Acces to a button in a DataTemplate

Sat, 28 Oct 2006 11:10:26 Z

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>

<Setter.Value>

</Border>

<ControlTemplate.Triggers>

</Trigger>

</Trigger>

</ControlTemplate.Triggers>

</ControlTemplate>

</Setter.Value>

</Setter>

</Style>

</StackPanel>

</Button>

</DataTemplate>

<Grid>

<Grid.ColumnDefinitions>

</Grid.ColumnDefinitions>

<Grid.RowDefinitions>

</Grid.RowDefinitions>

<Presence:Persona Name="UserPresence" />

</WindowsFormsHost>

</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

Acces to a button in a DataTemplate

Sat, 28 Oct 2006 12:05:10 Z

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

Acces to a button in a DataTemplate

Sat, 28 Oct 2006 12:22:43 Z

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;

Acces to a button in a DataTemplate

Sat, 28 Oct 2006 12:51:43 Z

Zhou Yong wrote:

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;

But still with the error:

This operation is valid only on elements that have this template applied.

Any ideas ?

Thanks !

Thomas

Acces to a button in a DataTemplate

Sat, 28 Oct 2006 14:15:08 Z

OK, I've solved my problem using the LoadContent method of the DataTemplate:

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

Button btn = Template.LoadContent() as Button;

Grid grid = btn.Content as Grid;

WindowsFormsHost host = grid.Children[1] as WindowsFormsHost;

Persona UserPresence = host.Child as Persona;

UserPresence.SipUri = node.Item.Email.ToLower();

HTH

Bye

Acces to a button in a DataTemplate

Sat, 28 Oct 2006 14:16:33 Z

Are you sure the contentPresenter you return is of ContentPresenter or is of ContentPresenter derivatives? or are you sure it's not null?

Sheva

Acces to a button in a DataTemplate

Sat, 28 Oct 2006 15:01:27 Z

Yes, the GraphContentPresenter class inherit from ContentPresenter.