绑定按钮' WP7 中 ViewModel 属性的样式

发布于 2024-11-30 13:43:22 字数 508 浏览 1 评论 0原文

我在音频记录视图中有一个播放按钮。

目前它被定义为：

<Button Width="72" Height="72" Style="{StaticResource RoundPlay}" 
                DataContext="{Binding ElementName=this, Path=DataContext}"
                cmd:ButtonBaseExtensions.Command="{Binding PlayStopCommand}"
                />

当用户单击按钮时，项目 ViewModel 中的 PlayStopCommand 被执行。我希望每当声音播放时按钮的样式设置为“RoundStop”。

如何将按钮的样式绑定到 ViewModel 中的属性（我应该使用什么属性类型），以便可以通过代码控制按钮的外观？

我定义了 RoundStop 样式，我只需要一种将其应用到代码中的按钮的方法。

原文

I have a play button in a AudioRecord View.

Currently it is declered as:

<Button Width="72" Height="72" Style="{StaticResource RoundPlay}" 
                DataContext="{Binding ElementName=this, Path=DataContext}"
                cmd:ButtonBaseExtensions.Command="{Binding PlayStopCommand}"
                />

When a user clicks the button, a PlayStopCommand in items ViewModel gets executed. I want the button to get its' style set to "RoundStop" whenever the sound is playing.

How can I bind the buttons' Style to a property in my ViewModel (what property type should I use), so that the look of the button is controllable from code?

I have RoundStop style defined, I just need a way to apply it to a button from code.

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喜你已久 2024-12-07 13:43:22

您应该在视图模型中定义播放状态（播放/停止），并使用转换器将 Button.Style 绑定到该属性。在转换器中，根据当前状态返回不同的样式（取自 App.Current.Resources）。

编辑：

以下是转换器的示例，应如下所示：

public class StateStyleConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return (PlaybackState)value == PlaybackState.Playing ? App.Current.Resources["RoundPlay"] : App.Current.Resources["RoundStop"];
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

在此示例中，PlaybackState 是一个枚举：

public enum PlaybackState
{
    Playing,
    Stopped
}

然后您应该将状态属性添加到视图模型中（通知更改的部分取决于用于 MVVM 的框架）：

private PlaybackState state;
public PlaybackState State
{
    get { return state; }
    set
    {
        state = value;
        RaiseNotifyPropertyChanged("State");
    }
}

在 XAML 中声明您的转换器：

<UserControl.Resources>
    <converters:StateStyleConverter x:Key="StateStyleConverter"/>
</UserControl.Resources>

最后将其绑定到按钮：

<Button Width="72" Height="72" Style="{Binding State, Converter={StaticResource StateStyleConverter}}" 
            DataContext="{Binding ElementName=this, Path=DataContext}"
            cmd:ButtonBaseExtensions.Command="{Binding PlayStopCommand}"
            />

You should define the playing state in you viewmodel (Playing/Stopped), and bind Button.Style to that property using a converter. In your converter, return a different style (taken from App.Current.Resources) based on the current state.

Edit:

Here's an example of your converter should look like:

public class StateStyleConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return (PlaybackState)value == PlaybackState.Playing ? App.Current.Resources["RoundPlay"] : App.Current.Resources["RoundStop"];
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

In this example, PlaybackState is an enum:

public enum PlaybackState
{
    Playing,
    Stopped
}

Then you should add the state property to your view model (The part where you notify the change depends on the framework you are using for MVVM):

private PlaybackState state;
public PlaybackState State
{
    get { return state; }
    set
    {
        state = value;
        RaiseNotifyPropertyChanged("State");
    }
}

Declare your converter in XAML:

<UserControl.Resources>
    <converters:StateStyleConverter x:Key="StateStyleConverter"/>
</UserControl.Resources>

And finally bind it to the button:

<Button Width="72" Height="72" Style="{Binding State, Converter={StaticResource StateStyleConverter}}" 
            DataContext="{Binding ElementName=this, Path=DataContext}"
            cmd:ButtonBaseExtensions.Command="{Binding PlayStopCommand}"
            />

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