问题描述
最近几天我在努力.我找到了很多链接,但没有一个真正对我有帮助.我是WPF的初学者.我需要做的就是在嵌套ListView中到达SelectedItem属性.当然,外部ListView绑定有效.经过一些研究后,我尝试了一下但没有用,甚至我真的不明白为什么它不起作用:
I'm wrestling with these last few days. I found lots of links, but none of them really helped me. I'm quite a beginner in WPF. All I need is to reach SelectedItem property in nested ListView. Outter ListView binding works, of course.What I tried after some research and doesn't work, even I don't really understand why it dosnt work:
<Window x:Class="ListViewRef.View.ListViewWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:vm="clr-namespace:ListViewRef.ViewModel"
xmlns:local="clr-namespace:ListViewRef.View"
mc:Ignorable="d"
Title="Nested List Views" Height="450" Width="800">
<Window.DataContext>
<vm:MainVM/>
</Window.DataContext>
<StackPanel x:Name="Global">
<TextBlock Text="{Binding MainTitle}"/>
<ListView ItemsSource="{Binding Path=SourceCollection}"
SelectedItem="{Binding Path=OutterSelectedItem}"
>
<ListView.ItemTemplate>
<DataTemplate>
<StackPanel>
<TextBlock Text="{Binding Title}"/>
<TextBlock Text="Now second ListView:"/>
<ListView ItemsSource="{Binding Strings}"
SelectedItem="{Binding Path=NestedSelectedItem,
RelativeSource={RelativeSource AncestorType=vm:MainVM},
Mode=TwoWay,
UpdateSourceTrigger=PropertyChanged}"
></ListView>
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackPanel>
</Window>
和ViewModel:
And ViewModel:
using ListViewRef.Model;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Windows;
namespace ListViewRef.ViewModel
{
public class MainVM : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private string mainTitle;
public string MainTitle {
get { return mainTitle; }
set { mainTitle = value; OnPropertyChanged(nameof(MainTitle)); }
}
private string nestedSelectedItem;
public string NestedSelectedItem {
get { return nestedSelectedItem; }
set
{
nestedSelectedItem = value;
MessageBox.Show("NestedSelectedItem: " + nestedSelectedItem);
OnPropertyChanged(nameof(NestedSelectedItem));
}
}
private string outterSelectedItem;
public string OutterSelectedItem {
get { return outterSelectedItem; }
set
{
outterSelectedItem = value;
MessageBox.Show("OutterSelectedItem: " + OutterSelectedItem);
OnPropertyChanged(nameof(OutterSelectedItem));
}
}
public ObservableCollection<ClassWithObsList> SourceCollection { get; set; }
public MainVM()
{
MainTitle = "Title of the Grid";
SourceCollection = new ObservableCollection<ClassWithObsList> {
new ClassWithObsList("First Title", new ObservableCollection<string> { "First", "Second"}),
new ClassWithObsList("Second Title", new ObservableCollection<string> { "Third", "Fourth"}),
new ClassWithObsList("Third Title", new ObservableCollection<string> { "Fifth", "Sixth"}),
};
}
private void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
模型类:
using System;
using System.Collections.ObjectModel;
using System.ComponentModel;
namespace ListViewRef.Model
{
public class ClassWithObsList : INotifyPropertyChanged
{
private string title;
public string Title {
get { return title; }
set {
title = value;
OnPropertyChanged(nameof(Title));
}
}
public ObservableCollection<string> Strings { get; set; }
public event PropertyChangedEventHandler PropertyChanged;
public ClassWithObsList(string title, ObservableCollection<string> strings)
{
Title = title ?? throw new ArgumentNullException(nameof(title));
Strings = strings ?? throw new ArgumentNullException(nameof(strings));
}
private void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
推荐答案
在
SelectedItem="{Binding Path=NestedSelectedItem,
RelativeSource={RelativeSource AncestorType=vm:MainVM}, ...}
vm:MainVM
类型不是内部ListView的祖先类型,因为它不是可视树或逻辑树的一部分.
the type vm:MainVM
is not an ancestor type of the inner ListView, because it not part of a visual or logical tree.
AncestorType必须是一个UI元素,例如外部ListView.您将通过嵌套的属性Path通过其DataContext访问该属性:
The AncestorType must be a UI element, e.g. the outer ListView. You would access the property by a nested property Path via its DataContext:
SelectedItem="{Binding Path=DataContext.NestedSelectedItem,
RelativeSource={RelativeSource AncestorType=ListView}, ...}
请注意,由于您没有设置ListViews的 View
属性,因此也可以使用更简单的基类ListBox代替ListView:
As a note, since you are not setting the View
property of the ListViews, you could as well use the simpler base class ListBox instead of ListView:
<ListBox ItemsSource="{Binding Path=SourceCollection}"
SelectedItem="{Binding Path=OutterSelectedItem}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<TextBlock Text="{Binding Title}"/>
<TextBlock Text="Now second ListView:"/>
<ListBox ItemsSource="{Binding Strings}"
SelectedItem="{Binding Path=DataContext.NestedSelectedItem,
RelativeSource={RelativeSource AncestorType=ListBox},
Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
这篇关于如何在嵌套的ListView中到达SelectedItem的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!