Develop Reference

Can't change ComboBox selection when bound to ObservableCollection (WPF)

I'm trying to create an edit form for editing properties of a custom set of TV Series objects. One of the properties holds a collection of all owned media formats (DVD, Blu-ray, etc) for that particular series that will be displayed in a ComboBox. Items are added to the ComboBox via a separate popup window and items are to be removed from the ComboBox by selecting the item and clicking a remove Button.
I can add new entries to the MediaOwned ComboBox just fine, but when I try to select a specific ComboBox item to test the remove Button I find that I can only ever select the first entry. Can someone please tell me if I've missed something embarrassingly obvious, thanks.
Here is the problematic property:
private ObservableCollection<string> _mediaOwned = new ObservableCollection<string>();
public ObservableCollection<string> MediaOwned
{
get { return _mediaOwned; }
set
{
_mediaOwned = value;
OnPropertyChanged(new PropertyChangedEventArgs("MediaOwned"));
}
}
Here are the other relevant code behind:
private void Window_Loaded(object sender, RoutedEventArgs e)
{
// Create binding for the ListBox.
Binding listBinding = new Binding();
listBinding.Source = show.Series;
listBinding.Mode = BindingMode.OneWay;
listBinding.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged;
lbSeries.SetBinding(ListBox.ItemsSourceProperty, listBinding);
// Create binding for the ComboBox.
Binding myBinding = new Binding();
myBinding.Path = new PropertyPath("MediaOwned");
myBinding.Mode = BindingMode.TwoWay;
myBinding.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged;
cbMediaOwned.SetBinding(ComboBox.ItemsSourceProperty, myBinding);
}
private void btnRemoveMedia_Click(object sender, RoutedEventArgs e)
{
Series series = (Series)lbSeries.SelectedItem;
series.MediaOwned.Remove(cbMediaOwned.Text);
}
And here is the XAML code:
<Border Style="{StaticResource PanelBorderStyle}" DockPanel.Dock="Left" Margin="0,8,8,0"
DataContext="{Binding ElementName=lbLists, Path=SelectedItem}">
<DockPanel VerticalAlignment="Top">
<StackPanel>
<ListBox x:Name="lbSeries" Style="{StaticResource BasicListStyle}" Width="180" Height="300"
DisplayMemberPath="Title" SelectionMode="Single" LayoutUpdated="lbSeries_LayoutUpdated">
</ListBox>
</StackPanel>
<StackPanel x:Name="editPanel" DataContext="{Binding ElementName=lbSeries, Path=SelectedItem}">
<StackPanel Orientation="Horizontal" HorizontalAlignment="Left" VerticalAlignment="Top" Margin="0, 4, 0, 0">
<TextBlock Style="{StaticResource SmallFont}" Width="100">Title</TextBlock>
<TextBox x:Name="txtTitle" Style="{StaticResource TextBoxStyle}" Text="{Binding Path=Title, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" Width="200" Margin="8, 8, 16, 8"></TextBox>
</StackPanel>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Left" VerticalAlignment="Top">
<TextBlock Style="{StaticResource SmallFont}" Width="100">Media owned</TextBlock>
<ComboBox x:Name="cbMediaOwned" Style="{StaticResource ComboBoxStyle}" Width="150" Margin="8,8,6,8"
></ComboBox>
<Button x:Name="btnAddMedia" Style="{StaticResource ToolbarButtonStyle}" Click="btnAddMedia_Click" Margin="0">
<StackPanel ToolTip="Add media">
<Image Source="Images/add.png" />
</StackPanel>
</Button>
<Button x:Name="btnRemoveMedia" Style="{StaticResource ToolbarButtonStyle}" Click="btnRemoveMedia_Click" Margin="4">
<StackPanel ToolTip="Remove media">
<Image Source="Images/remove.png" />
</StackPanel>
</Button>
</StackPanel>
</StackPanel>
</DockPanel>
</Border>
Alternatively I can also remove the binding code in the code behind and replace the ComboBox with the below code (but I still get the same problem - I can't select anything in the ComboBox):
<ComboBox x:Name="cbMediaOwned" Style="{StaticResource ComboBoxStyle}" Width="150" Margin="8,8,6,8" ItemsSource="{Binding ElementName=lbSeries, Path=SelectedItem.MediaOwned, UpdateSourceTrigger=PropertyChanged}"
SelectedItem="{Binding SelectedMedia, UpdateSourceTrigger=PropertyChanged}"></ComboBox>
SelectedMedia property:
private string _selectedMedia = "";
public string SelectedMedia
{
get { return _selectedMedia; }
set
{
_selectedMedia = value;
OnPropertyChanged(new PropertyChangedEventArgs("SelectedMedia"));
}
}

Here is my xaml:
<ComboBox x:Name="Models_ComboBox"
Width="110"
Text="Model"
ItemsSource="{Binding Models}"
SelectedItem="{Binding SelectedModel}"
DisplayMemberPath="Model"
MouseDoubleClick="Models_ComboBox_MouseDoubleClick"
SelectionChanged="Models_ComboBox_SelectionChanged"/>
Here are my VM properties:
private DataTable models;
public DataTable Models
{
get { return models; }
set
{
if (models != value)
{
models = value;
OnPropertyChanged(nameof(Models));
}
}
}
and
private DataRowView selectedModel;
public DataRowView SelectedModel
{
get { return selectedModel; }
set
{
if (selectedModel != value)
{
selectedModel = value;
if (value != null)
{
InitializeOptions(value["Model"].ToString());
}
OnPropertyChanged(nameof(SelectedModel));
}
}
}
As you can see, the ItemsSource and the SelectedItem of the ComboBox are bound to two different properties in the ViewModel. The ItemsSource is bound to a DataTable populated from a Database. Once the user selects a Model, then there are other option ComboBoxes that are populated based on that selection.

Fixed the problem myself. I had a line of code that was automatically setting the SelectedIndex of the ComboBox without me realizing.

UWP update a itemscontrol with an array that keeps updating

I have an array that keeps changing its values, because of this I want to have the apps UI refreshing every time the array's values do. I have this bound with an itemsControl. I can show the first array's values but then I can't update them I have tried .items.Clear() but its not working. Here are snippets of the .xaml and the xaml.cs. I actually took the code of the .xaml from a question from this site.
.xaml
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
<TextBox Text="Testing" IsReadOnly="True"></TextBox>
<ItemsControl x:Name="itemsControl"
ItemsSource="{Binding itemsControl}"
FontSize="24">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Grid Width="Auto"
Margin="0 12"
HorizontalAlignment="Center">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<StackPanel Grid.Column="0"
Grid.Row="0"
Orientation="Horizontal">
<TextBlock Name="txtblk0" Text="{Binding}" />
</StackPanel>
</Grid>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
.xaml.cs
String c = (new String(cArray));
string[] arr = null;
string[] data = null;
if (c != null)
{
arr = c.Split('\n');
if (arr.Length > 0)
{
data = arr[0].Split(',');
}
}
for(int index = 0; index < 4; index++)
{
itemsControl.Items.Add(float.Parse(data[index]));
}
itemsControl.Clear();
If anyone has an idea of how I can do this I will be very grateful, thanks in advance and I will try to answer any questions as soon as possible!

What you're missing is an understanding of how bindings are triggered to update.
The INotifyPropertyChanged interface contains a method (PropertyChanged) and when called and passed the name of a property will tell the binding system that the property has changed and the binding should be updated.
INotifyCollectionChanged is the equivalent for collections, and communicates when a collection has changed. i.e. something added, removed, or the list cleared.
ObservableCollection<T> contains an implementation of INotifyCollectionChanged that makes it easy to work with lists, collections, etc. that change.
If you used an ObservableCollection<float> instead of an array you'd be able to modify the list and have the UI updated to reflect this easily.
As a starter, see the following which demonstrates how easy it is to use an ObservableCollection.
XAML:
<StackPanel>
<Button Click="Button_Click">add an item</Button>
<ItemsControl ItemsSource="{Binding Items}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding}" />
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</StackPanel>
code behind;
public MainPage()
{
this.InitializeComponent();
// Initialize the property
this.Items = new ObservableCollection<string>();
// Use self as datacontext (but would normally use a separate viewmodel)
this.DataContext = this;
}
private void Button_Click(object sender, RoutedEventArgs e)
{
// add a new item to the UI
this.Items.Add(DateTime.Now.ToString());
}
// The "collection" that is shown in the UI
public ObservableCollection<string> Items { get; set; }

Windows phone app change color of pivot page items even odd

I have built Windows phone app now I want to change pivot page items color on the base of even odd items.
How it is possible? any solution will be appreciated.
Here is some code example:
<PivotItem
x:Uid="PivotItem1"
Margin="19,152,0,-29.5"
Header="Inbox"
CommonNavigationTransitionInfo.IsStaggerElement="True">
<ListView x:Name="myInbox"
IsItemClickEnabled="True"
ItemClick="ItemView_ItemClick"
ContinuumNavigationTransitionInfo.ExitElementContainer="True" FontSize="36" Margin="-18,-139,-0.167,55.333">
<ListView.ItemTemplate>
<DataTemplate>
<Grid >
<Grid.ColumnDefinitions>
<ColumnDefinition Width="4*"/>
<ColumnDefinition Width="1*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition MinHeight="30" />
</Grid.RowDefinitions>
<TextBlock Grid.Column="0" TextWrapping="NoWrap" Text="{Binding Subject}" FontSize="22" Grid.Row="0"></TextBlock>
<TextBlock Grid.Column="1" TextAlignment="Right" TextWrapping="NoWrap" Text="{Binding Date}" Grid.Row="0"></TextBlock>
</Grid>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</PivotItem>
I want to change color of item in code behind.
public sealed partial class PivotPage : Page
{
void PageLoaded(object sender, RoutedEventArgs e)
{
if (User.isLogedIn == false)
{
this.Frame.Navigate(typeof(Login));
}
else
{
LoadInbox(myInbox);
}
}
public async void LoadInbox(ListView list)
{
list.ItemsSource = EmailManager.EmailInbox;
}
}
Email manager email inbox code
class EmailManager
{
public static List<EmailMessage> EmailInbox;
public EmailManager(){
EmaiInbox.Add(new EmailMessage { Id = 1, Subject = "my email subject one with long long text header", Date = "12-Dec-2015 05:10", Contents = "Following the comments on the question, one possible answer would be to suscribe to the Loaded event of your page and call the Event method from there.", Sender = "abc#example.com" });
EmaiInbox.Add(new EmailMessage { Id = 2, Subject = "my email subject 2", Date = "12-Dec-2015 07:25", Contents = "Following the comments on the question, one possible answer would be to suscribe to the Loaded event of your page and call the Event method from there.", Sender = "abc#example.com" });
}
}

Okay I got solution, want to share.
if you want to change Foreground color of a list this simply use this:
yourlist.Foreground = new SolidColorBrush(Colors.Red);
in mine code:
else
{
LoadInbox(myInbox);
/// myInbox.Background = new SolidColorBrush(Colors.Red);
myInbox.Foreground = new SolidColorBrush(Colors.Red);
myOutbox.Foreground = new SolidColorBrush(Colors.Red);
}
Also you can change color of grid child item like this way:
public YourConstructor() // replace YourConstructor with your class name.
{
this.InitializeComponent();
this.navigationHelper = new NavigationHelper(this);
this.navigationHelper.LoadState += this.NavigationHelper_LoadState;
this.navigationHelper.SaveState += this.NavigationHelper_SaveState;
foreach (var c in ContentRoot.Children)
{
if (c.GetType() == typeof(TextBlock))
{
var c1 = c as TextBlock;
c1.Foreground = new SolidColorBrush(Colors.Red);
}
}
}
ContentRoot is grid of page.

get checked items of listview using checkbox windows store app c#

I am developing one Windows store application. I have implemented one listview. listview contains image , textblock and checkbox controls. my listview gets the data from internet i have done xml parsing with listview and binded data to listview. i want to get all the data from listview where checkboxes are checked in listview.
my xaml code is:
<ListView Name="display" ItemsSource="{Binding}" SelectionMode="Single"
SelectionChanged="display_SelectionChanged"
ScrollViewer.HorizontalScrollMode="Enabled" ScrollViewer.HorizontalScrollBarVisibility="Visible"
ItemContainerStyle="{StaticResource ListViewItemStyle12}" >
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel x:Name="stak2" Orientation="Horizontal" />
</ItemsPanelTemplate>
</ListView.ItemsPanel>
<ListView.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Vertical">
<Image Source="{Binding Path=Image}" Width="450" Tapped="image_taped" />
<CheckBox Tag="{Binding Path=tag}" Visibility="{Binding Path=visichk}" Height="40" Name="addremove"
HorizontalAlignment="Center" Checked="add_checked" Unchecked="sub_checked" Opacity="0.5"
Background="White" VerticalAlignment="Top" Template="{StaticResource CheckboxImageTemplate}" >
</CheckBox>
<TextBlock Text="{Binding Image_code}" FontSize="25" Foreground="Gray" HorizontalAlignment="Center" />
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
datasource for listview :
XDocument xmlDoc = XDocument.Parse(responseString);
var Categories = xmlDoc.Descendants("product").ToArray();
List<ProductData> displaylst = new List<ProductData>(); //ProductData is my Class.
foreach (var cat in Categories)
{
string prId = cat.Elements("id_products").Select(r => r.Value).FirstOrDefault();
List<string> Image = cat.Descendants("images").Elements("src").Attributes("largimage").Select(r => r.Value).ToList();
List<string> Image_code = cat.Descendants("images").Elements("src").Select(r => r.LastAttribute.Value).ToList();
int i = 0;
foreach (string img in Image)
{
displaylst.Add(new ProductData { Id = prId, Image = img, Image_code = Image_code[i] });
i++;
}
}
display.ItemsSource = displaylst;
Now on one button click i want to get the data of Product like prId,Image,Image_code where checkbox are checked from listview and put it into the simple list.
how can i did this please help me. thanks in advance.

First let's add a property to your ProductData class
public class ProductData
{
public string Id { get; set; }
public string Image { get; set; }
// I dont know exactly what's in this class
// ... more properties
// Add this one
public bool IsSelected { get; set; }
}
Now that we have a boolean IsSelected in our ProductData class we can know which are selected.
In the second foreach change this line
// Set IsSelected to false by default
displaylst.Add(new ProductData { IsSelected = false, Id = prId, Image = img, Image_code = Image_code[i] });
And bind the "IsChecked" property of your checkbox to IsSelected
<CheckBox IsChecked="{Binding Path=IsSelected}" Tag="{Binding Path=tag}" Visibility="{Binding Path=visichk}" Height="40" Name="addremove"
HorizontalAlignment="Center" Checked="add_checked" Unchecked="sub_checked" Opacity="0.5"
Background="White" VerticalAlignment="Top" Template="{StaticResource CheckboxImageTemplate}" >
With binding when you check one of the checkbox, the associed productData IsSelected property will become "true" automatically.
So now you just have to do a new list and select only ProductData where IsSelected is true:
List<ProductData> listOfSelectedProducts = (from product in displaylst
where product.IsSelected == true
select product).ToList();
Here you go you got a list of ProductData with only selected products.

binding data - inotifypropertychanged does not work

I have a listBox1 in which data are binding from the list. Then I want to when I select any item from listBox1 in listBox2 will binding data from another list.
private void listBox1_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
Teams teams = (Teams)listBox1.SelectedItems[0];
getH2hResults("//td[#class='hell']", teams.Team1, teams.Team2); // add elements to list
getH2hResults("//td[#class='dunkel']", teams.Team1, teams.Team2); // and here also
listBox2.ItemsSource = lists.h2hList;
}
On the first time this work, but for the twice time listBox2 doesn't displays new data.
public class Lists : BindableBase
{
public Lists()
{
_teamsList = new List<Teams>();
_h2hList = new List<H2H>();
}
private List<Teams> _teamsList;
public List<Teams> teamsList
{
get
{
return _teamsList;
}
set
{
if (value != _teamsList)
{
_teamsList = value;
RaisePropertyChanged("teamsList");
}
}
}
private List<H2H> _h2hList;
public List<H2H> h2hList
{
get
{
return _h2hList;
}
set
{
if (value != _h2hList)
{
_h2hList = value;
RaisePropertyChanged("h2hList");
}
}
}
}
And XAML
<ListBox Name="listBox1" Width="300" Height="300"
VerticalAlignment="Top"
HorizontalAlignment="Left"
ItemsSource="{Binding teamsList}" SelectionChanged="listBox1_SelectionChanged">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Foreground="#FF4273CD" Text="{Binding Team1, Mode=TwoWay}"></TextBlock>
<TextBlock Text=" vs " FontWeight="Bold"></TextBlock>
<TextBlock Foreground="#FF4273CD" Text="{Binding Team2, Mode=TwoWay}"></TextBlock>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<ListBox Name="listBox2" Grid.Column="1" Width="300" Height="300"
VerticalAlignment="Top"
HorizontalAlignment="Left"
ItemsSource="{Binding h2hList}" >
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Vertical">
<TextBlock Text="{Binding date, Mode=TwoWay}"></TextBlock>
<TextBlock Text="{Binding result, Mode=TwoWay}"></TextBlock>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>

RaisePropertyChanged("teamList");
is Wrong your propery is named 'teamsList' with an S,
change to:
RaisePropertyChanged("teamsList");
It is the public property you bind to and notify changes of,
edit:
also change your binding:
ItemsSource="{Binding teamList}"
to
ItemsSource="{Binding teamsList}"
Edit 2:
listBox2.DataContext = xxx
Not itemsource = xxx

With the line (in listBox1_SelectionChanged)
listBox2.ItemsSource = lists.h2hList;
you are effectively removing the binding from the ItemsSource property of listBox2.
Instead, you should only update the h2hList property in your Lists class (which presumably happens in getH2hResults) and remove the above line from your code.
Note however that it is not sufficient to clear and re-fill that list. You need to set the h2hList property in order to get a property change notification raised:
var newList = new List<H2H>();
// fill newList before assigning to h2hList property
lists.h2hList = newList;
If you want to keep the list and just change its elements, you would need to use ObservableCollection<H2H> instead of List<H2H> as collection type. This would be the better approach anyway, as you would not have to care for when exactly you add elements to a newly created collection.