Handles CheckBox Indeterminate events when a CheckBox changes to a indeterminate state. : CheckBox Event « Windows Presentation Foundation « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. Windows Presentation Foundation
3. CheckBox Event

<Window x:Class="WpfApplication1.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="WPF" Height="250" Width="300">
    <StackPanel Name="panel">
        <CheckBox 
                  Content="Third CheckBox (Tri-State Enabled)" 
                  Indeterminate="CheckBox_Indeterminate"  IsChecked="True" 
                  IsThreeState="True" Margin="2" Name="checkbox3" 
                  />
        <Button Content="Get Selected" Margin="5" MaxWidth="100" 
                Click="Button_Click" />
        <TextBlock FontWeight="Bold" Text="Selected CheckBoxes:" />
        <ListBox Margin="5" MinHeight="2cm" Name="listbox" />
    </StackPanel>
</Window>
//File:Window.xaml.cs
using System.Linq;
using System.Windows;
using System.Windows.Controls;

namespace WpfApplication1
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
        }
        private void Button_Click(object sender, RoutedEventArgs e)
        {
            listbox.Items.Clear();
            foreach (CheckBox checkbox in panel.Children.OfType<CheckBox>().Where( cb => cb.IsChecked == true))
            {
                listbox.Items.Add(checkbox.Name);
            }
        }
        private void CheckBox_Indeterminate(object sender, RoutedEventArgs e)
        {
            if (!IsInitialized) return;

            CheckBox checkbox = e.OriginalSource as CheckBox;

            if (checkbox != null)
            {
                MessageBox.Show(checkbox.Name + " is indeterminate.", Title);
            }
        }

    }
}

24.18.CheckBox Event
	24.18.1.	Create a CheckBox and link event handler
	24.18.2.	Handles CheckBox Indeterminate events when a CheckBox changes to a indeterminate state.
	24.18.3.	Handle CheckBox Unchecked events
	24.18.4.	Handle CheckBox checked events
	24.18.5.	Use Linq to get checked CheckBox
	24.18.6.	Check the CheckBox based on key pressed states