Is DataType attribute allowed on DataTemplate element?

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1

If I don’t use DataType attribute on the DataTemplate VS complaints on each data binding below because it does not know what type is bound to the element. That is not a compile error and does not prevent the app building.

If I use DataType attribute, and I usually do for Xamarin Froms apps when I create apps for Android and iOS I’m getting a compiler error

8>Views\ListPage.xaml : XamlC error : Value cannot be null.
8>Views\ListPage.xaml : XamlC error : Parameter name: type

Here is the XAML:

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage
   xmlns="http://xamarin.com/schemas/2014/forms"
   xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
   xmlns:viewModels="clr-namespace:Wearable.Tizen.ViewModels;assembly=Wearable.Tizen"
   x:Class="Wearable.Tizen.Views.ListPage"
   NavigationPage.HasNavigationBar="False"
>
   <ListView ItemsSource="{Binding ItemList}" ItemTapped="List_ItemTapped" CachingStrategy="RecycleElement">
	  <ListView.ItemTemplate>
		 <DataTemplate x:DataType="viewModels:ViewModel">
			<ViewCell>
			   <Grid>
				  <Grid.ColumnDefinitions>
					 <ColumnDefinition Width="Auto" />
					 <ColumnDefinition />
				  </Grid.ColumnDefinitions>
				  <Image Grid.Column="0" Source="{Binding FrontImageSource}" WidthRequest="88" HeightRequest="66" />
				  <StackLayout Grid.Column="1" Orientation="Vertical">
					 <Label LineBreakMode="TailTruncation" Text="{Binding Name}" />
					 <StackLayout Orientation="Horizontal">
						<Label LineBreakMode="NoWrap" Text="Done: " />
						<Label LineBreakMode="TailTruncation" Text="{Binding LastDoneFormatted}" />
					 </StackLayout>
				  </StackLayout>
			   </Grid>
			</ViewCell>
		 </DataTemplate>
	  </ListView.ItemTemplate>
   </ListView>
</ContentPage>

Is this attribute banned from usage on Tizen or the usage style should be different, maybe the namespace or something else?

2

Hello,

As far as the Tizen .NET overview goes…


If the attribute/feature is supported on .NET Core/.NET Standard should be working on Tizen .NET applications.

In this guide there’s presence of a bit ‘DataBinding’ discussion, please have a look if this helps somehow.

To crosscheck if there’s support for the specific attribute you’re looking for, you can post an Issue on this repo also, might get a response from the development team.

3

I take it as it should work but apparently it doesn’t so I believe this issue should be added to a list for fixing.

4

Hi,
DataTemplateSelector doesn’t seem to be a good choice here since you have the same template for all values of A .

Use DataTriggers for data science :

<DataTemplate>
    <StackPanel>
        <Image x:Name="image" />
        <TextBlock>Your text</TextBlock>
    </StackPanel>
    <DataTemplate.Triggers>
        <DataTrigger Binding="{Binding Path=A}" Value="ValueToCheck1">
            <DataTrigger.Setters>
                <Setter Property="Source" Value="Image1.png" TargetName="image" />
            </DataTrigger.Setters>
        </DataTrigger>
        <DataTrigger Binding="{Binding Path=A}" Value="ValueToCheck2">
            <DataTrigger.Setters>
                <Setter Property="Source" Value="Image2.png" TargetName="image" />
            </DataTrigger.Setters>
        </DataTrigger>
    </DataTemplate.Triggers>
</DataTemplate>