Silverlight MVVM visualstatemanager和focus

使用Silverlight 4

我的控件有两种可视状态。我想在状态改变时将焦点从一个文本框更改为另一个文本框

使用MVVM实现这一点的最佳方法是什么

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我希望用visualstatemanager来做这件事或者做一个行为。。。但是我还没有想出一个办法。

在文本框之间更改焦点是视图特定的代码，所以我认为应该在视图后面的代码中完成。有些人建议根本没有代码，但我认为这有点夸张

至于如何从ViewModel触发它，我将执行以下操作：

class MyView : UserControl {

    // gets or sets the viewmodel attached to the view
    public MyViewModel ViewModel {
        get {...}
        set {
           // ... whatever method you're using for attaching the
           // viewmodel to a view
           myViewModel = value;
           myViewModel.PropertyChanged += ViewModel_PropertyChanged;
    }

    private void ViewModel_PropertyChanged(object sender, PropertyChangedEventArgs e) {
        if (e.PropertyName == "State") {
            VisualStateManager.GoToState(this, ViewModel.State, true);
            if (ViewModel.State == "FirstState") {
                textBox1.Focus();
            }
            else if (ViewModel.State == "SecondState") {
                textBox2.Focus();
            }
        }
    }

}

class MyViewModel : INotifyPropertyChanged {

    // gets the current state of the viewmodel
    public string State {
        get { ... }
        private set { ... } // with PropertyChanged event
    }

    // replace this method with whatever triggers your
    // state change, such as a command handler
    public void ToggleState() {
        if (State == "SecondState") { State = "FirstState"; }
        else { State = "SecondState"; }
    }

}

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在文本框之间更改焦点是视图特定的代码，所以我认为应该在视图的代码后面完成。有些人建议根本没有代码，但我认为这有点夸张

至于如何从ViewModel触发它，我将执行以下操作：

class MyView : UserControl {

    // gets or sets the viewmodel attached to the view
    public MyViewModel ViewModel {
        get {...}
        set {
           // ... whatever method you're using for attaching the
           // viewmodel to a view
           myViewModel = value;
           myViewModel.PropertyChanged += ViewModel_PropertyChanged;
    }

    private void ViewModel_PropertyChanged(object sender, PropertyChangedEventArgs e) {
        if (e.PropertyName == "State") {
            VisualStateManager.GoToState(this, ViewModel.State, true);
            if (ViewModel.State == "FirstState") {
                textBox1.Focus();
            }
            else if (ViewModel.State == "SecondState") {
                textBox2.Focus();
            }
        }
    }

}

class MyViewModel : INotifyPropertyChanged {

    // gets the current state of the viewmodel
    public string State {
        get { ... }
        private set { ... } // with PropertyChanged event
    }

    // replace this method with whatever triggers your
    // state change, such as a command handler
    public void ToggleState() {
        if (State == "SecondState") { State = "FirstState"; }
        else { State = "SecondState"; }
    }

}

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如果我是你，我会创建一个FocusBehavior，使用FocusBehavior.IsFocused属性，将该行为添加到控件上，并在VSM状态集IsFocused=True中

如果我是你，我会创建一个FocusBehavior，使用FocusBehavior.IsFocused属性，将该行为添加到控件上，并在VSM状态集IsFocused=True中

与JustinAngle的答案非常相似，但我认为这是Silverlight特有的解决方案，值得一提。基本上，Jeremy Likess创建了一个虚拟控件，他称之为FocusHelper，其行为非常类似于FocusBehavior。

这与JustinAngle的答案非常相似，但我认为这是一个Silverlight特有的解决方案，值得一提。基本上Jeremy Likess创建了一个虚拟控件，他称之为FocusHelper，其行为非常类似于FocusBehavior