【发布时间】：2018-07-10 15:35:49
【问题描述】：
我是 WPF 初学者，遇到了很多问题。
我做了一个TreeView 程序，但我不知道如何选择一个节点。我想添加一个add 和一个delete 按钮。所以应该不难。
我将不胜感激。提前谢谢你。
这是视图模型。它是MVVM模式的View。
using System;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Windows;
using System.Windows.Input;
namespace TreeViewTest2
{
public class MainViewModel : INotifyPropertyChanged
{
int i = 0;
public ObservableCollection<A> a { get; set; }
public MainViewModel()
{
a = new ObservableCollection<A>();
}
public ICommand addADelegate;
public ICommand AddADelegate
{
get { return addADelegate = new delegateCommand(addA); }
}
public ICommand addBDelegate;
public ICommand AddBDelegate
{
get { return addBDelegate = new delegateCommand(addB); }
}
public ICommand addCDelegate;
public ICommand AddCDelegate
{
get { return addCDelegate = new delegateCommand(addC); }
}
public ICommand deleteADelegate;
public ICommand DeleteADelegate
{
get { return deleteADelegate = new delegateCommand(deleteA); }
}
public ICommand deleteBDelegate;
public ICommand DeleteBDelegate
{
get { return deleteBDelegate = new delegateCommand(deleteB); }
}
public ICommand deleteCDelegate;
public ICommand DeleteCDelegate
{
get { return deleteCDelegate = new delegateCommand(deleteC); }
}
public void addA()
{
a.Add(new A { Name = "A added " + (i++) });
}
public void addB()
{
if (a.Count == 0)
{
MessageBox.Show(" Add A First");
}
else
a[0].b.Add(new B { Name = "B added" });
}
public void addC()
{
if ( a.Count == 0 || a[0].b.Count==0 )
{
MessageBox.Show(" Add B First");
}
else
a[0].b[0].c.Add(new C { Name = "C added" });
}
public void deleteA()
{
if (a.Count == 0)
MessageBox.Show("Error");
else
a.RemoveAt(0);
}
public void deleteB()
{
if (a.Count == 0 || a[0].b.Count == 0)
MessageBox.Show("Error");
else
a[0].b.RemoveAt(0);
}
public void deleteC()
{
if (a.Count == 0 || a[0].b.Count == 0 || a[0].b[0].c.Count == 0)
MessageBox.Show("Error");
else
a[0].b[0].c.RemoveAt(0);
}
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
#region A
public class A
{
public string Name { get; set; }
public ObservableCollection<B> b { get; set; }
public A()
{
b = new ObservableCollection<B>();
}
}
#endregion
#region B
public class B
{
public string Name { get; set; }
public ObservableCollection<C> c { get; set; }
public B()
{
c = new ObservableCollection<C>();
}
}
#endregion
#region C
public class C
{
public string Name { get; set; }
}
#endregion
#region delegateCommand
public class delegateCommand : ICommand
{
private Action execute;
public delegateCommand(Action execute)
{
this.execute = execute;
}
public event EventHandler CanExecuteChanged;
public bool CanExecute(object parameter)
{
return true;
}
public void Execute(object parameter)
{
execute?.Invoke();
}
}
#endregion
}
这是 XAML：
<Window x:Class="TreeViewTest2.MainWindow"
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:local="clr-namespace:TreeViewTest2"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800">
<Window.DataContext>
<local:MainViewModel/>
</Window.DataContext>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="6*"/>
<ColumnDefinition Width="2*"/>
</Grid.ColumnDefinitions>
<TreeView Grid.Column="0" ItemsSource="{Binding a}" >
<TreeView.Resources>
<HierarchicalDataTemplate DataType="{x:Type local:A}" ItemsSource="{Binding b}" >
<TextBlock Text="{Binding Name}"/>
</HierarchicalDataTemplate>
<HierarchicalDataTemplate DataType="{x:Type local:B}" ItemsSource="{Binding c}" >
<TextBlock Text="{Binding Name}"/>
</HierarchicalDataTemplate>
<DataTemplate DataType="{x:Type local:C}" >
<TextBlock Text="{Binding Name}" />
</DataTemplate>
</TreeView.Resources>
</TreeView>
<StackPanel Orientation="Vertical" Grid.Column="1" >
<Button Content="Add A" Command="{Binding AddADelegate}" />
<Button Content="Add B" Command="{Binding AddBDelegate}"/>
<Button Content="Add C " Command="{Binding AddCDelegate}"/>
<Button Content="Delete A" Command="{Binding DeleteADelegate}"/>
<Button Content="Delete B" Command="{Binding DeleteBDelegate}"/>
<Button Content="Delete C" Command="{Binding DeleteCDelegate}"/>
</StackPanel>
</Grid>
</Window>
【问题讨论】：