Xamarin形式。 单击按钮后从ViewModel加载View

Question

如何才能做到这一点？ 我已经能够使用xaml来实现它，就像这样。 我将如何使用ViewModel模式执行此操作？

View.xaml

<Button Margin="50,0,20,20" FontSize="Large" Text="Test" Clicked="Button_Clicked">
                </Button>

View.cs

private void Button_Clicked(object sender, EventArgs e)
{
    Get_LessonViewAsync();            
}

private async void Get_LessonViewAsync()
{
    var view = new LessonView();
    await Navigation.PushModalAsync(view);
}

Answer 1

在xaml中，您可以使用Command属性进行绑定：

<Button Margin="50,0,20,20" FontSize="Large" Text="Test" Command="{Binding ButtonCommand}"></Button>

在您的ViewModel中：

public ICommand ButtonCommand { get; private set; }
public ICommand GoLeftCommand { get; private set; }     
public ICommand GoRightCommand { get; private set; }     

public DemoViewModel ()
{
    ...
    ButtonCommand = new Command (() => {
            var view = new LessonView();
            await Navigation.PushModalAsync(view);
        });
    GoLeftCommand = new Command (() => {
            var view = new LeftView();
            await Navigation.PushModalAsync(view);
        });
    GoRightCommand = new Command (() => {
            var view = new RightView();
            await Navigation.PushModalAsync(view);
        });
}

摘录自：David Britch的https://blog.xamarin.com/simplifying-events-with-commanding/