Question

最初我在代码后面有一个按钮事件。

private async void SomeCommand(object sender, RoutedEventArgs e)
{
    MySlider.Value = MySlider.Value - 1;

在我的XAML中。

 <Button Command="{Binding SomeCommand}">Do Something</Button>

现在我将使用MVVM。

public class MyViewModel : ViewModel
{
    private readonly ICommand someCommand;
    public MyViewModel()
    {
        this.someCommand = new DelegateCommand(this.DoSomething, this.CanDoSomething);
    }

    public ICommand SomeCommand
    {
        get { return this.someCommand; }
    }

    private void DoSomething(object state)
    {
        // do something here
    }

    private bool CanDoSomething(object state)
    {
       // return true/false here is enabled/disable button
    }
}

我不知道方法DoSomething中的代码是什么？

Answer 1

如果要使用MVVM方法，则应使用可绑定的属性Value。你的xaml看起来像

<Slider x:Name="MySlider" Value="{Binding Value}" />
<Button Command="{Binding SomeCommand}">Do Something</Button>

在ICommand中，您使用两个单独的方法来检查命令是否可以执行（CanDoSomething）并执行它（DoSomething）。

确保您的ViewModel实现INotifyPropertyChanged，如果Value发生更改，您必须提升public class MyViewModel : ViewModel { private readonly ICommand someCommand; public MyViewModel() { this.someCommand = new DelegateCommand(this.DoSomething, this.CanDoSomething); } public ICommand SomeCommand { get { return this.someCommand; } } private void DoSomething(object state) { Value = Value - 1; } private bool CanDoSomething(object state) { //something like boundaries check of slider values and async is running and so on } private int _value; public int Value { get { return _value; } set { if (_value != value) { _value = value; OnPropertyChanged(); //raise your propertyChanged event handler. } } } }。您的ViewModel应该看起来像

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更新MVVM中的滑块值

1 个答案: