我不明白为什么我的DataContext绑定在运行应用程序时不起作用。我也在使用设计时数据上下文,它是有效的。
以下是XAML的主要部分。这是来自MainWindow.xaml
<Window x:Class="Logs_Cleaner_WPF.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="600" Width="800" MinWidth="800" MinHeight="600" WindowStartupLocation="CenterScreen"
xmlns:data="clr-namespace:Logs_Cleaner_WPF.Data"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
DataContext="{Binding Items, RelativeSource={RelativeSource Self}}"
d:DataContext="{Binding Source={d:DesignInstance Type=data:DesignData, IsDesignTimeCreatable=True}}"
mc:Ignorable="d">
这也是来自MainWindow.xaml
<Window.Resources>
<HierarchicalDataTemplate x:Key="ChildDataTemplate">
<TextBlock Text="{Binding Path}"></TextBlock>
</HierarchicalDataTemplate>
<HierarchicalDataTemplate x:Key="RootDataTemplate" ItemsSource="{Binding DisplayFolders}" ItemTemplate="{StaticResource ChildDataTemplate}">
<TextBlock Text="{Binding Path}"></TextBlock>
</HierarchicalDataTemplate>
</Window.Resources>
这是主TreeView。我需要在这里展示所有东西。
<TreeView DataContext="{Binding}" ItemsSource="{Binding Items}" x:Name="TreeView" Grid.Row="1" VerticalContentAlignment="Top" Margin="10,5" ItemTemplate="{StaticResource RootDataTemplate}">
</TreeView>
这是C#代码。这来自MainWindow.xaml.cs,命名空间为Logs_Cleaner_WPF
public partial class MainWindow : Window
{
public static ObservableCollection<DisplayItem> Items { get; set; }
}
显示项目:
public abstract class DisplayItem : INotifyPropertyChanged
{
private string _path;
public virtual string Path
{
get { return _path; }
set
{
_path = value;
OnPropertyChanged();
}
}
private long _size;
public long Size {
get { return _size; }
set
{
_size = value;
OnPropertyChanged();
}
}
private bool _checked;
public bool Checked
{
get { return _checked; }
set
{
_checked = value;
OnPropertyChanged();
}
}
public override string ToString()
{
return Path;
}
public event PropertyChangedEventHandler PropertyChanged;
[NotifyPropertyChangedInvocator]
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
var handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
}
由于之前的声明,您的DataContext
已经是Items
集合了!
DataContext="{Binding Items, RelativeSource={RelativeSource Self}}"
所以与ItemsSource
的结合应该只是{Binding }
<TreeView ItemsSource="{Binding }" x:Name="TreeView" ... />
在您的情况下,它又是{Binding Items}
,所以它试图绑定到不存在的Items.Items
。
我认为最好按照@NETscape的建议,以适当的方式重写它。我要实现MVVM。