I am binding a collection of images that I retrieve from IsolatedStorage to my View, but I am having issues with changing the order in which images are displayed. There is a timestamp associated with each image, and I would like to be able to sort by either ascending or descending order. As of now the binding works, but when I attempt to change the sort order before binding to my listbox, nothing shows on the UI.
MainPage.xaml
<ListBox x:Name="Recent" ItemsSource="{Binding Pictures}" Margin="8"
SelectionChanged="recent_SelectionChanged" toolkit:TiltEffect.IsTiltEnabled="True"
ItemContainerStyle="{StaticResource MyStyle}">
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<toolkit:WrapPanel Orientation="Horizontal" />
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
</ListBox>
MainPage.xaml.cs
// Constructor
public MainPage()
{
InitializeComponent();
//This is working, but is not sorted
//DataContext = PictureRepository.Instance;
//Attempt at sorting before binding
//from SettingsPage, if AscendingSort = True then sort ascending
if (Settings.AscendingSort.Value)
{
//Give no errors, but does not display on UI
DataContext = PictureRepository.Instance.Pictures.OrderBy(s => s.DateTaken);
}
else
{
DataContext = PictureRepository.Instance.Pictures.OrderByDescending(s => s.DateTaken);
}
}
Not sure exactly what the issue is here?
Note, when debugging, I can see that PictureRepository.Instance contains the images in which to display in the view.
Try this,
listItems = new ObservableCollection<YourType>(listItems.OrderBy(x => x.DateTaken));
Related
while selecting all means renaming all the checkbox are checked. my code is below:
<ListBox Name="VillageList">
<ListBox.ItemTemplate>
<DataTemplate>
<CheckBox IsChecked="{Binding isCheched}" Content="{Binding Villages}" IsChecked="False"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
so all checkbox are inside the listbox.how to checked is enable for all checkbox single selection.
public class villageinformation
{
public string Villages{get;set;}
public bool isChecked {get;set;}
}
page.cs{
list<villageinformation> mydataSource=new list<villageinformation>();
myDataSource.Add(new villageinformation(){Village="All",isChecked ="False"});
myDataSource.Add(new villageinformation(){Village="name1",isChecked ="False"});
myDataSource.Add(new villageinformation(){Village="name2",isChecked ="False"});
myDataSource.Add(new villageinformation(){Village="name3",isChecked ="False"});
VillageList.itemSource=myDataSource;
}
so while clicking manually "All" checkbox remaining name1,2,3 are selected how to do this?
If you are using the ObservableCollection for your villages list, which is used for the data binding to the ListBox, then you can set all values in the ObservalbeCollection in the codebehind which shoul update the UI (by checking all the Checkboxes)
you can do it something like this
foreach(var village in VillagesCollection)
{
village.isChecked = true;
}
If you are not able to understand the above, edit your question with how you are setting up the Village data in the code behind file (means .xaml.cs file)
I'm using MVVM in this project, I have a listbox which bind to a collection of Customers. I want to create an event to navigate a detailsPage using id of the elementselected:
<ListBox ItemsSource="{Binding Customers}" x:Name="state_list" SelectionChanged="state_list_SelectionChanged">
<i:Interaction.Triggers>
<i:EventTrigger EventName="selectionchanged">
<cmd:EventToCommand Command="{Binding stateSelectedCommand}" PassEventArgsToCommand="True" />
</i:EventTrigger>
</i:Interaction.Triggers>
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Vertical">
<TextBlock Text="{Binding nom}" />
<!--TextBlock Text="{Binding LastName}" />
<TextBlock Text="{Binding Text, ElementName=tbCount}" /-->
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
I can't figure out how to get the selected item to add it to the uri and then use it to get data. An example or tutorial would be helpful. Thanks :)
I would create a "SelectedCustomer" property in the ViewModel (next to you Customers property) and bind it to the SelectedItem. Then, on the setter of that property you can navigate to your desired page. This way you eliminate the messy events and command.
<ListBox x:Name="state_list
ItemsSource="{Binding Customers}"
SelectedItem="{Binding SelectedCustomer, Mode=TwoWay}">
...
public Customer SelectedCustomer
{
get
{
return _selectedCustomer;
}
set
{
if (value != null)
{
_selectedCustomer = value;
//Navigate to your page here, either with Navigator class or any other mechanism you have in place for changing content on screen
}
}
}
AlexDrenea gives you a good way of binding SelectedItem to a property on your viewmodel. If you are wanting to navigate based on this in an MVVM architecture, I would suggest using messaging to get it done.
I cover this in a blog post I did a while back, but the short summary of doing this within MVVMLight, is to create a Navigator class that sits at the application level.
public class Navigator
{
private PhoneApplicatoinFrame RootFrame;
public Navigator(PhoneApplicationFrame frame)
{
RootFrame = frame;
RegisterMessages();
}
private void RegisterMessages()
{
Messenger.Default.Register<ShowTrackerMessage>(this, ShowTracker);
}
private void ShowTracker(ShowTrackerMessage msg)
{
RootFrame.Navigate(new Uri("/Views/ItemLocationCompassView.xaml", UriKind.RelativeOrAbsolute));
}
}
Then, as part of your application start-up, create it and pass it a reference to your RootFrame:
private static Navigator _navigator;
public static Navigator Nav
{
get { return _navigator; }
}
...
_navigator = new Navigator(this.RootFrame);
Then, you have a couple choices on how you send the Navigation message.
Option 1: In your ViewModel, hook into the PropertyChanged event (part of INotifyPropertyChanged), and send the appropriate message when your SelectedItem property changes.
Option 2: Tie into the SelectionChanged event of your ListBox. I use the MVVMLight's EventToCommand to send that event to a RelayCommand in my ViewModel, then react appropriately to send the message to the Navigator object.
I cover this in more detail at: http://www.smartchitecture.com/?p=27
I want to databind an ObservableCollection to a Pivot contronl in WP7 so that each object in my ObservableCollection becomes a PivotItem. This is the code I use:
<controls:Pivot x:Name="MainPivot" ItemsSource="{Binding Persons}">
<controls:Pivot.HeaderTemplate>
<DataTemplate>
<TextBlock Text="{Binding FullName}"/>
</DataTemplate>
</controls:Pivot.HeaderTemplate>
<controls:Pivot.ItemTemplate>
<DataTemplate>
<StackPanel Margin="0,0,0,17" Width="432">
<TextBlock Text="{Binding FirstName}"/>
<TextBlock Text="{Binding LastName}"/>
<TextBlock Text="{Binding HomeTown}"/>
</StackPanel>
</DataTemplate>
</controls:Pivot.ItemTemplate>
</controls:Pivot>
This works and with tre items in my ObservableCollection I get three PivotItems. But when everything gets loaded the binding inside the DataTemplate won´t get updated. It is only when I scroll to the next PivotItem that the FirstName, LastName and HomeTown gets loaded.
Why is that? What am I missing?
Thanks
Check this discussion:
DataBound Pivot control is not creating the first PivotItem
I had the same problem, but the workaround with setting SelectedIndex=1 didn't suit me.
I found the other solution: when you adding the Item to your Persons collection you should first create a temp element and only when you fill all data add it to your Persons collection.
Person tempPers = new Person() { FullName = "Abduvaliev Edem", FirstName = "Edem", LastName = "Abduvaliev", HomeTown = "Sevastopol"};
Pesrons.Add(tempPers);
After doing a simple test i cannot reproduce this behavior. I i put a breakpoint inside the get block of the equivalent of FirstName with two items in my ObservableCollection i get two hits.
How did you detect that it is not bound? You cannot see the "next" pivotitems content, so how?
Sounds like there's some problem with the loading order - or with the notification code.
Check that you are correctly firing the PropertyChanged event when you set the properties on each of your FirstName, LastName and HomeTown members.
Here's how I do it. The problem for me is that the collection updates asynchronously in response to a web method call.
void Page_Loaded(object sender, RoutedEventArgs e)
{
_log.Debug("Page loaded.");
var vm = this.GetViewModel<TrendsViewModel>();
if (!vm.IsInitialized)
{
vm.PivotItems.CollectionChanged += (origin, args) =>
{
this.PivotControl.DataContext = null;
this.PivotControl.DataContext = vm;
};
vm.Initialize(this);
}
}
The key is hooking up an observer of the collection to which the Pivot items are bound and giving the data context a shake when it updates.
In the XAML template, I used a listbox to populate some dynamic data.
Now I want to disable touch selection in certain listbox items in Windows Phone 7. How to do that ?
I had done some little research, some people said that the selection event could be prevented in the listbox.
http://social.msdn.microsoft.com/forums/en-US/wpf/thread/8eeed347-ede5-4a24-88f1-953acd16e774
Hope some smart guys could teach me how to solve the problem.
Thanks.
You could use the ItemsControl instead of ListBox. ItemsControl is like ListBox, but it comes without the selection stuff.
<ItemsControl>
<ItemsControl.ItemTemplate>
<DataTemplate>
...
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
Use ItemsControl wrapped in a ScrollViewer. This will give you the same effect without selection (and will allow you to scroll just like a ListBox does)
<ScrollViewer>
<ItemsControl>
<ItemsControl.ItemTemplate>
<DataTemplate>
...
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</ScrollViewer>
Try using a variable to store the last selected index.
If the user then selects an item which you don't want to handle the selection event for then set the selected index back to the stored value. If you do want to hand;e the selection changed event then be sure to update your stored value too.
You'll probably also want to avoid triggering the selection changed when you manually set the index (back).
A simple boolean flag could be used to track this.
Old question but it doesn't look answered. You can do it through code, manipulating the selected item and index, but that's ugly and cumbersome. Instead let's do it declaratively (the XAML way!) with your bound items.
First you'll need a ViewModel with a list of items. Each item needs (at minimum) a property to display and a property to determine if the item is enabled or not.
Here's a sample viewmodel for a single item in the list:
class MyViewModel : ViewModelBase
{
private string _title;
public string Title
{
get { return _title; }
set
{
if(value == _title) return;
_title = value;
RaisePropertyChanged("Title");
}
}
private bool _isEnabled;
public bool IsEnabled
{
get { return _isEnabled; }
set
{
if(value == _isEnabled) return;
_isEnabled = value;
RaisePropertyChanged("IsEnabled");
}
}
}
The above example assumes MVVM Light for the ViewModelBase and the RaisePropertyChanged method, but you can do it with IPropertyNotified yourself (or any other MVVM library).
Next you'll have a listbox with markup similar to the following:
<ListBox ItemsSource="{Binding MyItems}">
<ListBox.ItemContainerStyle>
<Style TargetType="ListBoxItem">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ListBoxItem">
<ContentPresenter IsHitTestVisible="{Binding IsEnabled}"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ListBox.ItemContainerStyle>
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Title}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
That's it. Now just load up some viewmodel with a list of items:
MainViewModel.MyItems = new ObservableCollection<MyViewModel>();
MainViewModel.MyItems.Add(new MyViewModel { Title = "Star Wars", IsEnabled = true });
MainViewModel.MyItems.Add(new MyViewModel { Title = "The Sound of Music", IsEnabled = false });
MainViewModel.MyItems.Add(new MyViewModel { Title = "Aliens", IsEnabled = true });
MainViewModel.MyItems.Add(new MyViewModel { Title = "Debbie Does Dallas", IsEnabled = false });
MainViewModel.MyItems.Add(new MyViewModel { Title = "True Grit", IsEnabled = false });
Only the sci-fi movies in this example are clickable.
Hope that helps.
I'm trying the MVVM Light Toolkit. Though I still think having multiple ViewModels for such small apps is overkill, I like the concepts. What I still can't quite understand is how (or I should say "what is the recommended way") to navigate from one page to another when the selection changes in a ListBox.
The big problem with this toolkit is that it forces you to learn MVVM via other sources before using it, rather than show you what (its vision of) MVVM is from within the framework, accompanying samples and documentation. Are there samples out there showing the different concepts? And please, no videos.
Have you tried modifying your ListBox ItemTemplate to have each item be a HyperlinkButton and just setting the NavigateURI attribute to the Page you want to navigate to?
I still have not figured out how to do this (navigate to a details page upon selection changed in a listbox) without any codebehind in the view. However, if you are OK with having just a little codebehind in the view here's what I recommend:
<ListBox x:Name="MainListBox" Margin="0,0,-12,0" ItemsSource="{Binding Items}"
SelectionChanged="MainListBox_SelectionChanged"
SelectedItem="{Binding Path=SelectedListItem, Mode=TwoWay}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Margin="0,0,0,17" Width="432">
<TextBlock Text="{Binding LineOne}" TextWrapping="Wrap" Style="{StaticResource PhoneTextExtraLargeStyle}"/>
<TextBlock Text="{Binding LineTwo}" TextWrapping="Wrap" Margin="12,-6,12,0" Style="{StaticResource PhoneTextSubtleStyle}"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
First, per above bind to the SelectedItem property of the Listbox with a TwoWay binding to a property in your ViewModel (SelectedListItem in the above).
Then in your codebehind for this page implement the handler for MainListBox_SelectionChanged:
// Handle selection changed on ListBox
private void MainListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
// If selected index is -1 (no selection) do nothing
if (MainListBox.SelectedIndex == -1)
return;
// Navigate to the new page
NavigationService.Navigate(new Uri("/DetailsPage.xaml", UriKind.Relative));
}
This is the only codebehind you need in your main view.
In your main ViewModel you need a SelectedListItem property:
public const string SelectedListItemPropertyName = "SelectedListItem";
private ItemViewModel _SelectedListItem;
/// <summary>
/// Sample ViewModel property; this property is used in the view to display its value using a Binding
/// </summary>
/// <returns></returns>
public ItemViewModel SelectedListItem
{
get
{
return _SelectedListItem;
}
set
{
if (value != _SelectedListItem)
{
_SelectedListItem = value;
RaisePropertyChanged(SelectedListItemPropertyName);
}
}
}
Now, the trick to getting the context passed to your details page (the context being what list item was selected) you need to setup the DataContext in your Details view:
public DetailsPage()
{
InitializeComponent();
if (DataContext == null)
DataContext = App.ViewModel.SelectedListItem;
}
Hope this helps.
eventually you'll want to do more than just navigate, potentially navigate after setting a custom object.
Here is a MVVM-light way of doing this.
You'll first want to bind your listbox selected item to a property in your viewmodel
<ListBox ItemsSource="{Binding Events}" Margin="0,0,-12,0" SelectedItem="{Binding SelectedEvent, Mode=TwoWay}">
Declare your SelectedEvent property
public const string SelectedEventPropertyName = "SelectedEvent";
private Event _selectedEvent;
public Event SelectedEvent
{
get {return _selectedEvent;}
set
{
if (_selectedEvent == value)
{
return;
}
var oldValue = _selectedEvent;
_selectedEvent = value;
// Update bindings and broadcast change using GalaSoft.MvvmLight.Messenging
RaisePropertyChanged(SelectedEventPropertyName, oldValue, value, true);
}
}
You can then define an interaction trigger bound to the tap event
<i:Interaction.Triggers>
<i:EventTrigger EventName="Tap">
<cmd:EventToCommand Command="{Binding EventPageCommand, Mode=OneWay}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
In your viewmodel, define your EventPageCommand as a RelayCommand:
public RelayCommand EventPageCommand { get; private set; }
public MainViewModel()
{
EventPageCommand = new RelayCommand(GoToEventPage);
}
and finally declare your GoToEventPage method
private void GoToEventPage()
{
_navigationService.NavigateTo(new Uri("/EventPage.xaml", UriKind.Relative));
}
note that you can do other actions before navigating to your new page, plus your selected item from your list box is currently set in the property you bound it too.