I have a List
of Lists
and display it with nested ListBoxes
:
MainWindow.xaml.cs
using System.Collections.Generic;
namespace WPF_Sandbox
{
public partial class MainWindow
{
public IEnumerable<IEnumerable<string>> ListOfStringLists { get; set; } = new[] { new[] { "a", "b" }, new[] { "c", "d" } };
public MainWindow()
{
InitializeComponent();
DoSomethingButton.Click += (sender, e) =>
{
// do something with all selected items
};
}
}
}
MainWindow.xaml
<Window x:Class="WPF_Sandbox.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow"
x:Name="ThisControl">
<StackPanel>
<ListBox ItemsSource="{Binding ListOfStringLists, ElementName=ThisControl}">
<ListBox.ItemTemplate>
<ItemContainerTemplate>
<ListBox ItemsSource="{Binding}" SelectionMode="Multiple">
<ListBox.ItemTemplate>
<ItemContainerTemplate>
<TextBlock Text="{Binding}" />
</ItemContainerTemplate>
</ListBox.ItemTemplate>
</ListBox>
</ItemContainerTemplate>
</ListBox.ItemTemplate>
</ListBox>
<Button Name="DoSomethingButton" Content="DoSomething" />
</StackPanel>
</Window>
How can I get all selected items across all ListBoxes
?
I found a few solutions getting one selected item but could not figure out how to do applie those in my scenario.
I have an idea on how to do this by wrapping the string
arrays but I would prefer not doing this.
The easiest way would be to iterate through the items in the ListBox
es:
private void DoSomethingButton_Click(object sender, RoutedEventArgs e)
{
List<string> selectedStrings = new List<string>();
foreach (IEnumerable<string> array in outerListBox.Items.OfType<IEnumerable<string>>())
{
ListBoxItem lbi = outerListBox.ItemContainerGenerator.ContainerFromItem(array) as ListBoxItem;
if (lbi != null)
{
ListBox innerListBox = GetChildOfType<ListBox>(lbi);
if (innerListBox != null)
{
foreach (string selectedString in innerListBox.SelectedItems.OfType<string>())
selectedStrings.Add(selectedString);
}
}
}
}
private static T GetChildOfType<T>(DependencyObject depObj) where T : DependencyObject
{
if (depObj == null)
return null;
for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
{
var child = VisualTreeHelper.GetChild(depObj, i);
var result = (child as T) ?? GetChildOfType<T>(child);
if (result != null)
return result;
}
return null;
}
Note that the ListBoxItem
may be virtualized away if you have a lot of inner IEnumerable<string>
. You will then have to force the generation of the containers or disable UI virtualization:
WPF ListView virtualization. How to disable ListView virtualization?
This may affect the performance negatively so if this is an issue you should probably consider binding to an IEnumerable<YourType>
and bind the SelectedItems
property of the inner ListBox
to a property of a YourType
using a behaviour.
Since the SelectedItems
property of a ListBox
is read-only you can't bind to it directly: https://blog.magnusmontin.net/2014/01/30/wpf-using-behaviours-to-bind-to-readonly-properties-in-mvvm/ .
I would just add an event handler to the inner ListBox
like so if not doing things the MVVM way:
<ListBox ItemsSource="{Binding}" SelectionMode="Multiple" SelectionChanged="ListBox_SelectionChanged">
Then in your code behind implement the ListBox_SelectionChanged
like so:
public List<string> FlatStringList = new List<string>();
private void ListBox_SelectionChanged(object sender,System.Windows.Controls.SelectionChangedEventArgs e)
{
FlatStringList.AddRange(e.AddedItems.Cast<string>());
foreach(string s in e.RemovedItems)
{
FlatStringList.Remove(s);
}
}
This is assuming you don't mind storing the selected strings in a flat list. Then you could implement your DoSomething
button click event handler to do something with the FlatStringList
. Hope that helps.
Why don't you create a wrapper (as you said):
public class MyString : INotifyPropertyChanged
{
public MyString(string value) { Value = value; }
string _value;
public string Value { get { return _value; } set { _value = value; RaisePropertyChanged("Value"); } }
bool _isSelected;
public bool IsSelected { get { return _isSelected; } set { _isSelected = value; RaisePropertyChanged("IsSelected"); } }
public event PropertyChangedEventHandler PropertyChanged;
void RaisePropertyChanged(string propname)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propname));
}
}
Bind the IsSelected property of the ListBoxItems:
<StackPanel>
<ListBox ItemsSource="{Binding ListOfStringLists, ElementName=ThisControl}">
<ListBox.ItemTemplate>
<ItemContainerTemplate>
<ListBox ItemsSource="{Binding}" SelectionMode="Multiple">
<ListBox.ItemTemplate>
<ItemContainerTemplate>
<TextBlock Text="{Binding Value}" />
</ItemContainerTemplate>
</ListBox.ItemTemplate>
<ListBox.ItemContainerStyle>
<Style TargetType="{x:Type ListBoxItem}">
<Setter Property="IsSelected" Value="{Binding IsSelected}"/>
</Style>
</ListBox.ItemContainerStyle>
</ListBox>
</ItemContainerTemplate>
</ListBox.ItemTemplate>
</ListBox>
<Button Name="DoSomethingButton" Content="DoSomething" />
</StackPanel>
and you are already done:
public IEnumerable<IEnumerable<MyString>> ListOfStringLists { get; set; } = new[] { new[] { new MyString("a"), new MyString("b") { IsSelected = true } }, new[] { new MyString("c"), new MyString("d") } };
public MainWindow()
{
this.InitializeComponent();
DoSomethingButton.Click += (sender, e) =>
{
foreach (var i in ListOfStringLists)
foreach (var j in i)
{
if (j.IsSelected)
{
// ....
}
}
};
}
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