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Button Click Handler

Basic click event implementation for a Button control.

private void MyButton_Click(object sender, RoutedEventArgs e)
{
    // TODO: Add your code here
    MessageBox.Show("Button clicked!");
}

Data Binding Example

Binding a TextBox to a property in the ViewModel.

<TextBox Text="{Binding Path=UserName, UpdateSourceTrigger=PropertyChanged}" />

ObservableCollection Demo

Using ObservableCollection to auto-update UI lists.

public ObservableCollection<string> Items { get; set; } = new ObservableCollection<string>();

public MainWindow()
{
    InitializeComponent();
    DataContext = this;
    Items.Add("Item 1");
    Items.Add("Item 2");
}

RelayCommand Implementation

Simple ICommand implementation for MVVM commands.

public class RelayCommand : ICommand
{
    private readonly Action<object> _execute;
    private readonly Predicate<object> _canExecute;

    public RelayCommand(Action<object> execute, Predicate<object> canExecute = null)
    {
        _execute = execute;
        _canExecute = canExecute;
    }

    public bool CanExecute(object parameter) => _canExecute?.Invoke(parameter) ?? true;
    public void Execute(object parameter) => _execute(parameter);
    public event EventHandler CanExecuteChanged
    {
        add => CommandManager.RequerySuggested += value;
        remove => CommandManager.RequerySuggested -= value;
    }
}

Resource Dictionary Merge

Merge multiple resource dictionaries in App.xaml.

<Application.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="Themes/Light.xaml" />
            <ResourceDictionary Source="Styles/Controls.xaml" />
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</Application.Resources>