[WPF]MVVM Sample

MVVM_Basics.zip

0.47MB

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ViewModelBase

public class ViewModelBase : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler? PropertyChanged;

        protected virtual void OnPropertyChanged([CallerMemberName] string? propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }

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CommandBase

public abstract class CommandBase : ICommand
    {
        public event EventHandler? CanExecuteChanged;

        public virtual bool CanExecute(object? parameter)
        {
            return true;
        }
        public abstract void Execute(object? parameter);
        protected void OnCanExecuteChanged()
        {
            CanExecuteChanged?.Invoke(this, new EventArgs());
        }
    }

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RelayCommand

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

        public RelayCommand(Action<object> execute) : this(execute, null) { }
        public RelayCommand(Action<object> execute, Predicate<object> canExecute)
        {
            _canExecute = canExecute;
            _execute = execute ?? throw new ArgumentNullException("execute");
        }

        public override bool CanExecute(object? parameter)
        {
            return _canExecute == null || _canExecute(parameter);
        }
        public override void Execute(object? parameter)
        {
            _execute(parameter);
        }
    }

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