We Keep Coding

Bind a property, inside DataTemplateItem in ListBox, to an outside object in MainPage

I got ListBox with DataTemplate, inside DataTemplate I got another ListBox, trying to bind it's Visibility to another object which is found in the MainPage
XAML:
<ListBox x:Name="RegistersListView" ItemsSource="{x:Bind registersList}">
<ListBox.ItemTemplate>
<DataTemplate x:DataType="structures:Register">
<StackPanel>
<ListBox x:Name="FieldsListView" ItemsSource="{x:Bind fields_list}" Visibility="{x:Bind SomeVisibilityObjectIMain}">
<ListBox.ItemTemplate>
<DataTemplate x:DataType="structures:Field">
<Button Content="{x:Bind name}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
C#:
public sealed partial class HWTab : Page
{
public ObservableCollection<Register> registersList = new ObservableCollection<Register>();
public var SomeVisibilityObjectIMain;
public HWTab()
{
InitializeComponent();
InitData();
this.DataContext = hwType;
}
....
}
I need to bind to "SomeVisibilityObjectIMain" somehow, I tried to bind with ElementName or even make object static, but could not succeed.
My bindable object is more complex than the example here but solve this will give me the way for solution.

You could use {Binding} instead of x:Bind. This way you could add a x:Name="Page" to your page and then use this name in the inner binding:
{Binding ElementName=Page, Path=MyProperty}
For {Binding} to work however, MyProperty must be actually a property. From your sample code (which uses var which is also invalid) it seems it is just a plain field, so you will need something like:
public string MyProperty {get;set;}
To also get PropertyChanged notifications, you will need to add a backing field and trigger PropertyChanged event.
However, overall a better solution would be to include all information a DataTemplate needs into the actual items which are bound to it. That means - you would create a custom view model type for the items, which would include the information that you need to control visibility.

Get Listboxitem from listbox

Hi this should be faily simple, however I don't know what I am doing wrong. I've been looking all over the internet seeing people make this work, even followed the tutorial on MSDN still nothing has worked for me.
I want to Iterate over a ListBox, and get the ListBoxItems so I can find the DataTemplate that I have added to it.
This is my code behind.
private void SetListBoxDataTemplate(ListBox MyListBox)
{
try
{
foreach (CustomDataTemplateObject dataobject in MyListBox.Items)
{
ListBoxItem lbi = (ListBoxItem)(MyListBox.ItemContainerGenerator.ContainerFromItem(dataobject));
ContentPresenter myContentPresenter = FindVisualChild<ContentPresenter>(lbi);
DataTemplate dt = myContentPresenter.ContentTemplate;
TextBlock tb = (TextBlock)dt.FindName("ListBoxItemTextBlock1", myContentPresenter);
ComboBox cb = (ComboBox)dt.FindName("ListBoxItemComboBox1", myContentPresenter);
tb.Text = dataobject.Text;
cb.ItemsSource = dataobject.ListColors;
}
}
catch (Exception ex)
{
MessageBox.Show(""+ex);
}
}
XAML looks like this:
<DataTemplate x:Key="ListBoxItemDataTemplate1">
<StackPanel Orientation="Horizontal">
<Border BorderBrush="Black" BorderThickness="1 1 0 1" MinWidth="50">
<TextBlock Name="ListBoxItemTextBlock1" Background="{Binding ElementName=ListBoxItemComboBox1, Path=SelectedValue}" >
</TextBlock>
</Border>
<ComboBox Name="ListBoxItemComboBox1" />
</StackPanel>
</DataTemplate>*
<StackPanel>
<ListBox Name="ListBoxTest1" ItemTemplate="{DynamicResource ListBoxItemDataTemplate1}" />
</StackPanel>
I have tried with setting my itemtemplate to static to see if it works, and the method i'm calling from code behind, is called after I have populated my ListBoxs
My dataobject is NOT null, however when i call the line in my code behind, my lbi, ends up being null.
Any suggestions? thanks in advance!
FIRST UPDATE
This problem only occurs if i call the method in my constructor, so perhaps it's because it hasn't initialized the full group element section yet. However I want to do this as soon as possible. Am I perhaps forced to do it in a WindowLoaded event?
SECOND UPDATE
Code updated, Rachel's answer worked for iterating over my ListBoxItems, however the Listbox Has not fully rendered since i'm unable to reach the Datatemplate at this time. So MyListBox_GeneratorStatusChanged is not working for this problem, but it does get the ListBoxItems.

WPF's main thread runs items at different priority levels. Code that runs in the Constructor all gets run at Normal priority, while things like rendering the ListBox and it's items run at the Render priority level, which occurs after all Normal priority operations have finished.
This means that your entire Constructor gets run (including SetListBoxDataTemplate()) before your ListBox is even rendered and the items get generated.
If you want to run some code after the items are generated, use the ItemsContainerGenerator.StatusChanged event
// Constructor
MyListBox.ItemContainerGenerator.StatusChanged += MyListBox_GeneratorStatusChanged;
...
void MyListBox_GeneratorStatusChanged(object sender, EventArgs e)
{
// return if containers have not been generated yet
if (MyListBox.ItemContainerGenerator.Status != GeneratorStatus.ContainersGenerated)
return;
// remove event
MyListBox.ItemContainerGenerator.StatusChanged -= MyListBox_GeneratorStatusChanged;
// your items are now generated
SetListBoxDataTemplate(MyListBox);
}
What are you trying to accomplish with this method anyways? It is a bit unusual for WPF, and there may be a much better WPF way of accomplishing your task.
Updated based on new code added to Question
A much better method of setting your Text and ItemsSource properties is to make use of WPF's data bindings.
Your DataTemplate should look like this:
<DataTemplate x:Key="ListBoxItemDataTemplate1">
<StackPanel Orientation="Horizontal">
<Border BorderBrush="Black" BorderThickness="1 1 0 1" MinWidth="50">
<TextBlock Text="{Binding Text}" Background="{Binding ElementName=ListBoxItemComboBox1, Path=SelectedValue}" >
</TextBlock>
</Border>
<ComboBox ItemsSource="{Binding ListColors}" />
</StackPanel>
</DataTemplate>*
A DataTemplate is like a cookie cutter. It's used to make the UI objects, but is not part of the UI object itself. All it does is tell WPF that "When you go to render this object, render it using this XAML". So the way your XAML gets rendered is
<ListBoxItem>
<StackPanel>
<Border>
<TextBlock Text="{Binding Text}" />
</Border>
<ComboBox ItemsSource="{Binding ListColors}">
</StackPanel>
</ListBoxItem>
In addition, the DataContext behind your ListBoxItem is the item from the collection bound to ListBox.ItemsSource, which based on your code should be CustomDataTemplateObject. That allows the bindings from the DataTemplate to work
If you're new to WPF and struggling to understand how exact the DataContext works, I'd recommend reading this article of mine: What is this "DataContext" you speak of?.
To summarize, WPF has two layers to an application: the UI layer and the Data Layer (DataContext). When you perform a basic binding like above, you are pulling data from the data layer into the UI layer.
So your ListBoxItem has a data layer of CustomDataTemplateObject, and the TextBlock.Text and ComboBox.ItemsSource bindings are pulling data from the data layer for use in the UI layer.
I'd also highly recommend using a utility like Snoop which lets you view the entire Visual Tree of a running WPF application to see how items get rendered. Its very useful for debugging or learning more about how WPF works.

You're confusing two jobs and mixing them into one. First, get access to the ListBoxItem:
private void SetListBoxDataTemplate(ListBox MyListBox)
{
foreach (ListBoxItem listBoxItem in MyListBox.Items)
{
}
}
Now you can get the DataTemplate from the ListBoxItem:
foreach (ListBoxItem listBoxItem in MyListBox.Items)
{
ContentPresenter presenter = FindVisualChild<ContentPresenter>(listBoxItem);
DataTemplate dataTemplate = presenter.ContentTemplate;
if (dataTemplate != null)
{
// Do something with dataTemplate here
}
}
The FindVisualChild method can be found in the How to: Find DataTemplate-Generated Elements page on MSDN.
UPDATE >>>
To answer your edit, yes, the constructor will be too early to try to access these DataTemplates because the Framework won't have applied them to all of the objects by then. It is best to use the FrameworkElement.Loaded Event to do these kinds of things, as that is the first event that can be called after the controls have all been initialised.

WPF/C# Binding custom object list data to a ListBox?

I've ran into a bit of a wall with being able to bind data of my custom object list to a ListBox in WPF.
This is the custom object:
public class FileItem
{
public string Name { get; set; }
public string Path { get; set; }
}
And this is the list:
private List<FileItem> folder = new List<FileItem>();
public List<FileItem> Folder { get { return folder; } }
The list gets populated and maintained by a FileSystemWatcher as files get moved around, deleted, renamed, etc. All the list does is keeps tracks of names and paths.
Here's what I have in the MainWindow code-behind file (it's hard coded for testing purposes for now):
FolderWatcher folder1 = new FolderWatcher();
folder1.Run(#"E:\MyApp\test", "*.txt");
listboxFolder1.ItemsSource = folder1.Folder;
Here's my XAML portion:
<ListBox x:Name="listboxFolder1" Grid.Row="1" BorderThickness="0"
ItemsSource="{Binding}"/>
Unfortunately, the only thing that gets displayed is MyApp.FileItem for every entry. How do I display the specific property such as name?

You will need to define the ItemTemplate for your ListBox
<ListBox x:Name="listboxFolder1" Grid.Row="1" BorderThickness="0"
ItemsSource="{Binding}">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Name}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>

The easiest way is to override ToString on your FileItem, (The listbox uses this to populate each entry)
public override string ToString()
{
return Name;
}

Each item in the list that ListBox shows automatically calls the ToString method to display it, and since you didn't override it, it displays the name of the type.
So, there are two things you can do here.
Override the ToString method like Sayse suggested.
Use DataTemplate and bind each of your properties seperatly
In your resource add the template with a key
<DataTemplate x:Key="fileItemTemplate">
<StackPanel>
<TextBlock Text="{Binding Name}"/>
<TextBlock Text="{Binding Path}"/>
</StackPanel>
</DataTemplate>
and give it as your listbox ItemTemplate
<ListBox x:Name="listboxFolder1" Grid.Row="1" BorderThickness="0" ItemsSource="{Binding}" ItemTemplate="{StaticResource fileItemTemplate}">

In case anyone comes across this now via search, I just encountered pretty much the same issue in a C# UWP app.
While the XAML bits in Nitin's answer above were necessary, they didn't fix the issue alone -- I also had to change my equivalent of Folder to be an ObservableCollection, rather than a List, to get the ListBox to show the property I needed.

Use of DataTemplate

I'm quite new to C# and Windows Phone 7 for that sake, but none the less, I've thrown myself into trying to make a small app for myself. Here's my problem:
I'm trying to set up a DataTemplate that will position my Name and Drinks variables that I've declared in MainPage.xaml.cs. Here's my action when button1 is clicked:
private void button1_Click(object sender, RoutedEventArgs e)
{
string Name = participantName.Text;
int Drinks = 0;
listBox1.Items.Add(Name + Drinks);
}
And here is my DataTemplate from MainPage.xaml
<ListBox Height="Auto" HorizontalAlignment="Stretch" Margin="7,74,0,0" Name="listBox1" VerticalAlignment="Stretch" Width="Auto">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal" Height="132">
<TextBlock Text="{Binding Path=Name}" FontSize="35" />
<StackPanel Width="370">
<TextBlock Text="{Binding Path=Drinks}" FontSize="35" />
</StackPanel>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
The problem is that my data is not shown. It works perfectly without the DataTemplate, but as soon as I use it, my text simply doesn't get through. Your help is very much appreciated.

The template itself is ok. The bindings on the template, though, are currently incorrect.
When you add a new item to the list box, you are just adding a plain old string (which is currently missing a space, BTW.) Your bindings, though, expect the object in the list to have a Name property and a Drinks property, which of course the string class does not have.
The usual solution here is to logically separate your data model from your presentation, by creating a class to store the data itself (probably PersonDrink, with the appropriate Name and Drinks properties) and then adding those objects to the list.
You should read up on the MVVM pattern, as it provides an excellent way to ensure that changes in your data are reflected in your view, and visa versa.

http://amarchandra.wordpress.com/2011/12/18/binding-multiple-object-in-wp7-using-listbox/
Here is a sample for binding data using a datatemplate. I hope this might help you.

DataSource reflected after maximizing the window in wpf

This is really peculiar. I tried a simple data binding example program. I tried to bind a collection (IList) to a list box. When i alter the collection, the list box is updated only if i maximize the window. Here are the snippets,
<ListBox x:Name="myBirthdaysListBox" ItemsSource="{Binding}">
<ListBox.ItemTemplate>
<DataTemplate>
<UniformGrid>
<Label Content="{Binding Name}"></Label>
<Label Content="{Binding DateOfBirth}"></Label>
</UniformGrid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
public Window1()
{
InitializeComponent();
myCalendar = new List<Calendar>();
myBirthdaysListBox.DataContext = myCalendar;
}
I am just a beginner in wpf. Kindly let me know, if i have done some thing terribly wrong in here.

Try using a BindingList<Calendar> rather than just a List<Calendar>, As binding list raises events for when items get added/removed/etc.
What you're seeing is the control is redrawing when you resize, and it's going through all the data again.
Off the top of my head, I believe you need to implement INotifyPropertyChanged on your Calendar such that the binding list is notified if an item in it changes