元素被禁用时按钮上的灰色图像(简单而美观)

Question

当按钮被禁用时,我希望灰显我的图像(在按钮上).当我在按钮上有文本(没有图像)时,文本显示为灰色(将图像作为按钮内容,它们不会变灰).有没有简单而美丽的方法呢？

这是我的xaml文件:

<Window x:Class="WpfApplication2.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <Grid.RowDefinitions>
                <RowDefinition Height="Auto" />
                <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <ToolBarTray VerticalAlignment="Top" Background="{DynamicResource {x:Static SystemColors.ControlBrushKey}}" IsLocked="true" Grid.Row="0">
            <ToolBar Background="{DynamicResource {x:Static SystemColors.ControlBrushKey}}" Band="1" BandIndex="1">
                <Button Command="{Binding Button1}" RenderOptions.BitmapScalingMode="NearestNeighbor">
                    <Button.Content>
                        <Image Source="open.ico"></Image>
                    </Button.Content>
                </Button>
                <Button Command="{Binding Button2}" RenderOptions.BitmapScalingMode="NearestNeighbor">
                    <Button.Content>
                        <Image Source="open.ico"></Image>
                    </Button.Content>
                </Button>
            </ToolBar>
        </ToolBarTray>
    </Grid>
</Window>

这是我的代码隐藏文件:

public partial class MainWindow : Window
{
    private RelayCommand _button1;
    private RelayCommand _button2;

    public MainWindow()
    {
        InitializeComponent();
        DataContext = this;
    }

    public ICommand Button1
    {
        get
        {
            if (_button1 == null)
            {
                _button1 = new RelayCommand(Button1E, Button1C);
            }
            return _button1;
        }
    }

    public ICommand Button2
    {
        get
        {
            if (_button2 == null)
            {
                _button2 = new RelayCommand(Button2E, Button2C);
            }
            return _button2;
        }
    }

    public void Button1E(object parameter)
    {
        Trace.WriteLine("Button 1");
    }

    public bool Button1C(object parameter)
    {
        return true;
    }

    public void Button2E(object parameter)
    {
        Trace.WriteLine("Button 2");
    }

    public bool Button2C(object parameter)
    {
        return false;
    }
}

Answer 1

正如Thomas Lebrun在他的文章中所说的如何灰化MenuItem的图标？目前最好的方法可能是创建一个小类AutoGreyableImage,它允许你在控制被停用时自动变成灰色的图像.

以下是如何使用它:

<MenuItem Header="Edit">
    <MenuItem x:Name="miPaste"
              Header="Paste">
        <MenuItem.Icon>
            <local:AutoGreyableImage Source="pack://application:,,,/Images/Paste.png"
                                                   />
        </MenuItem.Icon>
    </MenuItem>
</MenuItem>
 

以下是实施:

/// <summary>
/// Class used to have an image that is able to be gray when the control is not enabled.
/// Author: Thomas LEBRUN (http://blogs.developpeur.org/tom)
/// </summary>
public class AutoGreyableImage : Image
{
    /// <summary>
    /// Initializes a new instance of the <see cref="AutoGreyableImage"/> class.
    /// </summary>
    static AutoGreyableImage()
    {
        // Override the metadata of the IsEnabled property.
        IsEnabledProperty.OverrideMetadata(typeof(AutoGreyableImage), new FrameworkPropertyMetadata(true, new PropertyChangedCallback(OnAutoGreyScaleImageIsEnabledPropertyChanged)));
    }
    /// <summary>
    /// Called when [auto grey scale image is enabled property changed].
    /// </summary>
    /// <param name="source">The source.</param>
    /// <param name="args">The <see cref="System.Windows.DependencyPropertyChangedEventArgs"/> instance containing the event data.</param>
    private static void OnAutoGreyScaleImageIsEnabledPropertyChanged(DependencyObject source, DependencyPropertyChangedEventArgs args)
    {
        var autoGreyScaleImg = source as AutoGreyableImage;
        var isEnable = Convert.ToBoolean(args.NewValue);
        if (autoGreyScaleImg != null)
        {
            if (!isEnable)
            {
                // Get the source bitmap
                var bitmapImage = new BitmapImage(new Uri(autoGreyScaleImg.Source.ToString()));
                // Convert it to Gray
                autoGreyScaleImg.Source = new FormatConvertedBitmap(bitmapImage, PixelFormats.Gray32Float, null, 0);
                // Create Opacity Mask for greyscale image as FormatConvertedBitmap does not keep transparency info
                autoGreyScaleImg.OpacityMask = new ImageBrush(bitmapImage);
            }
            else
            {
                // Set the Source property to the original value.
                autoGreyScaleImg.Source = ((FormatConvertedBitmap) autoGreyScaleImg.Source).Source;
                // Reset the Opcity Mask
                autoGreyScaleImg.OpacityMask = null;
            }
        }
    }
}
 

结果如下:

来源

Answer 2

您可以使用像素着色器自动执行此操作。

Answer 3

或者通过附加属性相同。

<Image behaviors:GrayoutImageBehavior.GrayOutOnDisabled="True" Source="/WpfApp;component/Resources/picture.png" />

灰度图像行为：

public class GrayoutImageBehavior
{
    public static readonly DependencyProperty GrayOutOnDisabledProperty = DependencyProperty.RegisterAttached("GrayOutOnDisabled", typeof(bool), typeof(GrayoutImageBehavior), new PropertyMetadata(default(bool), OnGrayOutOnDisabledChanged));
    public static void SetGrayOutOnDisabled(Image element, bool value) { element.SetValue(GrayOutOnDisabledProperty, value); }
    public static bool GetGrayOutOnDisabled(Image element) { return (bool)element.GetValue(GrayOutOnDisabledProperty); }

    private static void OnGrayOutOnDisabledChanged(DependencyObject obj, DependencyPropertyChangedEventArgs args)
    {
        Image image = (Image) obj;
        image.IsEnabledChanged -= OnImageIsEnabledChanged;

        if ((bool)args.NewValue)
            image.IsEnabledChanged += OnImageIsEnabledChanged;

        ToggleGrayOut(image); // initial call
    }

    private static void OnImageIsEnabledChanged(object sender, DependencyPropertyChangedEventArgs args)
    {
        var image = (Image)sender;
        ToggleGrayOut(image);
    }

    private static void ToggleGrayOut(Image image)
    {
        try
        {
            if (image.IsEnabled)
            {
                var grayImage = image.Source as FormatConvertedBitmap;
                if (grayImage != null)
                {
                    image.Source = grayImage.Source; // Set the Source property to the original value.
                    image.OpacityMask = null; // Reset the Opacity Mask
                    image.Opacity = 1.0;
                }
            }
            else
            {
                var bitmapImage = default(BitmapImage);

                if (image.Source is BitmapImage)
                    bitmapImage = (BitmapImage) image.Source;
                else if (image.Source is BitmapSource) // assume uri source
                    bitmapImage = new BitmapImage(new Uri(image.Source.ToString()));

                if (bitmapImage != null)
                {
                    image.Source = new FormatConvertedBitmap(bitmapImage, PixelFormats.Gray32Float, null, 0); // Get the source bitmap
                    image.OpacityMask = new ImageBrush(bitmapImage); // Create Opacity Mask for grayscale image as FormatConvertedBitmap does not keep transparency info
                    image.Opacity = 0.3; // optional: lower opacity
                }
            }
        }
        catch (Exception ex)
        {
            LogicLogger.WriteLogEntry("Converting image to grayscale failed", LogLevel.Debug, false, ex);
        }
    }
}