设置和图像CreatOptions和CacheOption在XAML

Question

我想设置我的CreateOptions和CacheOption像这样：

img = new BitmapImage(); 
img.BeginInit(); 
img.CacheOption = BitmapCacheOption.OnDemand; 
img.CreateOptions = BitmapCreateOptions.IgnoreImageCache; 
img.UriSource = new Uri("C:\\Temp\\MyImage.png", UriKind.Absolute); 
img.EndInit(); 

有没有办法在XAML装饰品做到这一点？或者我必须诉诸代码？

Answer 1

你可以把一个IValueConverter内：

[ValueConversion(typeof(string), typeof(ImageSource))] 
public class FilePathToImageConverter : IValueConverter 
{ 
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture) 
    { 
     if (value.GetType() != typeof(string) || targetType != typeof(ImageSource)) return false; 
     string filePath = value as string; 
     if (string.IsNullOrEmpty(filePath) || !File.Exists(filePath)) return DependencyProperty.UnsetValue; 
     BitmapImage image = new BitmapImage(); 
     try 
     { 
      using (FileStream stream = File.OpenRead(filePath)) 
      { 
       image.BeginInit(); 
       image.StreamSource = stream; 
       image.CacheOption = BitmapCacheOption.OnDemand; 
       image.CreateOptions = BitmapCacheOption.IgnoreImageCache; 
       image.EndInit(); 
      } 
     } 
     catch { return DependencyProperty.UnsetValue; } 
     return image; 
    } 

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) 
    { 
     return DependencyProperty.UnsetValue; 
    } 
} 

然后，您可以使用它在XAML这样的：

<Image Source="{Binding SomeFilePath, Converter={StaticResource 
    FilePathToImageConverter}, Mode=OneWay}" /> 

在代码中的某处：

SomeFilePath = "C:\\Temp\\MyImage.png";