WPF Radio Button Group Collision with Custom User Controls

Question

I instanciate the same UserControl twice. Both have Radiobuttons and share the GroupName. When I select one all others deselect even when they are part of a different UserControl Instance.

How can this GroupName Collision be avoided?

Here is a minimal example to illustrate the point:

Main xaml

<Window x:Class="RadioDemo.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <StackPanel>
        <UserControl x:Name="First"/>
        <UserControl x:Name="Second"/>
    </StackPanel>
</Window>

Main Codebehind

public MainWindow()
{
    InitializeComponent();
    Loaded += MainWindow_Loaded;
}

void MainWindow_Loaded(object sender, RoutedEventArgs e)
{
    First.Content = new MyRadio();
    Second.Content = new MyRadio();
}

MyRadio xaml

<UserControl x:Class="RadioDemo.MyRadio"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300">
    <StackPanel>
        <RadioButton GroupName="G" x:Name="RadioOne" Content="RadioOne"/>
        <RadioButton GroupName="G" x:Name="RadioTwo" Content="RadioTwo"/>
    </StackPanel>
</UserControl>

Answer 1

You can create group name value dynamically once user control is loaded.

XAML:

<StackPanel>
    <RadioButton GroupName="{Binding GroupNameValue}" x:Name="RadioOne" Content="RadioOne"/>
    <RadioButton GroupName="{Binding GroupNameValue}" x:Name="RadioTwo" Content="RadioTwo"/>
</StackPanel>

View-model:

private string groupNameValue = Guid.NewGuid().ToString();

public string GroupNameValue
{
    protected get { return this.groupNameValue; }
    set
    {
        this.SetProperty(ref this.groupNameValue, value);
    }
}

Where SetProperty is implementation of INotifyPropertyChanged .
Here I used Guid as guarantee of the uniqueness, but you can use whether you want.

With C# 6.0 code can be simplified:

private string groupNameValue = Guid.NewGuid().ToString();

public string GroupNameValue => this.groupNameValue;