在 Avalonia ItemsControl 中选择基于 ViewModel 类型的 DataTemplate
Selecting a DataTemplate based on ViewModel type in Avalonia ItemsControl
里面有UserControl和ItemsControl,需要根据Items集合元素类型显示不同DataTemplate的items。
以下 TemplateSelector 和 XAML 根据此答案创建的 ()
<ItemsControl Items="{Binding Items}">
<ItemsControl.DataTemplates>
<views:ItemsTemplateSelector>
<DataTemplate x:Key="{x:Type itemViewModels:Item1ViewModel}">
<itemsViews:Item1View/>
</DataTemplate>
<DataTemplate x:Key="{x:Type itemViewModels:Item2ViewModel}">
<itemsViews:Item2View/>
</DataTemplate>
</views:ItemsTemplateSelector>
</ItemsControl.DataTemplates>
</ItemsControl>
public ItemsViewModel()
{
this.Items = new ObservableCollection<IItemViewModel>();
this.Items.Add(new Item1ViewModel("Item1"));
this.Items.Add(new Item2ViewModel("Item2"));
}
public ObservableCollection<IitemViewModel> Items { get; }
public class ItemsTemplateSelector : IDataTemplate
{
public bool SupportsRecycling => false;
[Content]
public Dictionary<Type, IDataTemplate> Templates { get; } = new Dictionary<Type, IDataTemplate>();
public IControl Build(object data)
{
var type = data.GetType();
var template = this.Templates[type];
var control = template.Build(data);
return control;
}
public bool Match(object data)
{
return data is IItemViewModel;
}
}
public interface IItemViewModel
{
string Name { get; }
}
public class Item1ViewModel : IItemViewModel
{
public Item1ViewModel (string name)
{
this.Name = name;
}
public string Name { get; }
}
<UserControl
xmlns="https://github.com/avaloniaui"
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"
x:Class="Desktop.Views.Items.Item1View">
<TextBlock Text="{Binding Name}"/>
</UserControl>
运行时出现异常:
Avalonia.Markup.Xaml.XamlLoadException: 'No precompiled XAML found for Desktop.Views.Items.Item1View, make sure to specify x:Class and include your XAML file as AvaloniaResource'
如果在 ItemsControl 而不是 <itemsViews:Item1View/>
中指定 <TextBlock Text="{Binding Name}"/>
,则一切正常。但我想将每个项目的标记拆分为一个单独的 XAML 文件,其中包含单独的 ViewModel。项目可以完全不同。
是否可以解决这个问题,让 ItemsControl select 一个基于 ViewModel 类型的 DataTemplate?
为了解决这个问题,我手动编辑了项目文件 *.csproj 添加了 AvaloniaResource 元素
<AvaloniaResource Include="..\Desktop\Views\Items*.xaml">
<SubType>Designer</SubType>
</AvaloniaResource>
里面有UserControl和ItemsControl,需要根据Items集合元素类型显示不同DataTemplate的items。
以下 TemplateSelector 和 XAML 根据此答案创建的 (
<ItemsControl Items="{Binding Items}">
<ItemsControl.DataTemplates>
<views:ItemsTemplateSelector>
<DataTemplate x:Key="{x:Type itemViewModels:Item1ViewModel}">
<itemsViews:Item1View/>
</DataTemplate>
<DataTemplate x:Key="{x:Type itemViewModels:Item2ViewModel}">
<itemsViews:Item2View/>
</DataTemplate>
</views:ItemsTemplateSelector>
</ItemsControl.DataTemplates>
</ItemsControl>
public ItemsViewModel()
{
this.Items = new ObservableCollection<IItemViewModel>();
this.Items.Add(new Item1ViewModel("Item1"));
this.Items.Add(new Item2ViewModel("Item2"));
}
public ObservableCollection<IitemViewModel> Items { get; }
public class ItemsTemplateSelector : IDataTemplate
{
public bool SupportsRecycling => false;
[Content]
public Dictionary<Type, IDataTemplate> Templates { get; } = new Dictionary<Type, IDataTemplate>();
public IControl Build(object data)
{
var type = data.GetType();
var template = this.Templates[type];
var control = template.Build(data);
return control;
}
public bool Match(object data)
{
return data is IItemViewModel;
}
}
public interface IItemViewModel
{
string Name { get; }
}
public class Item1ViewModel : IItemViewModel
{
public Item1ViewModel (string name)
{
this.Name = name;
}
public string Name { get; }
}
<UserControl
xmlns="https://github.com/avaloniaui"
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"
x:Class="Desktop.Views.Items.Item1View">
<TextBlock Text="{Binding Name}"/>
</UserControl>
运行时出现异常:
Avalonia.Markup.Xaml.XamlLoadException: 'No precompiled XAML found for Desktop.Views.Items.Item1View, make sure to specify x:Class and include your XAML file as AvaloniaResource'
如果在 ItemsControl 而不是 <itemsViews:Item1View/>
中指定 <TextBlock Text="{Binding Name}"/>
,则一切正常。但我想将每个项目的标记拆分为一个单独的 XAML 文件,其中包含单独的 ViewModel。项目可以完全不同。
是否可以解决这个问题,让 ItemsControl select 一个基于 ViewModel 类型的 DataTemplate?
为了解决这个问题,我手动编辑了项目文件 *.csproj 添加了 AvaloniaResource 元素
<AvaloniaResource Include="..\Desktop\Views\Items*.xaml">
<SubType>Designer</SubType>
</AvaloniaResource>