I have an UWP XAML named MyPage.xaml like below
<Page
x:Class="AffiliaTool.Lib.View.BrowserWindowView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:core="using:Microsoft.Xaml.Interactions.Core"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:i="using:Microsoft.Xaml.Interactivity"
xmlns:local="using:AffiliaTool.Lib.View"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:tk="using:Microsoft.Toolkit.Uwp.UI.Controls"
xmlns:vm="using:AffiliaTool.Lib.ViewModel"
mc:Ignorable="d">
<tk:TabView x:Name="TabViewBar" />
</Page>
And from other class, I want to instantiate that class and manipulate TabView programmatically like below
var mypage = new MyPage();
mypage.TabViewBar.Visibility = Windows.UI.Xaml.Visibility.Collapsed;
I used to be able to access Child element programmatically from other class when coding WPF, but why can't I do that in UWP but from codebehind? Anyway to go around this?
Thanks
You can. Just add a FieldModifier like this:
<tk:TabView x:Name="TabViewBar" x:FieldModifier="public"/>
then you can access TabViewBar from another class.
Hope that helps.
Related
Why can't my custom ListView have it's own xaml file? I have a custom Button and it works with a xaml file with no issues, but not my ListView. The main reason I want to use this approach (rather than be forced to create a Style that is place in the Generic.xaml file) is because I would like to take advantage of the Resources element and place all resources related to the listview within the xaml file:
public sealed partial class MyListView : ListView
{
public MyListView()
{
this.InitializeComponent();
}
}
And here is the associated xaml file:
<ListView
x:Class="App1.MyListView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:App1"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
d:DesignHeight="300"
d:DesignWidth="400">
<ListView.Resources>
<!-- I would like to place all related resources here instead of having
them placed in external locations, and then have to open different files to find them. -->
</ListView.Resources>
</ListView>
Although I would expect this should work as well, it seems that this problem is present and it is recommended to use the templated control instead.
I suppose the problem is that assigning the compiler is unable to generate the valid assignment to the Items property of the control, which it is trying to construct from the content of the element. Even when the element is closed immediately it seems to be an issue.
Why not place resources on the Page or inside ListView, rather than deriving your own control?
<Page
x:Class="ListViewResources.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:ListViewResources"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Page.Resources>
<!-- Place all related resources here instead of having them placed in external locations, and then have to open different files to find them. -->
</Page.Resources>
<ListView x:Name="MyListView">
<ListView.Resources>
<!-- Or place related resources here -->
</ListView.Resources>
</ListView>
</Page>
I am porting a Silverlight application to UWP Windows 10 app.
Large part of it has controls, inherited from a class, which inherits from UserControl.
base:
public abstract class PartBase : UserControl, IPart, IDisposable
concrete:
public sealed partial class MyPart : PartBase
its XAML:
<local:PartBase
I get compilation error : The name "PartBase" does not exist in the namespace ..
Is inheritance permitted in UWP ?
Your code should work. I've created your abstract base class and a new control based on that class.
<local:PartBase
x:Class="UWPTest.Controls.MyUserControl1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:UWPTest.Controls"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
d:DesignHeight="300"
d:DesignWidth="400">
<Grid>
<Button>Test</Button>
</Grid>
</local:PartBase>
Double check that the xmlns:local="using:UWPTest.Controls" is correct with the namespace PartBase is declared in. Then rebuild your solution and the error should go away (you will see the error if you don't rebuild).
On a page (e.g. MainPage) I can simply use the control:
<Page
x:Class="UWPTest.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:controls="using:UWPTest.Controls"
mc:Ignorable="d">
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<controls:MyUserControl1 />
</Grid>
</Page>
Note the xmlns:controls pointing to the correct namespace. The designer will also give an error until you rebuild the app.
Everything builds here and the application runs, so if you still have the error after double checking all namepace declarations you'll have to put a repro online so we can check what else goes wrong.
Hi i just recently found out that you can use components from WPF and add into windows form just by creating them and later adding then into the form as element Host
So what i am trying to do is to create a video player using MediaElement and i also know that you can use Direct X or use Windows Media player for this put i want to custom make some controls in this so here is my question
when i try to add a the media element into my windows form it give me this error
here's my code for the mediaelement wpf
<UserControl x:Class="Videoplayer_2._0.MediaPlayer"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:Videoplayer_2._0"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<Grid>
<MediaElement x:Name="mediaElement" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" />
</Grid>
</UserControl>
So is adding mediaElement just doesn't work or i did something wrong and also i added a WPF slider into the form also just saying because i have no idea if it will affect it or not
You just need to restart Visual Studio I think.
I'm currently getting started with XAML and I have a question regarding how to define the DataContext of an element.
I've created a View that includes a Page with the following markup:
<Page x:Class="View.MainView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:ViewModel="clr-namespace:ViewModel"
mc:Ignorable="d"
Title="MainView">
...
</Page>
When I want to give this Page a DataContext to be used by child elements, this works:
<Page x:Class="View.MainView"
...
mc:Ignorable="d"
Title="MainView">
<Page.DataContext>
<ViewModel:MainViewModel />
</Page.DataContext>
...
</Page>
And this doesn't:
<Page x:Class="View.MainView"
...
mc:Ignorable="d"
Title="MainView" DataContext="ViewModel:MainViewModel">
...
</Page>
For me, it looks like the Page element expects the DataSource to be defined as a XAML property and not as an attribute. However, the IntelliSense in Visual Studio offers me a DataContext attribute for the Page, so I guess I'm just using a wrong syntax here. Can you point that out to me?
Thanks!
You can use the attribute to specify the DataContext, but you should consider how does your viewmodel get instantiated.
Using a property in this way
<Page.DataContext>
<ViewModel:MainViewModel />
</Page.DataContext>
you tell WPF to instantiate the MainViewModel and to assign the created object to the DataContext property of the Page.
With an attribute, you just specify a string in that case:
DataContext="ViewModel:MainViewModel"
But you want WPF to create an instance for you.
So you can use e.g. a Binding or a StaticResource / DynamicResource to assign a created instance to the DataContext property:
DataContext="{Binding ViewModel}"
or
<Page DataContext="{StaticResource ViewModel}">
<Page.Resources>
<ViewModel:MainViewModel x:Key = "ViewModel"/>
</Page.Resources>
</Page>
I want to make a converter class , I implemented it and i want to use it in another xaml class
So i write this code
<UserControl
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:PoliceApp"
xmlns:common="using:PoliceApp.Common"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<UserControl.Resources>
<local:TitleToImgConverter x:Key="BoolOrConverter"/>
</UserControl.Resources>
</UserControl>
It tells me that there is a missing attribute for user control
and my first code was
DataContext="{Binding DefaultViewModel, RelativeSource={RelativeSource Self}}"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:PoliceApp"
xmlns:common="using:PoliceApp.Common"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<UserControl.Resources>
<local:TitleToImgConverter x:Key="BoolOrConverter"/>
</UserControl.Resources>
And the error was "The name titletoimgconverter doesnt exist in the namespace using:policeApp"
This is normal (at least, I have never seen it otherwise) when you have just created a new converter and added it as a resource in your XAML code. XAML code often lags behind when something is added to the namespace.
The solution for this is to rebuild your entire project. The XAML should now be able to locate your converter, and the error should disappear.
Update
If your converter exists in some folder called Converter, you should use your first example, and replace xmlns:local="using:PoliceApp" with xmlns:local="clr-namespace:PoliceApp.Converter". If it just resides in your main folder, you can leave out the .Converter. Note that I've replaced the using: with clr-namespace:.