Develop Reference

WPF -How to access the fields present in a template

Let me explain so I have a wpf application I used a listBox with a template. This template contains a TextBlock and a ComboBox. When running the application, everything goes well, my list is initialized correctly. But then I would like to retrieve the values ​​of my TextBlock and my comboBox and I don't understand how I can achieve this.
I am attaching the part of my XAML code that deals with this listBox :
<ListBox x:Name="ListBoxEnv" Grid.Row="1"
d:ItemsSource="{d:SampleData ItemCount=5}" Width="460"
SelectionChanged="ListBoxEnv_SelectionChanged">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock x:Name="TxtBlockEnv"
VerticalAlignment="Center" HorizontalAlignment="Left"
Text="{Binding EnvName}"/>
<ComboBox x:Name="ComboBoxEnv"
VerticalAlignment="Center" HorizontalAlignment="Left"
ItemsSource="{Binding EnvListValue}"
Margin="100,2,0,2" Width="200"
SelectionChanged="ComboBoxEnv_SelectionChanged"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>

The EnvName property is readonly because it is bound to TextBlock, so you can ignore it. Change binding to: Text="{Binding EnvName, Mode=OneTime}" to save the app resources.
However to extract selected environment in every combo in the list you need to add to ComboBox template: SelectedItem={Binding SelectedEnv} and add new property to SampleData
for example
public MyEnvironmentClass SelectedEnv {get; set;}

Adding custom items to stackpanel

I'm working on a project (for Windows Phone 8 with Visual Studio 2012 with C#) where I want to display some items that each have:
a picture
a title
a description
to be able to be clicked (so that I can navigate to a certain Page)
So I thought I could do that with a stackpanel. But I'm not sure how I can add items that have the above properties and to be able to add those items from XAML. I tired adding items through a ItemsControl in stackpanel but I'm not sure how I can add more complex items like the one I want.

The best approach is to use a ListBox or LongListSelector rather than a StackPanel. You can then:
Data bind the list to the control itself, which will handle adding/deleting items from the control automatically
Define the view for each control using ListBox's ItemTemplate property
First of all, in your code-behind/ViewModel/what-have-you, you'll want to create an ObservableCollection of objects to display. ObservableCollection will let the control know to update in the case an item is added, removed, etc.
public ObservableCollection<T> foo = new ObservableCollection<T>();
In XAML, you'll then want to databind this ObservableCollection to the ListBox you've created:
<ListBox x:Name="ListBox" ItemsSource="{Binding foo}" />
Finally, you can define the ItemTemplate of the ListBox like so:
<ListBox x:Name="ListBox" ItemsSource="{Binding foo}" >
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal" Margin="2">
<TextBlock Text="{Binding Title}" />
<TextBlock Text="{Binding Description}" />
<Image Source="{Binding Image}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
I'd highly recommend reading this guide, especially "Binding a control to a collection of objects" and the section after on DataTemplates. :)

How to customize LongListSelector or ListBox Design in WP8

i like to customize my LongListSelector or ListBox in my own way so can any one help me to design it.. MY Code..
<StackPanel HorizontalAlignment="Left" Height="345" Margin="10,234,0,0" VerticalAlignment="Top" Width="413">
<phone:LongListSelector x:Name="list_organization" Height="340" Margin="10,0"/>
</StackPanel>
This is my code to bind the long list..
org = await client.searchOrganization(txtQuery.Text);
if (org != null)
{
var query = from c in org
select new { c.name,c.id,c.time,.. };
list_organization.ItemsSource = query.ToList();//bind the query to longlist
}
i want like this design page..
how to do it...?

First of all, remove explicit widths and heights. And if you only have a single LongListSelector inside the StackPanel, you can remove the StackPanel.
Individual items for the listbox-like containers is done by using the DataTemplate to replace ItemTemplate. Check the following MSDN link for more information: ListBox Styles and Templates.
Basically, here is how you do it:
<phone:LongListSelector x:Name="list_organization" Height="340" Margin="10,0"
ItemsSource="{Binding People}">
<phone:LongListSelector.ItemTemplate>
<DataTemplate>
<!-- your XAML for individual item goes here -->
<TextBlock Text="{Binding FirstName}" />
</DataTemplate>
</phone:LongListSelector.ItemTemplate>
</phone:LongListSelector>

Controls in Listbox

I'm interesting, can I group some controls (image, 2-3 textboxes) in one element, and then push group of this elements in listbox? I'm trying to make a news reader of russian social network Vkontakte into Windwos Phone 7.
Each news has an image, text, and some other metadata. So I want to group all this info in one control and use it in listbox.
I tryied to push a grid(which had an image and two textboxes) into listbox, but it throws XamlParseException.
Also, I need to get the content of theese textboxes and images from code. In grid I can use
<Grid.Resources>
<src:Customers x:Key="customers"/>
</Grid.Resources>

Here is what you need:
A collection (ObservableCollection<T> recommended) of models (News in you case).
A ListBox
A DataTemplate
Example:
XAML:
<ListBox Name="ListBox1">
<ListBox.ItemTemplate>
<DataTemplate>
<Grid>
...
<Image Source="{Binding ImagePropertyInModel}" ... />
<TextBlock Text="{Binding TextPropertyInModel}" ... />
...
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
Code behind:
ListBox1.ItemsSource = <collection of models>;
Instead of the <Grid> in <DataTemplate> you can use a Custom Control (Templated Control) or a User Control that you may already have.

You can create an UserControl with the controls you want to use. With your ListBox you do something like:
<ListBox ItemsSource="{Binding Path=YourItemsSource}">
<ListBox.ItemTemplate>
<DataTemplate>
<my:MyUserControl DataContext="{Binding}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
As ItemsSource of your ListBox you could use a ObservableCollection of News and through DataContext="{Binding}" you can bind to the News properties in your UserControl, e.g.:
<UserControl...>
<Image Source="{Binding Path=photoAttachment}"/>
</UserControl>

Modifying an individual TreeViewItem on a databound WPF TreeView without modifying the data source

I've got a MVVM WPF app with the TreeView databound to a viewmodel class. It is essentially a file explorer. I want to add the ability to "Add a new folder" to the hierarchy. To achieve the desired functionality what I am trying to do is simply switch the Textblock out for an editable TextBox in my datatemplate. This is what my datatemplate looks like:
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Children}">
<StackPanel Name="tv_itempanel"
Orientation="Horizontal"
Margin="2">
<Image Source="{Binding Icon}" Margin="4"/>
<TextBlock Name="treeitem_tblock" Margin="4" Text="{Binding Name}"/>
<TextBox Width="200" Visibility="Collapsed" Name="treeitem_tbox"/>
</StackPanel>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
The problem is that I cannot modify an individual TreeViewItem since the treeview is databound. Any ideas? Thanks

Add a bool IsEditable property to your VM objects, and bind the visibility of the TextBox to is (using a converter to transform the boolean value to a Visibility enum). That way you don't need to manipulate the TreeViewItem directly, simply mark the data object as editable, and it will flow naturally to your view.