WPF_Practice/PacticeSolution/AddressBook_MVVMSample/Command/DelegateCommand.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;

namespace AddressBook_MVVMSample.Command
{
    public class DelegateCommand : ICommand
    {
        private readonly Action<object> _execute;
        private readonly Predicate<object> _canExecute;

        public event EventHandler CanExecuteChanged;

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

        public DelegateCommand(Action<object> execute) : this(execute, null)
        {

        }

        public bool CanExecute(object parameter)
        {
            return _canExecute == null ? true : _canExecute(parameter);
        }

        public void Execute(object parameter)
        {
            _execute?.Invoke(parameter);
        }
    }
}