C# 将itemsource与ObservableCollection绑定
可能重复:C# 将itemsource与ObservableCollection绑定,c#,silverlight,xaml,mvvm,C#,Silverlight,Xaml,Mvvm,可能重复: my Items控件的Itemsource绑定到ObservableCollection。如果ObservableCollection中没有对象,如何编写代码以显示文本“列表为空” <ItemsControl Grid.Row="2" Name="itemsControl2" ItemsSource="{Binding RecentPatients}"> 您可能可以使用TargetNullValue 见: 你可以像这样添加它 <ItemsControl Grid
my Items控件的Itemsource绑定到ObservableCollection。如果ObservableCollection中没有对象,如何编写代码以显示文本“列表为空”
<ItemsControl Grid.Row="2" Name="itemsControl2" ItemsSource="{Binding RecentPatients}">
您可能可以使用
TargetNullValue
见:
你可以像这样添加它
<ItemsControl Grid.Row="2" Name="itemsControl2" ItemsSource="{Binding RecentPatients, TargetNullValue=The list is empty}">
我使用了一种样式
<Style x:Key="{x:Type ItemsControl}" TargetType="{x:Type ItemsControl}">
<Style.Triggers>
<DataTrigger Binding="{Binding Items.Count, RelativeSource={RelativeSource Self}}" Value="0">
<Setter Property="Background">
<Setter.Value>
<VisualBrush Stretch="None">
<VisualBrush.Visual>
<TextBlock Text="The list is empty"
FontFamily="{StaticResource FontFamily}"
FontSize="{StaticResource FontSize}"/>
</VisualBrush.Visual>
</VisualBrush>
</Setter.Value>
</Setter>
</DataTrigger>
<DataTrigger Binding="{Binding Items, RelativeSource={RelativeSource Self}}" Value="{x:Null}">
<Setter Property="Background">
<Setter.Value>
<VisualBrush Stretch="None">
<VisualBrush.Visual>
<TextBlock Text="The list is empty"
FontFamily="{StaticResource FontFamily}"
FontSize="{StaticResource FontSize}"/>
</VisualBrush.Visual>
</VisualBrush>
</Setter.Value>
</Setter>
</DataTrigger>
</Style.Triggers>
</Style>
您也可以在C视图模型中执行此逻辑。无需更改xaml代码
public sealed partial class MainPage : Page, INotifyPropertyChanged {
private ObservableCollection<string> recentPatients = new ObservableCollection<string>();
private IList<string> emptyList = new string[] { "This list is empty" };
public MainPage() {
this.InitializeComponent();
this.DataContext = this;
this.recentPatients.CollectionChanged += OnCollectionChanged;
}
public IList<string> RecentPatients {
get { return recentPatients.Any() ? recentPatients : emptyList; }
}
private void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e) {
if (this.recentPatients.Count <= 1) {
// It could be a change between empty to non-empty.
this.OnPropertyChanged("RecentPatients");
}
}
// implement the INotifyPropertyChanged pattern here.
公共密封部分类主页面:第页,INotifyPropertyChanged{
私人可观察收集最近患者=新可观察收集();
private IList emptyList=新字符串[]{“此列表为空”};
公共主页(){
this.InitializeComponent();
this.DataContext=this;
this.recentPatients.CollectionChanged+=OnCollectionChanged;
}
公立医院近期病人{
获取{return recentPatients.Any()?recentPatients:emptyList;}
}
CollectionChanged的私有void(对象发送方,NotifyCollectionChangedEventArgs e){
如果(this.recentPatients.Count)很好,它是否可以使用空列表而不是空列表?很好,请选中此项: