a Datagrid which has a DataGridTemplateColumn containing a ListView whose Itemsource is bound to an array of string.
Within that ListView I have defined an ItemTemplate as I want the Foreground of each item in the list to be dependant on condition - so that's applied to a TextBlock.
I want a tooltip to display when each item in the ListView is hovered over, so I have a Tooltip defined in that TextBlock
What I'm trying to do is have that Tooltip display the title/detail about a specific item by using a converter (to get the index of the item in a different list).
For this I need the Tooltip to know the ListView item but I can't seem to get that to work. The TextBlock itself retrieves it using Path=., I have tried naming the TextBlock ListItem and retrieving it as ElementName to no avail - the result is just empty string.
Here's the relevant xaml (with formatting properties removed).
<ListView.ItemTemplate>
<DataTemplate>
<TextBlock x:Name="ListItem" Text="{Binding Path=.}" Foreground="{Binding RelativeSource={RelativeSource Self}, Path=Text, Converter={StaticResource ConvertItemToColour}}">
<TextBlock.ToolTip>
<ToolTip>
<StackPanel Orientation="Vertical">
<Label>
<TextBlock Text="{Binding ElementName=ListItem, Path=Text, Converter={StaticResource ConvertItemToTitle}}"/> <!-- Item Title -->
</Label>
<Label>
<TextBlock/> <!-- Item Description -->
</Label>
</StackPanel>
</ToolTip>
</TextBlock.ToolTip>
</TextBlock>
</DataTemplate>
</ListView.ItemTemplate>
ToolTip, like Popup, is not part of the main visual tree so neither ElementName nor RelativeSource binding will work beyond ToolTip but DataContext inside ToolTip should still be the same as for ListViewItem
<ToolTip>
<StackPanel Orientation="Vertical">
<Label>
<TextBlock Text="{Binding Path=., Converter={StaticResource ConvertItemToTitle}}"/>
</Label>
</StackPanel>
</ToolTip>
Text="{Binding Path=.}" should give you same result inside ToolTip as in DataTemplate

Bind to Parent Object Property with RelativeSource

I've built a WPF based Treeview with
Item
-Subitem
If Subitem is selected, I would like to display also Properties of Item.
<StackPanel Grid.Column="2" DataContext="{Binding ElementName=myTreeView, Path=SelectedItem}">
<TextBox Text="{Binding Path=Name, Mode=TwoWay}" />
<TextBox Text="{Binding RelativeSource={???} Path=Name, Mode=TwoWay}" />
</StackPanel>
I guess I need to use a RelativeSource statement, but not quite sure how to do so.
{Binding RelativeSource={RelativeSource AncestorType={x:Type typeOfAncestor}}, Path=Name, Mode=TwoWay}
JesseJames has given you the correct way to use RelativeSource but the best you will be able to do with RelativeSource is bind to the TreeViewItem itself, which is just the container for your data object i.e ViewModel, meaning you won't be able to access your data objects properties(easily).
I think in this case binding to the container object would break the View-ViewModel approach you are using. Your best bet would be to create a Parent object within your ViewModel and bind to that object. So that now each object in your collection has a reference to it's parent which can now be bound to directly.
<StackPanel Grid.Column="2" DataContext="{Binding ElementName=myTreeView, Path=SelectedItem}">
<TextBox Text="{Binding Path=Name, Mode=TwoWay}" />
<TextBox Text="{Binding Parent.Name}" />
</StackPanel>
Also note that the SelectedItem property returns your data object and not the container.
I looked at your code, try binding simply to Name. It appears that your data context should already be set to the TreeViewItem due to the following line: <StackPanel Grid.Column="2" DataContext="{Binding ElementName=myTreeView, Path=SelectedItem}">. The RelativeResource binding is probably looking further up the logical tree and that's why your binding is failing.

How to access a Checkbox inside Listbox?

I have a listbox and I have set the itemstemplate as shown below.
XAML:
<ListBox ItemsSource="{Binding DataList}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<CheckBox x:Name="CheckBox" HorizontalAlignment="Center" VerticalAlignment="Center" />
<TextBlock x:Name="TextBlock" Text="{Binding Title}" HorizontalAlignment="Center" VerticalAlignment="Center" Margin="10,0,0,10" FontSize="26.667" TextWrapping="Wrap"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
I want to get which all check box has been selected.Is there any way to get checkbox control for each item so that I can check its IsChecked property.
I can think of a way of binding the IsChecked property.But Is there any other way to do it?
Yes. One way to do is to bind the IsChecked property. And if you are using MVVM, probably that's the right way to do it.
Anyways, if you don't want to go the binding way, and assuming you want to iterate over all items of listbox, and prepare a list of checked items, see if this helps:
WPF - Find a Control from DataTemplate in WPF
If you're already binding to the Title property in the item template then it would certainly make sense to bind to IsChecked, too.
If you really need to, you can walk the visual tree by using the VisualTreeHelper to find the CheckBox instances.
Binding the IsChecked property to a boolean property on your object instance contained within DataList would be the simplest and cleanest way. Alternatively, if you want to avoid code behind, then you could write an attached property.
See also How to access a specific item in a Listbox with DataTemplate?
I bet it cannot be simpler than that:
<ListBox SelectionMode="Multiple" >
<ListBox.ItemTemplate>
<DataTemplate>
<CheckBox
IsChecked="{Binding Path=IsSelected, RelativeSource={RelativeSource AncestorType={x:Type ListBoxItem}}}"
Content="{Binding Path=Content, RelativeSource={RelativeSource AncestorType={x:Type ListBoxItem}}}" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>

WPF: How to select parent listbox if user clicked on child listbox

In my application using DataTemplate mechanism I insert into ListBox item another listbox. But is it possible that when selected one listboxitem in parent listbox, the focus may be on another parent listboxitem's child (see picture)
How to do: if one of child listbox in focus (one item from them selected), then parent listboxitem being selected to? Using binding or templating
<DataTemplate x:Key="NotesListBoxDataTemplate" DataType="Note">
<StackPanel Orientation="Vertical">
<StackPanel Orientation="Horizontal">
<TextBox Text="{Binding Path=Title, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"></TextBox>
<my:DatePicker Height="25" Name="datePicker1" Width="115" xmlns:my="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit"
SelectedDate="{Binding LastEdit,
Mode = TwoWay}" />
</StackPanel>
<TextBox Text="{Binding Path=Content, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"></TextBox>
<StackPanel Orientation="Horizontal">
<ListBox Name="ImagesListBox" SelectedIndex="{Binding Mode=OneWayToSource, Source={StaticResource progParameters}, Path=SelectedImage, UpdateSourceTrigger=PropertyChanged}" ItemsSource="{Binding Path=Images}" ItemTemplate="{StaticResource NotesListBoxImagesTemplate}" Style="{StaticResource HorizontalListBox}">
</ListBox>
<StackPanel Orientation="Vertical">
<Button Name="AddImageButon" Content="+" Click="AddImageButon_Click"></Button>
<Button Name="RemoveImageButon" Content="-" Click="RemoveImageButon_Click"></Button>
</StackPanel>
</StackPanel>
</StackPanel>
</DataTemplate>
On the parent ListBox set property IsSynchronizedWithCurrentItem to true, then in the inner ListBoxes set the SelectedItem property to "{Binding SelectedItem ElementName=lbParent}".
Consider using a Converter to help you get specific data that is not accessible thru xaml or if you need to do some caculations.
Hope this helps.

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