In Avalonia Ui,
I have multiple layouts in my ui and I want a very specific tab order,
something like
<TextBox Tabindex="2">
<StackPanel>
<TextBox Tabindex="1">
</StackPanel>
<TextBox Tabindex="0">
that would result in using the tab-key cycling from bottom to top.
Is this possible? I found nothing.
I don't think so. KeyboardNavigation.TabIndex is not implmented yet: https://github.com/AvaloniaUI/Avalonia/issues/3025.
You have some limited Control using the functions provided in KeyboardNavigation and by using another control, for example a DockPanel or a Relative Panel.
Here is a very basic example for how you can use a DockPanel to do what you wish to:
<DockPanel LastChildFill="False"
VerticalAlignment="Top"
Name="TabOrderConatiner">
<TextBox Name="First" Tag="2" DockPanel.Dock="Top"></TextBox>
<TextBox Name="Third" Tag="0" DockPanel.Dock="Bottom"></TextBox>
<TextBox Name="Second" Tag="1" DockPanel.Dock="Top"></TextBox>
</DockPanel>
However it is like I said above limited compared to what TabIndex can provide.
Apart from that you should also be able to set the first TabItem when the container becomes active like that from your code-behind:
var tabOrderContainer = this.FindControl<DockPanel>("TabOrderConatiner");
var initialElement = this.FindControl<TextBox>("Third");
KeyboardNavigation.SetTabOnceActiveElement(tabOrderContainer, initialElement);
but I did not manage to get this to work...
Related
In the Universal Windows Platform API, how do I use x:Bind inside of a User Control (intended to be the layout for a GridView's ItemTemplate) to bind to instance properties of a GridView's ItemSource?
Background
I'm trying to re-create the layout found in Windows 10 stock apps like Sports, News, Money, etc.
I'm using a two GridViews for the main area of the app; one for "featured articles" (2 large photos w/ headlines) and one for all the other articles (smaller photos w/ headlines).
I'm able to bind to a data source that I supply in the code behind (a List where NewsItem is a POCO with a Image and Headline property) Here's the pertinent parts of the MainPage.xaml:
<Page ...
xmlns:data="using:NewsApp.Models" />
....
<GridView Name="FeaturedItems" Grid.Row="0">
<GridView.ItemTemplate>
<DataTemplate x:DataType="data:NewsItem">
<Grid Name="mainPanel" HorizontalAlignment="Stretch" Width="500" >
<Image Source="{x:Bind Image}" HorizontalAlignment="Stretch" />
<TextBlock Text="{x:Bind Headline}" />
</Grid>
</DataTemplate>
</GridView.ItemTemplate>
</GridView>
....
The Image and Headline bind just fine (even though they've not been styled correctly). However, instead I think I need to bind to a User Control to get the styling options I want, control over resizing esp. when using Visual State Triggers and to simplify the XAML in general (at least, this was the technique suggested to me.)
So, I added a new User Control to the project (FeaturedItemControl.xaml), and copied in the DataTemplate's child Grid:
<UserControl ... >
<Grid Name="mainPanel" HorizontalAlignment="Stretch" Width="500" >
<Image Source="{x:Bind Image}" HorizontalAlignment="Stretch" />
<TextBlock Text="{x:Bind Headline}" />
</Grid>
</UserControl>
And then back in the MainPage.xaml, I change the DataTemplate to reference the new FeaturedItemControl:
<GridView Name="FeaturedItems" Grid.Row="0">
<GridView.ItemTemplate>
<DataTemplate x:DataType="data:NewsItem">
<local:FeaturedItemControl HorizontalAlignment="Stretch" VerticalAlignment="Stretch" />
</DataTemplate>
</GridView.ItemTemplate>
</GridView>
However, I get the error message for both Image and Headline properties: Invalid binding path 'Headline': Property 'Headline' can't be found on type 'FeaturedItemControl'.
I've tried a few things but am flailing just throwing code at the problem without understanding what I'm doing. Any help would be greatly appreciated.
Thank you for your kind attention.
Using Depechie's answer, I formulated this little cheat cheat for posterity:
Do note that you MUST use this technique to utilize the VisualStateManager with items inside your data bound controls' (GridView, ListView) data templates.
1) Create a User Control.
2) Cut the content of the DataTemplate in your page and paste it into the User Control replacing the template's Grid.
3) Reference the User Control from inside the Data Template:
4) Modify the contents of the User Control changing x:Bind statements to utilize object.property notation:
<UserControl>
<StackPanel>
<Image Source="{x:Bind NewsItem.LeadPhoto}" />
<TextBlock Text="{x:Bind NewsItem.Headline}" />
<TextBlock Text="{x:Bind NewsItem.Subhead}" />
</StackPanel>
</UserControl>
5) Add this in the User Control's Code Behind:
public Models.NewsItem NewsItem { get { return this.DataContext as Models.NewsItem; } }
public ContactTemplate()
{
this.InitializeComponent();
this.DataContextChanged += (s, e) => Bindings.Update();
}
Well it's possible to use x:Bind in user controls, but you'll need to add some extra code behind.
I encountered the same problem in my project, you can see the result here : https://github.com/AppCreativity/Kliva/tree/master/src/Kliva/Controls
So what you need to do is, create a property in the code behind of your user control that points to the correct DataContext.
If you do that, you can use properties of that DataContext in the xaml of your control: for example:
Do note that in the constructor of your control you do need to add: DataContextChanged += (sender, args) => this.Bindings.Update(); because the datacontext will change depending on the page where your control is used!
Then on the page where you are placing this control, you'll also need to do the same to enable the x:bind to work.
You'll see this in my example on the MainPage.DeviceFamily-Mobile.xaml and MainPage.xaml.cs files.
Hope this helps.
x:Bind isn't really hierarchical like Binding/DataContext is. Additionally when you're not directly inside a DataTemplate (such as inside your user control) the object that x:Bind tries to use is 'this' rather than 'this.DataContext'. My current line of thinking on how to solve this sort of issue is to try not to use UserControls anywhere. Instead preferring DataTemplates contained within a ResourceDictionary. There are some pretty strong caveats to this approach though, you will for example crash the xaml compiler if you use x:Bind inside a data template that was created from the ResourceDictionary item template (add new item). you can find a pretty complete example here https://github.com/Microsoft/Windows-universal-samples/tree/master/Samples/XamlBind its important to note in the sample where they show the ResourceDictionary being used that its not actually just a ResourceDictionary.xaml its also a ResourceDictionary.xaml.cs (this is where the generated code from x:Bind ends up)
Another option is to add Headline and Image as properties on your user control and x:Bind them from the template, then inside the user control x:Bind as you are currently doing, but now the x:Bind generated path 'this.Headline' will exist. Unfortunately the order things are actually bound means that the x:Bind's you have inside your user control will have to be OneWay rather than the default OneTime. this is because x:Bind OneTime does the bind inside the InitializeComponent call, and any set of properties/DataContext stuff doesn't get done until after that has already run.
So to sum this up, you have two options, use data templates everywhere, or bind to properties that are directly on the user control.
I have the following code in which I hide a WebView just under the main Grid (LayoutRoot) so I can do a sliding animation later:
<Page...>
<Grid x:Name="LayoutRoot">
...
<Grid x:Name="ContentRoot">
...
</Grid>
<WebView...>
<WebView.RenderTransform>
<CompositeTransform TranslateY="{Binding ElementName=LayoutRoot,
Path=ActualHeight}"/> <!--Does not work-->
</WebView.RenderTransform>
</WebView>
</Grid>
</Page>
When I first type the {Binding ElementName=...} line into the designer, the WebView appears just below the Grid like it should. However, when I rebuild the solution or run the app, the WebView simply obscures the whole LayoutRoot.
This will happen regardless of what I am binding to/whatever the control is; however, binding to the exact same expression will show up properly in the designer and in the phone. To demonstrate what I am saying:
<Button Width="{Binding ElementName=LayoutRoot, Path=ActualHeight}"> <!--Works perfectly, both on designer and phone-->
<Button.RenderTransform>
<CompositeTransform SomeProperty={Binding ElementName=SomeElement, Path=SomePath}"/> <!--This does not work-->
</Button.RenderTransform>
</Button>
Is there any way to bind to LayoutRoot.ActualHeight short of writing C# code for this?
One problem you have is you are trying to bind to ActualHeight which is not a dependency property nor an observable (INotifyPropertyChanged) property, so the binding is only evaluated once when it's first created.
I'm new to windows mobile apps.
I have a pivot page and inside that there is multiple pivot items.
Inside the pivot item there is list picker which values are hard coded.
If there is more items in list picker all items show in a new page by default.
My issue is since all the item font are too small when opening the screen.
How can I change the font size of list picker items when those are opening.
My code like this.
<toolkit:ListPicker Grid.Row="0" Grid.Column="2" FontSize="21" Header="" Margin="10,12,-157,12" Background="White" Foreground="Black" BorderThickness="1" >
<sys:String>Convenience Eateries (CE)</sys:String>
<sys:String>Grocery Store (GS)</sys:String>
<sys:String>Secondary Network-ASD</sys:String>
<sys:String>Secondary Network-PSD</sys:String>
<sys:String>Cash and Carry</sys:String>
<sys:String>Modern Trade-Convenience Organized</sys:String>
<sys:String>Modern Trade-Grocery independent(SMMT)</sys:String>
<sys:String>HoReCa-Leisure outlets</sys:String>
<sys:String>HoReCa-Sports Clubs</sys:String>
<sys:String>HoReCa-Night Clubs</sys:String>
<sys:String>HoReCa-Karaoke</sys:String>
<sys:String>HoReCa-Casino</sys:String>
<sys:String>HoReCa-Café and Restaurant/Pubs</sys:String>
<sys:String>HoReCa-Other</sys:String>
<sys:String>Military-Welfare Shop</sys:String>
<sys:String>Military-Canteen</sys:String>
<sys:String>Convenience Mobile Outlets</sys:String>
<sys:String>Unconventional Outlets-Wine Stores</sys:String>
<sys:String>Unconventional Outlets-Other</sys:String>
</toolkit:ListPicker>
Try using ListPickerItem children instead of strings. They should have a better default look than shown above:
<toolkit:ListPicker>
<toolkit:ListPickerItem>Bob</toolkit:ListPickerItem>
<toolkit:ListPickerItem>Betty</toolkit:ListPickerItem>
<toolkit:ListPickerItem>Frank</toolkit:ListPickerItem>
<toolkit:ListPickerItem>Frank</toolkit:ListPickerItem>
</toolkit:ListPicker>
To change how the items look in the full mode page, you need to change the ListPicker's FullModeItemTemplate property. Something like this:
<toolkit:ListPicker>
<toolkit:ListPicker.FullModeItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding}" FontSize="25" />
</DataTemplate>
</toolkit:ListPicker.FullModeItemTemplate>
<sys:String>Convenience Eateries (CE)</sys:String>
<sys:String>Grocery Store (GS)</sys:String>
<!-- Hard coded values go here, just as in your code. -->
</toolkit:ListPicker>
I want to show the current index of an item in an itemscontrol:
<TextBlock Foreground="#ffffffff" Margin="8,8,2,2" TextWrapping="Wrap" Text="{Binding RelativeSource={RelativeSource Mode=TemplatedParent}, Path=Items.CurrentIndex}" Grid.Column="0" Grid.Row="0" HorizontalAlignment="Right"/>
This is my best guess. I've come across many possible solutions, but working with alternationcount (not supported in silverlight as it seems) or other didn't give me a result.
The itemscontrol looks like this:
<ItemsControl Grid.Column="0" Grid.ColumnSpan="3" HorizontalAlignment="Stretch" Grid.Row="6" ItemsSource="{Binding Alternatives, Mode=TwoWay}" ></ItemsControl>
The list bound to the itemscontrol is a simple object with some properties.
I really like to do this in XAML, as we reuse that object on alot of pages.
Any good suggestions would be great.
PS: I don't want the index after interaction from the user, it should be retrieved automatically.
if you want the index of an item in an itemscontrol - it just make sense for me if there is some sort of selection. but the itemsscontrol has no selector and so no selection and so no selectionchanged event. so if you want some selection take listbox
one more thing
<ItemsControl ItemsSource="{Binding Alternatives, Mode=TwoWay}" ></ItemsControl>
mode=twoway makes no sense, cause your itemsscontrol will never set the underlining source.
EDIT: i just assume what you want from your comment. you can use a ICollectionView to iterate through your items. but your Itemscontrol can not show this of course. but you can alter the item itself to show the iteration
ICollectionView view = CollectionViewsource.GetDefaultView(Alternatives);
view.CurrentChanged += (s,a) =>
{
var current = this.view.CurrentItem;
//to stuff with your current item here
};
elsewhere where you want to iterate
view.MoveCurrentToNext();
you should handle first and last item and that stuff too.
I have a windows phone 7 app with some xaml that looks like:
<Grid x:Name="ContentGrid" Grid.Row="1">
<ItemsControl x:Name="MyView" ItemTemplate="{StaticResource MyInner}"/>
</Grid>
The item template here looks like:
<DataTemplate x:Key="MyInner">
<ItemsControl ItemsSource="{Binding}" ItemTemplate="{StaticResource MyInner_Item}">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Horizontal"/>
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
</ItemsControl>
</DataTemplate>
And finally, the MyInner_Item template looks like:
<DataTemplate x:Key="MyInner_Item">
<Button x:Name="MyButton">
<Button.Template>
<ControlTemplate>
<Border HorizontalAlignment="Center" VerticalAlignment="Center" x:Name="myborder">
<Image Source="{Binding Path=ImageUri}" Width="{Binding Path=Width}" Height="{Binding Path=Height}" Stretch="Fill" />
</Border>
</ControlTemplate>
</Button.Template>
</Button>
</DataTemplate>
So, it's an ItemsControl, which contains an ItemsControl, which contains buttons. This essentially creates a 2D array of buttons.
What I want to do is add an event handler to the Click event of the buttons.
Here's the catch: the code that sits behind this is written in F#. I can't, to the best of my knowledge, specify my event handler in the XAML, as F# doesn't talk to WPF in any nice way. So I need to add my event handler(s) manually in code.
Is there an easy way of doing this?
Currently, I have some F# which looks like:
let myView : ItemsControl = this?MyView
do myView.ItemsSource <- viewModel.BoardData
Here, the BoardData is a list of lists.
I was wondering if it's possible to loop through the controls in the ItemsControl, to add my event handlers? I'm having a bit of trouble doing this though. For example, in the following:
let container = myView.ItemContainerGenerator.ContainerFromItem(myView.Items.[0])
...sets container to null. In fact, all the methods I've tried from myView.ItemContainerGenerator returns null.
So, how should I go about attaching my event handler, so that I can respond to the buttons being clicked?
I have not done any Windows 7 Phone development, but I have done plenty of XAML + Silverlight development with C# and now I'm getting into doing some F# development. The approach I would take is by not using event handler's at all. Since you are using a button, make a class that derives from ICommand and add that type as a public property on your ViewModel so you could bind it to the Command property of the button. The benefits of using the ICommand interface over event handlers is that you could also have a condition on when the button is enabled to do the action.
Also, take notice that when you are doing binding expressions within (i.e. ItemTemplate) items in an ItemsControl control, the scope of what properties you can bind to are reduced to the properties of the current item. So all of the properties of the ViewModel are out of scope, unless you specify it fully i.e. <Button Command={Binding Source=ViewModel, Path=Property1.Property2.etc} />. Let me know if this helped.