mvvmlight与icommand备忘

先建一个实现了ICommand接口的类

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

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

        public event EventHandler CanExecuteChanged
        {
            add
            {
                CommandManager.RequerySuggested += value;
            }
            remove
            {
                CommandManager.RequerySuggested -= value;
            }
        }

        public bool CanExecute(object parameter)
        {
            return _canExecute(parameter);
        }

        public void Execute(object parameter)
        {
            _execute(parameter);
        }
    }

在viewmodel中添加

void UpdateExecute()
        {
            Console.WriteLine("ICommandExecute");
        }
        bool CanUpdateExecute()
        {
            return true;
        }

        private ICommand _doSomething;

        public ICommand DoSomething
        {
            get
            {
                if (_doSomething == null)
                {
                    _doSomething = new RelayCommand(p => this.UpdateExecute(), p => this.CanUpdateExecute());
                }
                return _doSomething;
            }
        }

在xaml中用Command来绑定 假设我们用的是RadioButton

<RadioButton Content="{Binding Content}" IsChecked="{Binding IsCheck}" GroupName="RadioButtons" 
Command="{Binding DataContext.DoSomething,RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=StackPanel}}"></RadioButton>

注意：

Binding DataContext.DoSomething

这里要用DataContext. 然后要设置一下RelativeSource 不然找不到这个方法会输出错误信息