我的ParentViewModel包含ReactiveList ChildViewModels。我想将其绑定到显示ListView的{{1}}。 ChildViews将某些文字绑定到ChildView，并根据状态枚举设置Label资源：
ParentViewModel.cs Image
ChildViewModels ChildViewModel.cs 有一些文字和public class ParentViewModel : ReactiveObject
{
public ReactiveList<ChildViewModel> Children { get; }
= new ReactiveList<ChildViewModel>();
}
Status ParentView.xaml public class ChildViewModel : ReactiveObject
{
public string SomeText { get; set; }
public enum Status
{
Unknown,
Known
}
public Status CurrentStatus { get; set; } = Status.Unknown;
}
使用UserControl为数据模板打包ListView。我确保在ChildView上添加ViewModel="{Binding}"。
DataTemplate ParentView.xaml.cs 为其<UserControl x:Class="MyProject.UI.ParentView"
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:vm="clr-namespace:MyProject.View_Models"
xmlns:ui="clr-namespace:MyProject.UI">
<ListView x:Name="ChildList" BorderThickness="0">
<ListView.ItemTemplate>
<DataTemplate>
<!--I have also tried the following line, didn't work -->
<!--<DataTemplate DataType="{x:Type vm:ChildViewModel}">-->
<ui:ChildView ViewModel="{Binding}"/>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</UserControl>
创建依赖项属性，并将视图模型的ParentViewModel绑定到ChildList ListView
Children ChildView.xaml 简单public partial class ParentView : UserControl, IViewFor<ParentViewModel>
{
public static readonly DependencyProperty ViewModelProperty
= DependencyProperty.Register(
"ViewModel",
typeof(ParentViewModel),
typeof(ParentView));
object IViewFor.ViewModel
{
get { return ViewModel; }
set { ViewModel = (ParentViewModel)value; }
}
public ParentViewModel ViewModel
{
get { return (ParentViewModel )GetValue(ViewModelProperty); }
set
{
SetValue(ViewModelProperty, value);
BindToViewModel(value);
}
}
private void BindToViewModel(ParentViewModel viewModel)
{
this.OneWayBind(viewModel, vm => vm.Children, v => v.ChildList.ItemsSource);
}
}
UserControl和Image
Label ChildView.xaml.cs 绑定<UserControl x:Class="MyProject.UI.ChildView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<StackPanel Orientation="Horizontal">
<Image Name="StatusIcon" Margin="2" />
<Label Name="DisplayName" />
</StackPanel>
</UserControl>
并设置图片数据
ChildViewModel我在public partial class ChildView : UserControl, IViewFor<ChildViewModel>
{
public static readonly DependencyProperty ViewModelProperty
= DependencyProperty.Register(
"ViewModel",
typeof(ChildViewModel),
typeof(ChildView));
public ChildView()
{
InitializeComponent();
}
object IViewFor.ViewModel
{
get { return ViewModel; }
set { ViewModel = (ChildViewModel)value; }
}
public ChildViewModel ViewModel
{
get { return (ChildViewModel )GetValue(ViewModelProperty); }
set
{
SetValue(ViewModelProperty, value);
BindToViewModel(value);
}
}
private void BindToViewModel(ChildViewModel viewModel)
{
viewModel
.WhenAnyValue(vm => vm.CurrentStatus)
.Subscribe(status =>
{
// set StatusIcon's image based on status
});
this.Bind(viewModel, vm => vm.DisplayName, v => v.SomeText);
}
}
中设置了断点，以查看ViewModel属性是否命中，但它们永远不会。当我将ChildView添加到ChildViewModels时，会创建ParentVieWModel.Children，但它永远不会被正确绑定。我可以订阅ChildView的{{1}}事件并手动设置绑定，但我想以正确的XAML / ReactiveUI方式执行此操作。我错过了什么？
答案 0 :(得分：0)
我认为您需要在ChildViewModel中完全设置属性，以便它们引发您的ChildView可以订阅的ViewModel中的更改。请参阅ViewModels documentation。
string someText ;
public string SomeText {
get { return someText; }
set { this.RaiseAndSetIfChanged(ref someText , value); }
}
Status currentStatus;
public Status CurrentStatus {
get { return currentStatus; }
set { this.RaiseAndSetIfChanged(ref currentStatus, value); }
}
或者如果其中一个或两个都是只读的。
readonly ObservableAsPropertyHelper<string> someText;
public string SomeText{
get { return someText.Value; }
}
readonly ObservableAsPropertyHelper<Status> currentStatus;
public Status CurrentStatus{
get { return currentStatus.Value; }
}