Question

简单地说，我有一个有多种视图的棱镜模块。

其中一个是带有网格的用户控件，我需要在此视图处于活动状态时重新加载其datacontext。

我知道我必须使用IActiveAware界面，但我无法弄清楚如何......

修改

MyUserControl.xaml

<UserControl x:Class="[...]
             mc:Ignorable="d">

    <UserControl.Resources>
        <dc:MyViewModel x:Key="MyViewModel" />
    </UserControl.Resources>

    <Grid DataContext="{StaticResource MyViewModel}">
        <Grid.RowDefinitions>
    [...]

MyUserControl.xaml.cs

public partial class MyUserControl: UserControl, IActiveAware
{
    public MyUserControl(IRegionManager _regionManager)
    {
        regionManager = _regionManager;
        InitializeComponent();         
    }

    public event EventHandler<EventArgs> Activated;

    public event EventHandler<EventArgs> Deactivated;

    private bool _IsActive;
    public bool IsActive
    {
        get
        {
            return _IsActive;
        }
        set
        {
            _IsActive = value;
            IActiveAware vmAware = DataContext as IActiveAware;
            if (vmAware != null)
                vmAware.IsActive = value;

        }
    }
    public event EventHandler IsActiveChanged = delegate { };
[...]

MyViewModel.cs

public class MyViewModel: IActiveAware
{
    private bool isActive { get; set; }
    public bool IsActive
    {
        get
        {
            return isActive;
        }
        set
        {
            isActive = value;
            LoadData();
            IsActiveChanged(this, EventArgs.Empty);
        }
    }

    public event EventHandler IsActiveChanged = delegate { };
[...]

Answer 1

只需在视图模型上实现界面即可。你也需要实现事件处理程序，但我已经离开了这个例子。您可以在Brian Noyes's blog上看到完整示例。

public class ViewModel : IActiveAware
{
    private bool _isActive;

    public bool IsActive
    {
        get { return _isActive; }
        set
        {
             _isActive = value;

             // Do Other Stuff e.g.
             LoadData();
        }
    }

    private void LoadData()
    {
         .....
    }
}

Prism查看它正在激活的视图模型，并确定它是否实现IActiveAware，如果是，则设置IsActive，以便您可以创建视图模型，从而看，做点什么。

如何激活视图？

1 个答案: