Question

我有一个Image控件绑定到viewmodel中的两个Bitmap属性（这些不是依赖属性）。根据切换按钮切换源。绑定到切换按钮的触发器工作并切换图像源但是当Bitmap属性中的任何一个更改时，图像不会更新。显示默认图像（最初设置），但在更改属性时不会更新。视图模型已实现INotifyPropertyChanged，并且当位图更改但未更新Image控件时会通知代码的其他部分。

仅在设置初始图像时才调用转换器，而不是在后续更新中调用。

<Image Grid.Row="1" 
                Stretch="Uniform" 
                HorizontalAlignment="Stretch" 
                VerticalAlignment="Stretch" 
                Width="Auto"
                Height="Auto">
                <Image.Style>
                    <Style TargetType="{x:Type Image}">
                        <Style.Triggers>
                            <DataTrigger Binding="{Binding ToggleImage}" Value="True">
                                <Setter Property="Source" Value="{Binding ProcessedImage, Converter={StaticResource ImageToSourceConverter},
                                     UpdateSourceTrigger=PropertyChanged, Mode=OneWay}" />
                            </DataTrigger>
                            <DataTrigger Binding="{Binding ToggleImage}" Value="False">
                                <Setter Property="Source" Value="{Binding OriginalImage, Converter={StaticResource ImageToSourceConverter},
                                     UpdateSourceTrigger=PropertyChanged, Mode=OneWay}" />
                            </DataTrigger>
                        </Style.Triggers>
                    </Style>
                </Image.Style>
            </Image>

这里是转换器代码

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Windows;
using System.Windows.Data;
using System.Windows.Interop;
using System.Windows.Media;
using System.Windows.Media.Imaging;

namespace OMR_Scanner_Application.Converters
{
    class ImageToSourceConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter,
                System.Globalization.CultureInfo culture)
        {
            Bitmap image = value as Bitmap;
            if (image != null)
            {
                MemoryStream ms = new MemoryStream();
                image.Save(ms, ImageFormat.Bmp);
                ms.Seek(0, SeekOrigin.Begin);
                BitmapImage bi = new BitmapImage();
                bi.CacheOption = BitmapCacheOption.None;
                bi.BeginInit();
                bi.StreamSource = ms;
                bi.EndInit();
                return bi;
            }
            return null;
        }

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

触发器中的WPF图像控件绑定不起作用

0 个答案: