I am new to the XAML world and I'm fumbling my way through a lot of tutorials. One thing i'm stuck on is calling the .tostring on an object.
Here is mysetup
I have a listbox that is bound to a list of objects
I have a contentControl bound to the same list that displays the selected item from the listbox.
My ContentControl is as follows:
<ContentControl Grid.Row="1" Margin="0,3,5,204" Name="Detail"
Content="{Binding Source={StaticResource listingDataView}}"
ContentTemplate="{StaticResource myContentTemplate}"
HorizontalAlignment="Right" Width="231"/>
in myContentTemplate I have:
<DataTemplate x:Key="myContentTemplate">
<StackPanel>
<TextBlock Text="{Binding Path=Name}" />
<!-- want to call .tostring here-->
</StackPanel>
</DataTemplate>
In the template I'd like to call .tostring on the object that is currently selected but i cant figure out how to do that?
thanks
Steph
well looks like i asked this too soon. I found the answer in another question
How to reference current object in XAML
Quoting the answer from that thread:
According to the Data Binding
Overview, you can use the "/" to
indicate the current item. You can
then navigate up and down the tree as
needs be using the following type
syntaxes:
Button Content="{Binding }" />
Button Content="{Binding Path=/}" />
Button Content="{Binding
Path=/Description}" />
Hope this helps someone else :)
Related
I'm new to this community / Xamarin, and I've been stuck on this for a while so I need to reach out for help now.
I have a CarouselView of ContentViews and one of the view pages need to be validated so when the field is empty, I can revert back the correct carousel page using the Current Item binding BUT - although I am correctly retrieving the current item and the content view, the UI/binding isn't updating.
ContentViews is the ObservableCollection.
<Label Text="{Binding Source={x:Reference carouselView}, Path=CurrentItem,
StringFormat='Current item: {0}', FallbackValue='Current item:'}"/>
<Label Text="{Binding Source={x:Reference carouselView}, Path=Position,
StringFormat='Position: {0}'}"/>
<CarouselView
x:Name="carouselView"
IndicatorView="indicatorView"
ItemsSource="{Binding ContentViews}"
CurrentItem="{Binding CurrentItem}"
Position="{Binding Position}"
CurrentItemChanged="OnCurrentItemChanged"
PositionChanged="OnPositionChanged">
<CarouselView.ItemTemplate>
<DataTemplate>
<ContentView Content="{Binding .}" />
</DataTemplate>
</CarouselView.ItemTemplate>
</CarouselView>
Do you have INotifyPropertyChanged implemented in you Binding Source?
check this , also check that the CarouselView Binding source is your desired class.
I feel like I'm missing something obvious because this is so simple. Thanks in advance for the help. I'm struggling with binding the SelectedItem of a simple ListView in a Xamarin application. I'm testing on UWP and am using Prism's MVVM BindableBase base class. Here's what I'm experiencing:
The page loads and nothing in the list is selected.
I select an item in the list.
The setter of SelectedGrade is called with a value of null.
After that, selecting items does not cause the SelectedGrade setter to be called.
Here's the relevant XAML:
<ListView BackgroundColor="#7F7F7F"
CachingStrategy="RecycleElement"
IsPullToRefreshEnabled="True"
IsRefreshing="{Binding IsBusy, Mode=OneWay}"
ItemsSource="{Binding Grades, Mode=OneWay}"
SelectedItem="{Binding SelectedGrade, Mode=TwoWay}"
RefreshCommand="{Binding RefreshCommand}"
RowHeight="50">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout HorizontalOptions="FillAndExpand"
VerticalOptions="CenterAndExpand"
Orientation="Horizontal"
Padding="10">
<Label HorizontalOptions="FillAndExpand"
Text="{Binding Title}"
TextColor="#272832"/>
<Label HorizontalOptions="FillAndExpand"
Text="{Binding Score}"
TextColor="Aquamarine" />
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
Here's the ViewModel:
Grade _selectedGrade;
public Grade SelectedGrade
{
get { return _selectedGrade; }
set { SetProperty(ref _selectedGrade, value); } // this gets set to NULL the first time i select an item then never gets set again
}
Edit: I've also added an ItemSelected event listener in the code-behind and it is not being fired after the initial item is selected. The one time it is fired, the SelectedItemChangedEventArgs reveal that the ListView's SelectedItem is null. I can also see at this time that the ListView's ItemsSource has a collection of three items in it, as I would expect. I'm quite confused as to why the ListView thinks the SelectedItem is null and why it is not broadcasting when the selected item changes.
It looks like this was a bug in Xamarin. I upgraded from Xamarin.Forms 3.0.0.550146 to 3.1.0.637273 and now it works.
I have faced with the similar issue when List does not bind to view model with SelectedItem and Xamarin forms 5.0.0.2244.
It was resolved with setting default value of List property to new List() object instead null value in the view model before setting binding context . After that binding has became working.
I have Windows Phone 8 page which has a number of controls on it, some of them are LongListSelector controls. If all collections have content everything is displayed correctly.
But if any of the collections bound to the lists are empty all controls below them on the page disappear, i.e. the page looks to be truncated as lots of things are missing.
If I add code to make sure to add at least on item to each collection the page display correctly.
The databinding is done using C#, as shown below.
XAML
<phone:LongListSelector Grid.Row="3" x:Name="PicturesGrid">
<phone:LongListSelector.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center">
<Image Source="{Binding Filename}" />
</StackPanel>
</DataTemplate>
</phone:LongListSelector.ItemTemplate>
</phone:LongListSelector>
C#
PicturesGrid.ItemsSource = App.ViewModel.SelectedBird.Pictures;
Update: I have noticed that there is a scrollbar present, but however much I scroll I never get down to the bottom.
On my MainWindow.xaml page, I have the following code which works (where MyWord is a string)
<ContentControl Content="{Binding MyWord}" />
I'm playing with DataTemplates and trying understand them. So, I want to reference a DataTemplate from within my ContentControl. The DataTemplate should contain a TextBlock which binds to my string. I updated my code
<ContentControl ContentTemplate="{StaticResource ViewsTemplate}" />
And in my ResourceDictionary I add
<DataTemplate x:Key="ViewsTemplate">
<TextBlock Text="{Binding MyWord}" />
</DataTemplate>
This produces no text on screen at all. I even tried
<ContentControl Content="{Binding MyWord}" ContentTemplate="{StaticResource ViewsTemplate}" />
and still no result on screen.
I can't work out why can any one give some advice please.
Thank you
The ContentControl still needs to have some content bound to it.
<ContentControl ContentTemplate="{StaticResource ViewsTemplate}" Content="{Binding MyWord}" />
Would work, but then you'd need to change your data template because it expects to be able to find MyWord which of course it won't be able to, so you'd want to use just {Binding} instead.
Alternatively, bind the ContentControl's Content to {Binding} - the current DataContext of its parent - and leave the template as it is.
I have a window with a TabControl that i've bind to a list of objec, I'll called MyItem :
<TabControl Name="MyTabPNL" Background="Gainsboro"
ItemsSource="{Binding MyItemList, ElementName=WatcherWindow}"
ContentTemplate="{StaticResource tabItemTemplate}">
</TabControl>
This MyItem class has an ObservableCollection, that I want to bind to a Listview, I'm doing this with a DataTemplate.
GOAL: I'd like to sort automatically this ObservableCollection in XAML. Usually i would use a CollectionViewSource, but i can't find a way to this... I've tried stuff like that:
<DataTemplate x:Key="tabItemTemplate">
<DataTemplate.Resources>
<CollectionViewSource x:Key='dayList' Source="{Binding MyDayList}">
<CollectionViewSource.SortDescriptions>
<scm:SortDescription PropertyName="MyDate" Direction="Descending" />
</CollectionViewSource.SortDescriptions>
</CollectionViewSource>
</DataTemplate.Resources>
<Grid >
<ListView ItemsSource="{Binding Source={StaticResource dayList}}" >
<ListView.View>
<GridView x:Name="gridvwDay" >
<GridViewColumn Header="MyDate"
CellTemplate="{StaticResource myCellTemplatePNLDate}"
HeaderContainerStyle="{StaticResource CustomHeaderStyleNeutral}"
Width="70" />
</GridView>
</ListView.View>
</ListView>
</Grid>
But everytime i've got the same error:
System.Windows.Data Error: 2 : Cannot
find governing FrameworkElement or
FrameworkContentElement for target
element.
BindingExpression:Path=MyDayList;
DataItem=null; target element is
'CollectionViewSource'
(HashCode=58368655); target property
is 'Source' (type 'Object')
I can't find a way to make a link between the dayList in the ListView ItemsSource, and the dayList in the CollectionRessource.
Do you guys have an idea?
FYI: pre sorting the ObservableCollection is not doable, because of the nature of the Class i'm using.
Have you tried simply,
<ListView ItemsSource="{StaticResource dayList}">
As per the doc: http://msdn.microsoft.com/en-us/library/ms750950.aspx
You don't need to bind when its just static on the page :)