WPF SimpleCommand可能与泛型？

Question

我正在使用此代码来创建一个简单的命令:

public class SimpleCommand : ICommand
{
    public Predicate<object> CanExecuteDelegate { get; set; }
    public Action<object> ExecuteDelegate { get; set; }

    #region ICommand Members

    public bool CanExecute(object parameter)
    {
        if (CanExecuteDelegate != null)
            return CanExecuteDelegate(parameter);
        return true;// if there is no can execute default to true
    }

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

    public void Execute(object parameter)
    {
        if (ExecuteDelegate != null)
            ExecuteDelegate(parameter);
    }

    #endregion
}

我没写这个.但我喜欢使用它.当我使用它时,它最终会像这样:

// This is the value that gets set to the command in the UI
public SimpleCommand DoSomethingCommand { get; set; }


public DoSomethingCommandConstructor()
{
    DoSomethingCommand = new SimpleCommand
                        {
                            ExecuteDelegate = x => RunCommand(x)
                        };
}

private void RunCommand(object o)
{
    // Run the command.
}

唯一的问题是RunCommand的参数是一个对象.我想我被仿制药宠坏了.我总是希望IDE /编译器只知道我正在使用的类型是什么.

是否可以更改此SimpleCommand类以使用泛型实现？

Answer 1

当然.是否会指向Prism的实现,但CodePlex源选项卡似乎无法正常工作.它看起来像:

public class SimpleCommand<T> : ICommand
{
    public Predicate<T> CanExecuteDelegate { get; set; }
    public Action<T> ExecuteDelegate { get; set; }

    #region ICommand Members

    public bool CanExecute(object parameter)
    {
        if (CanExecuteDelegate != null)
            return CanExecuteDelegate((T)parameter);
        return true;// if there is no can execute default to true
    }

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

    public void Execute(object parameter)
    {
        if (ExecuteDelegate != null)
            ExecuteDelegate((T)parameter);
    }

    #endregion
}

顺便提一下,你在问题中使用SimpleCommand有点迂回.而不是这个:

DoSomethingCommand = new SimpleCommand
                    {
                        ExecuteDelegate = x => RunCommand(x)
                    };

你可能只有:

DoSomethingCommand = new SimpleCommand
                    {
                        ExecuteDelegate = this.RunCommand
                    };

指定lambda实际上只有在你像这样进行内联工作时才有用:

DoSomethingCommand = new SimpleCommand
                    {
                        ExecuteDelegate = o => this.SelectedItem = o,
                        CanExecuteDelegate = o => o != null
                    };