Question

所以我有public class WiresharkFiles : INotifyPropertyChanged { public ObservableCollection<WiresharkFile> List { get; set; } public event PropertyChangedEventHandler PropertyChanged; private bool _inUse; private int _packets; private bool _hasItems; public WiresharkFiles() { List = new ObservableCollection<WiresharkFile>(); HasItems = false; List.CollectionChanged += List_CollectionChanged; } private void List_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e) { HasItems = List.Count > 0; } public bool InUse { get { return _inUse; } set { _inUse = value; NotifyPropertyChanged("InUse"); } } public int Packets { get { return _packets; } set { _packets = value; NotifyPropertyChanged("Packets"); } } public bool HasItems { get { return _hasItems; } set { _hasItems = value; NotifyPropertyChanged("HasItems"); } } private void NotifyPropertyChanged([CallerMemberName] String propertyName = "") { PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName)); } }：

private WiresharkFiles caps;

public MainWindow()
{
    InitializeComponent(); 
    caps = new WiresharkFiles();
}

MainWindow.xaml

<Window.Resources>
   <Convertors:CollectionHasItemsConverter x:Key="CollectionHasItemsConverter"/>
</Window.Resources>

Window.Resources

public class CollectionHasItemsConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return (bool)value;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

转换器

Button

我的收藏品的基础（空或不）我想启用/禁用我的<Button Name="btnDeleteAll" Click="btnDeleteAll_Click" IsEnabled="{Binding Path=(caps.HasItems),Converter={StaticResource CollectionHasItemsConverter}}">：

error

我得到了这个{{1}}：

XamlParseException：类型引用找不到命名的类型＆＃39; {LabelEncoder}帽＆＃39;

Answer 1

我看不到您将'data': 'indoor_3D_map_example.geojson'与DataContext属性相关联的位置。

确保您拥有公共属性，因为WPF引擎未在您的类中运行，并且无法访问caps变量。请尝试以下方法：

private WiresharkFiles caps;

带有相应的

private WiresharkFiles caps;
public WiresharkFiles Files { get { return caps; } }

然后您的XAML将绑定到文件，如下所示

public MainWindow()
{
    InitializeComponent(); 
    caps = new WiresharkFiles();
    DataContext = Files;
}

更新您需要了解实现和绑定按钮的命令，这将使它更好。 Look at this article for info on implementing and dealing with commands.

Answer 2

大写是一个私有变量：

private WiresharkFiles caps;

为了绑定，它必须是公共财产：

public WiresharkFiles caps {get;set;}

您还必须将窗口的datacontext设置为自身。类似的东西：

this.DataContext = this;

或
在你的窗口标签中：

 DataContext="{Binding RelativeSource={RelativeSource Self}}"

我不知道这与您的初始问题有什么关系，但您可以在绑定中使用点符号你可以绑定：

{Binding AnObservableCollection.Count}

您可以在数据触发器中将其与0进行比较。如果要禁用它，可以使用按钮和绑定命令，然后使用icommand的canexecute，如果没有条目或任何逻辑，则返回false。

WPF：来自MainWindow.xaml的绑定属性导致错误

2 个答案: