我似乎有一个简单的数据绑定问题,但找不到正确的方法来解决。有一个TabControl
定义两个DataTemplate
,一个用于标签标题,一个用于标签内容。
内容模板包含一个ItemsControl
。ItemsControl尝试绑定到动态创建的ViewModel
(ConnectionInfoVM)。
当我显示UI时,绑定只是失败,但是关于它的输出中没有错误消息。
我必须如何设置DataContext和绑定,以便绑定起作用并实际显示DataBuffer?任何帮助,不胜感激。
ConnectionsControl:
<UserControl x:Class="XXXViewer.Views.ConnectionsControl"
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:viewModels="clr-namespace:XXXViewer.ViewModels"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<TabControl Grid.Row="0" Name="TabDynamic" SelectionChanged="tabDynamic_SelectionChanged">
<TabControl.Resources>
<DataTemplate x:Key="TabHeader" DataType="TabItem">
<DockPanel>
<TextBlock Text="{Binding RelativeSource={RelativeSource AncestorType={x:Type TabItem}}, Path=Header}" />
<Button Name="btnDelete" DockPanel.Dock="Right" Margin="5,0,0,0" Padding="0" Click="btnTabDelete_Click" CommandParameter="{Binding RelativeSource={RelativeSource AncestorType={x:Type TabItem}}, Path=Name}">
<Image Source="{DynamicResource DeleteImg}" Height="11" Width="11"></Image>
</Button>
</DockPanel>
</DataTemplate>
<DataTemplate x:Key="TabContent" DataType="viewModels:ConnectionInfoVM">
<StackPanel>
<ScrollViewer Name="Scroller" Background="Black">
<StackPanel>
<TextBlock Text="This line gets printed" Foreground="White" FontFamily="Consolas"/>
<ItemsControl Name="ItemCtrl" ItemsSource="{Binding DataBuffer}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Path=.}" Foreground="White" FontFamily="Consolas"/>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</StackPanel>
</ScrollViewer>
</StackPanel>
</DataTemplate>
</TabControl.Resources>
</TabControl>
</Grid>
</UserControl>
Connections后面的控制代码:
namespace XXXViewer.Views
{
public partial class ConnectionsControl : UserControl
{
private readonly ObservableCollection<TabItem> _tabItems = new ObservableCollection<TabItem>();
public ConnectionsControl()
{
InitializeComponent();
// bindings
TabDynamic.ItemsSource = _tabItems;
TabDynamic.DataContext = this;
}
// assume this gets called
private void AddTabItem(ConnectionInfoVM ci)
{
DataTemplate headerTemplate = TabDynamic.FindResource("TabHeader") as DataTemplate;
DataTemplate contentTemplate = TabDynamic.FindResource("TabContent") as DataTemplate;
// create new tab item
TabItem tab = new TabItem
{
Header = $"Tab {ci.ConnectionID}",
Name = $"T{ci.ConnectionID}",
HeaderTemplate = headerTemplate,
ContentTemplate = contentTemplate,
DataContext = ci
};
_tabItems.Insert(0, tab);
// set the new tab as active tab
TabDynamic.SelectedItem = tab;
}
}
}
ConnectionInfoVM:
namespace XXXViewer.ViewModels
{
public class ConnectionInfoVM : ViewModelBase
{
private readonly ObservableQueue<string> _dataBuffer = new ObservableQueue<string>();
public ObservableQueue<string> DataBuffer => _dataBuffer;
}
}
创建的选项卡的屏幕快照:结果选项卡
您设置了ContentTemplate但未设置Content,因此ContentTemplate永远不会应用,因为只有在设置Content时才应用ContentTemplate。而不是DataContext = ci
写Content = ci
。
顺便说一句,它DataContext = ci
是无用的,因为DataContext已经隐式地是应用了DataTemplate的对象。
编辑
使用WPF时,请使用和滥用其核心功能:绑定。
我将如何编写您的代码(如果我不使用完整的MVVM兼容代码):
您的XAML:
<TabControl Grid.Row="0" Name="TabDynamic"
ItemsSource="{Binding TabItems, Mode=OneWay}"
SelectionChanged="tabDynamic_SelectionChanged">
<TabControl.Resources>
<DataTemplate x:Key="TabHeader" DataType="TabItem">
<DockPanel>
<TextBlock Text="{Binding RelativeSource={RelativeSource AncestorType={x:Type TabItem}}, Path=Header}" />
<Button Name="btnDelete" DockPanel.Dock="Right" Margin="5,0,0,0" Padding="0" Click="btnTabDelete_Click" CommandParameter="{Binding RelativeSource={RelativeSource AncestorType={x:Type TabItem}}, Path=Name}">
<Image Source="{DynamicResource DeleteImg}" Height="11" Width="11"></Image>
</Button>
</DockPanel>
</DataTemplate>
</TabControl.Resources>
<TabControl.ItemTemplate>
<DataTemplate DataType="viewModels:ConnectionInfoVM">
<TabItem Header="{Binding ConnectionID, Mode=OneWay}"
Name="{Binding ConnectionID, Mode=OneWay}"
HeaderTemplate="{StaticResources TabHeader}">
<StackPanel>
<ScrollViewer Name="Scroller" Background="Black">
<StackPanel>
<TextBlock Text="This line gets printed" Foreground="White" FontFamily="Consolas"/>
<ItemsControl Name="ItemCtrl" ItemsSource="{Binding DataBuffer}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Path=.}" Foreground="White" FontFamily="Consolas"/>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</StackPanel>
</ScrollViewer>
</StackPanel>
</TabItem>
</DataTemplate>
</TabControl.ItemTemplate>
</TabControl>
您的cs代码变得更加简单:
namespace XXXViewer.Views
{
public partial class ConnectionsControl : UserControl
{
private readonly ObservableCollection<ConnectionInfoVM> _tabItems = new ObservableCollection<ConnectionInfoVM>();
public ObservableCollection<ConnectionInfoVM> TabItems {get {return _tabItems;}}
public ConnectionsControl()
{
InitializeComponent();
// bindings
//TabDynamic.ItemsSource = _tabItems;
TabDynamic.DataContext = this;
}
// assume this gets called
private void AddTabItem(ConnectionInfoVM ci)
{
TabItems.Add(ci);
}
}
}
我在重新阅读代码时注意到,您可能对代码隐藏中的绑定感到困惑。
您的代码TabDynamic.ItemsSource = _tabItems;
不是绑定,它只会设置一次。
无论如何,我建议您阅读一些有关MVVM的知识。TabItems应该在ViewModel类中,而不是在代码隐藏中。
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