禁用时变灰色的按钮图片

引言

我使用 WPF 已经几周了，用 XAML 模仿 Windows 控件确实令人沮丧。 我正在应用程序中构建一个菜单，发现当我的 Button 未启用时，Button 内部的图像不会自动转换为灰度。 这与典型的 Windows Forms 开发者所期望的不符。 所以这就是我的发现。

Using the Code

<Window x:Class="KLCardinal.Window1" x:Name="thisForm"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:KLCardinal"
    Title="Window1" Height="300" Width="300">
    <Window.Resources>
        <local:GrayScaleConverter x:Key="grayConv" />
    </Window.Resources>
    <Grid>
        <Button Template="{DynamicResource buttonTemplate}" 
            IsEnabled="False" Margin="63,111,34,111">
            <Button.Resources>
                <ControlTemplate x:Key="buttonTemplate" TargetType="{x:Type Button}">
                    <StackPanel x:Name="stPanel" HorizontalAlignment="Left" 
                    Width="Auto" Height="Auto" 
                                Orientation="Horizontal">
                        <Image x:Name="img" Width="30" Height="30" Stretch="Fill"/>
                        <TextBlock FontSize="14" Margin="5,0,0,0" 
                    VerticalAlignment="Center" Text="My Button" 
                    TextWrapping="Wrap"/>
                     </StackPanel>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsEnabled" Value="False">
                            <Trigger.Setters>
                                <Setter TargetName="img" Property="Source" 
                                    Value="{Binding ElementName=thisForm, 
                                    Path=MyButtonImage, 
                                    Converter={StaticResource grayConv}}" />
                                <Setter TargetName="stPanel" Property="BitmapEffect">
                                    <Setter.Value>
                                        <BlurBitmapEffect Radius="1" />
                                    </Setter.Value>
                                </Setter>
                            </Trigger.Setters>
                        </Trigger>
                        <Trigger Property="IsEnabled" Value="True">
                            <Trigger.Setters>
                                <Setter TargetName="img" Property="Source" 
                                    Value="{Binding ElementName=thisForm, 
                                    Path=MyButtonImage}" />
                                <Setter TargetName="stPanel" Property="BitmapEffect" 
                                    Value="{x:Null}" />
                            </Trigger.Setters>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Button.Resources>
        </Button>
    </Grid>
</Window> 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
namespace KLCardinal
{
    /// <summary>
    /// Interaction logic for Window1.xaml
    /// </summary>
    public partial class Window1 : Window
    {
        public static readonly DependencyProperty MyButtonImageProperty =
            DependencyProperty.Register("MyButtonImage", typeof(ImageSource), 
                typeof(Window1), new UIPropertyMetadata(null));
        public ImageSource MyButtonImage
        {
            get { return (ImageSource)GetValue(MyButtonImageProperty); }
            set { SetValue(MyButtonImageProperty, value); }
        }
        public Window1()
        {
            try
            {
                MyButtonImage = new ImageSourceConverter().ConvertFrom
                    (@"C:\Users\Public\Pictures\Sample Pictures\creek.jpg") 
                    as BitmapSource;
            }
            catch { }
            InitializeComponent();
        }
    }
}

现在，我们想要创建一个 Converter，它将一个像素格式为 Brga32 (PNG) 或 Brg32 (JPG) 的 BitmapSource 转换为灰度的 Brga32/Brg32 BitmapSource。

public class GrayScaleConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, 
            object parameter, System.Globalization.CultureInfo culture)
        {
            if(value is BitmapSource)
            {
                BitmapSource orgBmp = (BitmapSource)value;
                if (orgBmp.Format == PixelFormats.Bgra32)
                {
                    byte[] orgPixels = new byte[orgBmp.PixelHeight * 
                        orgBmp.PixelWidth * 4];
                    byte[] newPixels = new byte[orgPixels.Length];
                    orgBmp.CopyPixels(orgPixels, orgBmp.PixelWidth * 4, 0);
                    for (int i = 3; i < orgPixels.Length; i += 4)
                    {
                        int grayVal = ((int)orgPixels[i - 3] + 
                        (int)orgPixels[i - 2] + (int)orgPixels[i - 1]);
                        
                        if (grayVal != 0)
                            grayVal = grayVal / 3;
                        newPixels[i] = orgPixels[i]; //Set AlphaChannel
                        newPixels[i - 3] = (byte)grayVal;
                        newPixels[i - 2] = (byte)grayVal;
                        newPixels[i - 1] = (byte)grayVal;
                    }
                    return BitmapSource.Create(orgBmp.PixelWidth, orgBmp.PixelHeight, 
                        96, 96, PixelFormats.Bgra32, null, newPixels, 
                        orgBmp.PixelWidth * 4);
                }
            }
            return value;
        }
        public object ConvertBack(object value, Type targetType, object parameter, 
            System.Globalization.CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }     

历史

• 2007年12月18日：初始发布