Acces to a button in a DataTemplate

Question

Hello everybody,

 

In my application, I've got this XAML code:

<Page.Resources>

<SharepointListItemsViewer:NodeTemplateSelector x:Key="nodeTemplateSelector" />

</Page.Resources>

 

<Graph:Graph Name="theGraph" NodesBindingPath="ChildNodes"

CoefficientOfDampening="0.7"

FrameRate="0.5"

NodeTemplateSelector="{StaticResource nodeTemplateSelector}">

<Graph:Graph.Resources>

<Style TargetType="{x:Type Button}">

<Setter Property="Template">

<Setter.Value>

<ControlTemplate TargetType="{x:Type Button}">

<Border Name="theBorder" BorderBrush="Gray" BorderThickness="2" CornerRadius="10" Padding="5" Background="{TemplateBinding Background}">

<ContentPresenter/>

</Border>

<ControlTemplate.Triggers>

<Trigger Property="IsMouseOver" Value="True">

<Setter TargetName="theBorder" Property="BorderBrush" Value="#333333"/>

</Trigger>

<Trigger Property="IsPressed" Value="True">

<Setter TargetName="theBorder" Property="Background" Value="#CCCCCC"/>

</Trigger>

</ControlTemplate.Triggers>

</ControlTemplate>

</Setter.Value>

</Setter>

</Style>

<DataTemplate x:Key="nodeTemplate">

<Button Background="BurlyWood" CommandParameter="{Binding }" Click="DisplayDetails" Name="btnodeTemplate">

<StackPanel Orientation="Vertical">

<Image Source="{Binding Path=Item.ImageUrl, Mode=OneWay, Converter={StaticResource ImageConverter}}" Name="ItemDisplayedImage" Width="50" Height="50" HorizontalAlignment="Center" />

<TextBlock Text="{Binding Path=Item.Name}" FontSize="11" HorizontalAlignment="Center" />

</StackPanel>

</Button>

</DataTemplate>

<DataTemplate x:Key="PersonTemplate">

<Button Background="BurlyWood" CommandParameter="{Binding }" Click="DisplayDetails" Name="btPersonTemplate">

<Grid>

<Grid.ColumnDefinitions>

<ColumnDefinition />

<ColumnDefinition />

</Grid.ColumnDefinitions>

<Grid.RowDefinitions>

<RowDefinition Height="0.1*" />

<RowDefinition Height="0.9*" />

</Grid.RowDefinitions>

<Image Source="{Binding Path=Item.ImageUrl, Mode=OneWay, Converter={StaticResource ImageConverter}}" Name="ItemDisplayedImage" Width="50" Height="50" HorizontalAlignment="Center" Grid.Row="0" Grid.ColumnSpan="2" />

<WindowsFormsHost Name="HostPresenceControl" Grid.Row="1" Grid.Column="0" Margin="0,0,5,0">

<Presence:Persona Name="UserPresence" />

</WindowsFormsHost>

<TextBlock Text="{Binding Path=Item.Name}" Grid.Row="1" Grid.Column="1" FontSize="11" HorizontalAlignment="Center" />

</Grid>

</Button>

</DataTemplate>

</Graph:Graph.Resources>

</Graph:Graph>

And here is the DataTemplateSelector class associated to this XAML code:

internal class NodeTemplateSelector : DataTemplateSelector

{

public override DataTemplate SelectTemplate(object item, DependencyObject container)

{

Node<Item> node = item as Node<Item>;

if (node != null)

{

// Select the correct NodeTemplate according to the type of the item

if (node.Item.Type == ItemType.Person)

{

DataTemplate Template = ((FrameworkElement)container).FindResource("PersonTemplate") as DataTemplate;

Button btn = Template.FindName("btPersonTemplate", ???) as Button;

return (DataTemplate)((FrameworkElement)container).FindResource("PersonTemplate");

}

else

{

return (DataTemplate)((FrameworkElement)container).FindResource("nodeTemplate");

}

}

return null;

}

}

I want to ba able to access to the Button which is in my DataTemplate to do some binding on the WindowsFormsHost's Child (accessible using VisualTreeHelper class).

But I don't know what I need to use here as a second parameter of the FindName mehod:

Button btn = Template.FindName("btPersonTemplate", ???) as Button;

 

Anyone have an idea ? Or maybe another/better idea ?

 

 

Thanks !

 

Thomas

Answer 1

Well, FindName method expects a valid parent which the template is applied, the tricky part is that there is no MSDN documentation on who's the valid templated parent for data template, actually the valid templated parent for DataTemplate is ContentPresenter, so in your original xaml, you should first grab a  reference to the  ContentPresenter inside the control template, then pass that reference to the Template.FindName() method as the second parameter.

Sheva

Answer 2

I've tri te following but I'm still having an error on the FindName method:

 

Graph graph = (Graph)VisualTreeHelper.GetParent(((FrameworkElement)container));

DataTemplate Template = graph.Resources["PersonTemplate"] as DataTemplate;

Button btn = Template.FindName("btPersonTemplate", graph) as Button;

 

 

:(

Answer 3

Zhou Yong wrote:

Well, FindName method expects a valid parent which the template is applied, the tricky part is that there is no MSDN documentation on who's the valid templated parent for data template, actually the valid templated parent for DataTemplate is ContentPresenter, so in your original xaml, you should first grab a  reference to the  ContentPresenter inside the control template, then pass that reference to the Template.FindName() method as the second parameter. Sheva

 

Based on your idea, I've triied the following:

Graph graph = (Graph)VisualTreeHelper.GetParent(((FrameworkElement)container));

Graph.GraphContentPresenter contentPresenter = (Graph.GraphContentPresenter)VisualTreeHelper.GetChild(graph, 0);

DataTemplate Template = graph.Resources["PersonTemplate"] as DataTemplate;

Button btn = Template.FindName("btPersonTemplate", contentPresenter) as Button;