Setting attached properties on parent ContentPresenter from a DataTemplate - wpf

I have a Grid and somewhere in it a ContentControl:
<Grid Name="OuterGrid">
<!-- some controls on the grid -->
<ContentControl Name="dbg1" Content="{Binding Mode=OneWay}" ContentTemplateSelector="{StaticResource SBATemplateSelector}"></ContentControl>
<!-- some more controls on the grid -->
</Grid>
The templateselector is not really interesting:
<src:SBATemplateSelector x:Key="SBATemplateSelector"
NormalTemplate="{StaticResource SBAreaTemplate1}"
BigTemplate="{StaticResource SBAreaTemplate2}" />
But from the templates I'd like to give the content and position it in 'OuterGrid', by setting the Grid.Row etc. attached properties:
<DataTemplate x:Key="SBAreaTemplate1" DataType="src:XCViewModel">
<DataTemplate.Resources>
<Style TargetType="ContentPresenter"> <!-- should go for only the 'parent' contentpresenter -->
<Setter Property="Grid.Row" Value="4" />
<Setter Property="Grid.Column" Value="0" />
<Setter Property="Grid.RowSpan" Value="5" />
<Setter Property="Grid.ColumnSpan" Value="10" />
</Style>
</DataTemplate.Resources>
<Border Name="sbAreaBorder" BorderThickness="1" BorderBrush="Black">
<ScrollViewer Name="sblbScroller" HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto">
<StackPanel Orientation="Vertical">
<ItemsControl Name="notRelevantListBox" ItemsSource="{Binding}" ItemTemplateSelector="{StaticResource NotRelevantSelector}" />
</StackPanel>
</ScrollViewer>
</Border>
</DataTemplate>
so I don't even want Binding, just setting properties to static values. No matter what I do I can't get the properties to take effect on the ContentPresenter of the DataTemplate.
There are almost usable solutions (e.g. https://social.msdn.microsoft.com/Forums/vstudio/en-US/cc9ed724-600e-415a-b775-bae09eea66f8/cant-use-attached-properties-inside-a-datatemplate?forum=wpf) but they always apply an ItemsControl - I don't have an ItemsControl, I want the positioning to work for the whole DataTemplate.

The ContentTemplate cannot set the Grid.Row and Grid.Column attached property of the ContentControl. The template is only applied to the Content of the ContentControl.
But you could to this programmatically in your ContentTemplateSelector:
public class SBATemplateSelector : DataTemplateSelector
{
public override DataTemplate SelectTemplate(object item, DependencyObject container)
{
if (item != null)
{
ContentPresenter cp = container as ContentPresenter;
if (cp != null)
{
ContentControl cc = VisualTreeHelper.GetParent(cp) as ContentControl;
if (cc != null)
{
Grid.SetRow(cc, 4);
Grid.SetColumn(cc, 0);
Grid.SetRowSpan(cc, 5);
Grid.SetColumnSpan(cc, 10);
}
}
}
...
}
}

Related

wpf combobox not binding to collection when inside ContentTemplate

I'm trying show a certain control based on a property (combobox or textbox). So I have this contentcontrol implemented:
<!--<ComboBox MaxWidth="200" Background="#333333" ItemsSource="{Binding ModelObjectWrapper.Values}" Grid.Row="1" Grid.Column="1"/>-->
<ContentControl Grid.Row="1" Grid.Column="1">
<ContentControl.Resources>
<Style TargetType="ContentControl">
<Style.Triggers>
<DataTrigger Binding="{Binding ModelObjectWrapper.ObjType}" Value="typeA">
<Setter Property="ContentTemplate">
<Setter.Value>
<DataTemplate>
<ComboBox HorizontalAlignment="Left" MaxWidth="200" Background="#333333" ItemsSource="{Binding ModelObjectWrapper.Values, UpdateSourceTrigger=PropertyChanged}"/>
</DataTemplate>
</Setter.Value>
</Setter>
</DataTrigger>
<DataTrigger Binding="{Binding ModelObjectWrapper.ObjType}" Value="typeB">
<Setter Property="ContentTemplate">
<Setter.Value>
<DataTemplate>
<TextBox />
</DataTemplate>
</Setter.Value>
</Setter>
</DataTrigger>
</Style.Triggers>
</Style>
</ContentControl.Resources>
</ContentControl>
The problem is that the combobox is not showing any items when its part of a controltemplate, and I know the bound list does have them, so I'm assuming the combobox is not being bound to the ItemsSource correctly.
The first line (having only a combobox without the templates), commented out, works fine. Am I not doing the binding right? Could it be that because its part of a datatrigger, it's not getting the right DataContext? I must note that the DataTrigger itself works great (IE showing a combobox if *.ObjType == "typeA".
The VM is a wrapper class around an object:
public class ModelObjectWrapper : ViewModelBase
{
private theModelObject model_obj;
public ModelObjectWrapper(theModelObject obj)
{
model_obj = obj;
}
public ObservableCollection<string> Values
{
get { return model_obj.Values; }
set
{
if (value == model_obj.Values)
return;
model_obj.Values = value;
OnPropertyChanged();
}
}
}
The DataContext of the root element in a ContentControl is the Content of the same ContentControl. Try to use a RelativeSource to bind to a property of the ContentControl's DataContext:
<ComboBox HorizontalAlignment="Left" MaxWidth="200" Background="#333333"
ItemsSource="{Binding DataContext.ModelObjectWrapper.Values, RelativeSource={RelativeSource AncestorType=ContentControl}}"/>
By the way, there is no point setting the UpdateSourceTrigger of an ItemsSource binding to PropertyChanged because the ComboBox never sets the source property.

Change WPF UserControl depending on a Property of a TreeViewItem

My application shows a TreeView on the left with hierarchical ordered items which are all the same type. All the items have a dependency property which can have one of two values. This value is an enum. Depending on this value I want to show one of two UserControls on the left. My idea was to insert both controls and set their opacity to 0. Then I wanted to insert a Style with a DataTrigger that triggers the opacity depending on the enum's value. But I can not access the properties of one control from the other control's DataTrigger; and the trigger does not seem to recognize the enum's value.
The enum:
public enum IdentityType
{
Person,
OrganisationUnit
}
The XAML:
<TreeView Grid.Column="0" Grid.Row="1" Background="AntiqueWhite" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" ItemsSource="{Binding Identities}" x:Name="OiTree">
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Childs}">
<TextBlock Text="{Binding}"/>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>
<Controls:UcPerson Grid.Column="1" Grid.Row="1" Opacity="0">
<Controls:UcPerson.Style>
<Style TargetType="Controls:UcPerson">
<Style.Triggers>
<DataTrigger Binding="{Binding Path=Type, ElementName=OiTree.SelectedItem}" Value="Person">
<Setter Property="Opacity" Value="1"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Controls:UcPerson.Style>
</Controls:UcPerson>
<Controls:UcOrgUnit Grid.Column="1" Grid.Row="1" Opacity="0">
<Controls:UcOrgUnit.Style>
<Style TargetType="Controls:UcOrgUnit">
<Style.Triggers>
<DataTrigger Binding="{Binding Path=Type, ElementName=OiTree.SelectedItem}" Value="OrganisationUnit">
<Setter Property="Opacity" Value="1"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Controls:UcOrgUnit.Style>
</Controls:UcOrgUnit>
The problem is that you are setting the Opacity directly on the control first.
An explicit setting on a control will always override a trigger value.
However, a trigger value will override a style setter.
The following code should work (though I haven't tested it myself)
<Controls:UcPerson Grid.Column="1" Grid.Row="1">
<Controls:UcPerson.Style>
<Style TargetType="Controls:UcPerson">
<Style.Setters>
<Setter Property="Opacity" Value="0" />
</Style.Setters>
<Style.Triggers>
<DataTrigger Binding="{Binding Path=Type, ElementName=OiTree.SelectedItem}" Value="Person">
<Setter Property="Opacity" Value="1"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Controls:UcPerson.Style>
See this question here for another example of the problem: DataTrigger not firing
As an aside, I believe your problem could be solved more elegantly using a DataTemplateSelector.
As Andrew implied the solution to my problem was a DataTemplateSelector. Instead of two userControls I created two templates and Used a ContentControl. The content Property of the ContentControl is bound to the SelectedItem of the TreeView and I implemented a simple DataTemplateSelector which casts the content to the original object an decides wich template to use. The source (modified) is from here: link
This is the xaml:
<Window.Resources>
<DataTemplate x:Key="borderTemplate">
<Border BorderThickness="1" BorderBrush="Brown" CornerRadius="5">
<TextBlock Margin="5" Text="Border Template"/>
</Border>
</DataTemplate>
<DataTemplate x:Key="twoTextBlockTemplate">
<StackPanel>
<TextBlock Margin="5" Text="First TextBlock"/>
<TextBlock Margin="5" Text="Second TextBlock"/>
</StackPanel>
</DataTemplate>
<vm:OiContentTemplateSelector
x:Key="myContentTemplateSelector"
BorderTemplate="{StaticResource borderTemplate}"
TwoTextBlockTemplate="{StaticResource twoTextBlockTemplate}"/>
</Window.Resources>
This is the DataTemplateSelector:
public class OiContentTemplateSelector : DataTemplateSelector
{
public DataTemplate BorderTemplate
{ get; set; }
public DataTemplate TwoTextBlockTemplate
{ get; set; }
public override DataTemplate SelectTemplate(object item, DependencyObject container)
{
OrganisationIdentity value = item as OrganisationIdentity;
if (value != null)
{
if (value.Type == IdentityType.Person)
return BorderTemplate;
else if (value.Type == IdentityType.OrganisationUnit)
return TwoTextBlockTemplate;
return base.SelectTemplate(item, container);
}
else
return base.SelectTemplate(item, container);
}
}
Perhaps this helps somebody

WPF ListBox selection issues, providing feedback to user

I'm trying to create a listbox that shows a thumbnail view of page content, for an app with one canvas but multiple 'pages'. Yes, that's probably not the best place to start from but for historical reasons that's what I have.
I've implemented the ListBox with data binding to a singleton 'WorkBook' that has an ObservableCollection of PageData (everything that appears on a page, including it's background).
What I really really want is to be able to change the Border colour of a ListBoxItem when it's selected and keep that Border colour while it's content is the currently selected item in the class that hosts the collection.
My problems are:-
1/ I can't get the ListBox to select the 1st item on program startup.
2/ when the ListBox loses focus the SelectedIndex is always -1 (so no selection)
3/ adding to the ListBox results in no selection (SelectedIndex == -1)
4/ using triggers, I can set the border of the selectedItem but this is lost when the ListBox loses focus. As the ListBoxItem shows an image that is opaque the 'standard' way of making selection colours stay when out of focus doesn't work - ie
<Style x:Key="PsThumb">
<Style.Resources>
<SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" Color="White"></SolidColorBrush>
<SolidColorBrush x:Key="{x:Static SystemColors.ControlBrushKey}" Color="White"></SolidColorBrush>
</Style.Resources>
</Style>
My code for the ListBox is as follows :-
<ListBox x:Name="PageSorter" Style="{StaticResource PsThumb}" Width="148" BorderThickness="4" HorizontalContentAlignment="Stretch" ScrollViewer.HorizontalScrollBarVisibility="Disabled"
VerticalAlignment="Stretch" ItemsSource="{Binding Pages,Source={StaticResource WorkBook}}" SelectedItem="{Binding Path=CurrentPageData, Mode=TwoWay}"
AllowDrop="True" ScrollViewer.VerticalScrollBarVisibility="Auto">
<ListBox.ItemTemplate>
<DataTemplate>
<Grid>
<Border x:Name="border" BorderBrush="DarkGray" BorderThickness="4" Margin="2,4,2,4" CornerRadius="5">
<Border.Effect>
<DropShadowEffect ShadowDepth="6"/>
</Border.Effect>
<Image Source="{Binding Thumbnail}" Width="130" Height="95" Stretch="Fill"/>
</Border>
</Grid>
<DataTemplate.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ListBoxItem}},Path=IsSelected}" Value="True">
<Setter TargetName="border" Property="BorderBrush" Value="Red"></Setter>
</DataTrigger>
</DataTemplate.Triggers>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
The simplest way to achieve what you're asking is to bind the DataTrigger to a property inside the items of the ListBox. In the example below, I added the Selected property on my Contact class:
public class Contact : INPCBase
{
public string Name { get; set; }
private bool _Selected;
public bool Selected
{
get { return _Selected; }
set
{
_Selected = value;
NotifyPropertyChanged("Selected");
}
}
}
I then bind my ListBox to a List<Contact>. When the user checks the CheckBox, we change the Selected property and in turn trigger the Style:
<Window x:Class="WpfApp.ListboxKeepSelectionWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="ListboxKeepSelectionWindow" Height="277" Width="343"
xmlns:me="clr-namespace:WpfApp">
<Window.Resources>
<me:ContactList x:Key="sample"/>
<Style TargetType="ListBoxItem" x:Key="SelectedListBoxItemStyle">
<Style.Triggers>
<DataTrigger Binding="{Binding Path=Selected}" Value="True">
<Setter Property="BorderBrush" Value="Orange"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Window.Resources>
<Grid>
<ListBox Name="lbxContacts"
ItemsSource="{StaticResource ResourceKey=sample}"
SelectionMode="Extended"
ItemContainerStyle="{StaticResource ResourceKey=SelectedListBoxItemStyle}"
SelectionChanged="lbxContacts_SelectionChanged">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<CheckBox IsChecked="{Binding Path=Selected}">
<TextBlock Text="{Binding Path=Name}"/>
</CheckBox>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
To allow the user to select items without using the checkbox, I added this small event on the ListBox. Since the Contact class implements the INotifyPropertyChanged interface, the value of the CheckBox is updated so the user knows the selection worked:
private void lbxContacts_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
foreach (Contact c in e.AddedItems)
{
c.Selected = !c.Selected;
}
}
When you want to get a list of selected items, you just use a LINQ query on the ItemsSource to get items where Selected == true.

Specify ControlTemplate for ItemsControl.ItemContainerStyle

The following is similar to what I'm trying to accomplish. However, I get the error
Invalid PropertyDescriptor value.
on the Template Setter. I suspect it's because I didn't specify a TargetType for the Style; however, I don't know the container type for ItemsControl.
<ItemsControl>
<ItemsControl.ItemContainerStyle>
<Style>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<StackPanel>
<TextBlock Text="Some Content Here" />
<ContentPresenter />
<Button Content="Edit" />
</StackPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ItemsControl.ItemContainerStyle>
<!-- heterogenous controls -->
<ItemsControl.Items>
<Button Content="Content 1" />
<TextBox Text="Content 2" />
<Label Content="Content 3" />
</ItemsControl.Items>
</ItemsControl>
You can qualify the property name with the type name:
<Setter Property="Control.Template">
The container for ItemsControl is normally a ContentPresenter, but if the child is a UIElement then it won't use a container. In this case, all of the children are Controls, so the ItemContainerStyle will apply to them directly. If you added an item other than a UIElement, that setter would set the Control.Template property on the ContentPresenter, which would succeed but have no effect.
Actually, it sounds like what you want is to wrap each child in a container, even if they are already a UIElement. To do that, you will have to use a subclass of ItemsControl. You could use an existing one like ListBox, or you could subclass ItemsControl and override GetContainerForItemOverride and IsItemItsOwnContainerOverride to wrap the items in your own container. You could wrap them in a ContentControl and then use that as the TargetType for the Style.
public class CustomItemsControl
: ItemsControl
{
protected override DependencyObject GetContainerForItemOverride()
{
return new ContentControl();
}
protected override bool IsItemItsOwnContainerOverride(object item)
{
// Even wrap other ContentControls
return false;
}
}
You will also need to set the TargetType on the ControlTemplate so that the ContentPresenter will bind to the Content property:
<ControlTemplate TargetType="ContentControl">
Also if you only want to do all of it with XAML you can simply use ListBox instead of ItemsControl and define a style for ListBoxItem:
<ListBox ItemsSource="{Binding Elements.ListViewModels}">
<ListBox.Resources>
<Style TargetType="ListBoxItem">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ListBoxItem">
<StackPanel>
<TextBlock>Some Content Here</TextBlock>
<ContentPresenter Content="{TemplateBinding Content}" />
<Button>Edit</Button>
</StackPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ListBox.Resources>
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel />
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
</ListBox>
Note that because I am using ListBox the container is ListBoxItem(Generally the container for WPF's default list control is always named the Item) so we create a style for ListBoxItem:
<Style TargetType="ListBoxItem">
Then we create a new ControlTemplate for ListBoxItem. Please note that ContentPresenter is not used as it always appears in articles and tutorials, you need to template-bind it to Content property of ListBoxItem, so it will show the content for that item.
<ContentPresenter Content="{TemplateBinding Content}" />
I just had the same problem and fixed it this way. I dont wanted some functionalities of ListBox ( item selection ) and by using this technique the item selection does not work anymore.

How can I use a custom TabItem control when databinding a TabControl in WPF?

I have a custom control that is derived from TabItem, and I want to databind that custom TabItem to a stock TabControl. I would rather avoid creating a new TabControl just for this rare case.
This is what I have and I'm not having any luck getting the correct control to be loaded. In this case I want to use my ClosableTabItem control instead of the stock TabItem control.
<TabControl x:Name="tabCases" IsSynchronizedWithCurrentItem="True"
Controls:ClosableTabItem.TabClose="TabClosed" >
<TabControl.ItemTemplate>
<DataTemplate DataType="{x:Type Controls:ClosableTabItem}" >
<TextBlock Text="{Binding Path=Id}" />
</DataTemplate>
</TabControl.ItemTemplate>
<TabControl.ContentTemplate>
<DataTemplate DataType="{x:Type Entities:Case}">
<CallLog:CaseReadOnlyDisplay DataContext="{Binding}" />
</DataTemplate>
</TabControl.ContentTemplate>
</TabControl>
EDIT: This is what I ended up with, rather than trying to bind a custom control.
The "CloseCommand" im getting from a previous question.
<Style TargetType="{x:Type TabItem}" BasedOn="{StaticResource {x:Type TabItem}}" >
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type TabItem}">
<Border
Name="Border"
Background="LightGray"
BorderBrush="Black"
BorderThickness="1"
CornerRadius="25,0,0,0"
SnapsToDevicePixels="True">
<StackPanel Orientation="Horizontal">
<ContentPresenter x:Name="ContentSite"
VerticalAlignment="Center"
HorizontalAlignment="Center"
ContentSource="Header"
Margin="20,1,5,1"/>
<Button
Command="{Binding Path=CloseCommand}"
Cursor="Hand"
DockPanel.Dock="Right"
Focusable="False"
Margin="1,1,5,1"
Background="Transparent"
BorderThickness="0">
<Image Source="/Russound.Windows;component/Resources/Delete.png" Height="10" />
</Button>
</StackPanel>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsSelected" Value="True">
<Setter Property="FontWeight" Value="Bold" />
<Setter TargetName="Border" Property="Background" Value="LightBlue" />
<Setter TargetName="Border" Property="BorderThickness" Value="1,1,1,0" />
<Setter TargetName="Border" Property="BorderBrush" Value="DarkBlue" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
found a way,
derive a class from TabControl and override this function, in my case I want the items of the tab control (when bound) to be CloseableTabItems
public class CloseableTabControl : TabControl
{
protected override DependencyObject GetContainerForItemOverride()
{
return new CloseableTabItem();
}
}
HTH Someone
Sam
You don't want to set the DataType of the DataTemplate in this case. The value of the ItemTemplate property is used whenever a new item needs to be added, and in the case of a tab control it will be used to create a new TabItem. You should declare an instance of your class within the DataTemplate itself:
<TabControl x:Name="tabCases" IsSynchronizedWithCurrentItem="True" Controls:ClosableTabItem.TabClose="TabClosed">
<TabControl.ItemTemplate>
<DataTemplate>
<Controls:ClosableTabItem>
<TextBlock Text="{Binding Path=Id}" />
</Controls:ClosableTabItem>
</DataTemplate>
</TabControl.ItemTemplate>
<TabControl.ContentTemplate>
<DataTemplate DataType="{x:Type Entities:Case}">
<CallLog:CaseReadOnlyDisplay DataContext="{Binding}" />
</DataTemplate>
</TabControl.ContentTemplate>
</TabControl>
This will cause a new ClosableTabItem to be created whenever a new tab is added to the TabControl.
Update; From your comment, it sounds like that the ItemTemplate controls what is created within the TabItem, rather than changing the TabItem itself. To do what you want to do, but for a TreeView, you would set the HeaderTemplate. Unfortunately, I don't see a HeaderTemplate property of TabControl.
I did some searching, and this tutorial modifies the contents of the tab headers by adding controls to TabItem.Header. Maybe you could create a Style for your TabItems that would add the close button that your class is currently adding?

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