Can someone point to an example of how to programmatically create & use Radio Buttons in C# WPF?
So basically how to (a) create them programmatically, and (b) how to catch triggers when the value changes, (c) how to pick up results at a given time.
Will be interested to see too if the answer will be based on use of a Binding approach too. If data binding is the easiest way to go then an example of this would be great. Else if data binding isn't necessary the best/easiest way to go then a non-data-binding based example would be good.
Notes:
Note that the parent node I have currently is StackPanel, so an aspect of the question is how to add multiple RadioButtons to a StackPanelI guess.
Should point out that I won't know how many radio buttons there will be at compile time, nor what the text will be this will be discovered at run time.
It is a WPF application (i.e. desktop, not a web app)
Normally, we use RadioButtons to present an Enum data type to the user. And what we usually do is use an ItemsControl to present a group of RadioButtons, with each one bound to a ViewModel.
Below is a sample application I just wrote that demonstrates how RadioButtons could be used in two ways: the first is somewhat of a direct approach (and this may answer your questions above), and the second one uses an MVVM approach.
BTW, this is just something I wrote quickly (yeah, I got a lot of time in my hands) so I won't say that everything in here is the perfect way of doing things. But I hope you find this helpful:
XAML:
<Window x:Class="RadioButtonSample.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:RadioButtonSample"
Title="MainWindow" Height="350" Width="525">
<StackPanel>
<StackPanel x:Name="sp"/>
<Button x:Name="showChoice" Click="showChoice_Click">Show Choice</Button>
<StackPanel x:Name="sp2">
<StackPanel.DataContext>
<local:ViewModel/>
</StackPanel.DataContext>
<ItemsControl x:Name="itemsControl" ItemsSource="{Binding Path=Choices}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<RadioButton IsChecked="{Binding Path=IsChecked}" Content="{Binding Path=Choice}" GroupName="ChoicesGroup"/>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
<Button x:Name="showChoice2" Click="showChoice2_Click">Show Choice2</Button>
</StackPanel>
</StackPanel>
Code-behind:
using System;
using System.Collections;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.ComponentModel;
using System.Collections.Generic;
namespace RadioButtonSample
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
//Initialize the first group of radio buttons and add them to the panel.
foreach (object obj in Enum.GetValues(typeof(ChoicesEnum)))
{
RadioButton rb = new RadioButton() { Content = obj, };
sp.Children.Add(rb);
rb.Checked += new RoutedEventHandler(rb_Checked);
rb.Unchecked += new RoutedEventHandler(rb_Unchecked);
}
}
void rb_Unchecked(object sender, RoutedEventArgs e)
{
Console.Write((sender as RadioButton).Content.ToString() + " checked.");
}
void rb_Checked(object sender, RoutedEventArgs e)
{
Console.Write((sender as RadioButton).Content.ToString() + " unchecked.");
}
private void showChoice_Click(object sender, RoutedEventArgs e)
{
foreach (RadioButton rb in sp.Children)
{
if (rb.IsChecked == true)
{
MessageBox.Show(rb.Content.ToString());
break;
}
}
}
private void showChoice2_Click(object sender, RoutedEventArgs e)
{
//Show selected choice in the ViewModel.
ChoiceVM selected = (sp2.DataContext as ViewModel).SelectedChoiceVM;
if (selected != null)
MessageBox.Show(selected.Choice.ToString());
}
}
//Test Enum
public enum ChoicesEnum
{
Choice1,
Choice2,
Choice3,
}
//ViewModel for a single Choice
public class ChoiceVM : INotifyPropertyChanged
{
public ChoicesEnum Choice { get; private set; }
public ChoiceVM(ChoicesEnum choice)
{
this.Choice = choice;
}
private bool isChecked;
public bool IsChecked
{
get { return this.isChecked; }
set
{
this.isChecked = value;
this.OnPropertyChanged("IsChecked");
}
}
#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propName)
{
if (this.PropertyChanged != null)
{
this.PropertyChanged(this, new PropertyChangedEventArgs(propName));
}
}
#endregion
}
//Sample ViewModel containing a list of choices
//and exposes a property showing the currently selected choice
public class ViewModel : INotifyPropertyChanged
{
public List<ChoiceVM> Choices { get; private set; }
public ViewModel()
{
this.Choices = new List<ChoiceVM>();
//wrap each choice in a ChoiceVM and add it to the list.
foreach (var choice in Enum.GetValues(typeof(ChoicesEnum)))
this.Choices.Add(new ChoiceVM((ChoicesEnum)choice));
}
public ChoiceVM SelectedChoiceVM
{
get
{
ChoiceVM selectedChoice = this.Choices.FirstOrDefault((c) => c.IsChecked == true);
return selectedChoice;
}
}
#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propName)
{
if (this.PropertyChanged != null)
{
this.PropertyChanged(this, new PropertyChangedEventArgs(propName));
}
}
#endregion
}
}
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