如何仅使用 XAML 显示不同的 Enum 图标? [英] How to display different Enum icons using XAML only?

问题描述

我想根据枚举值显示不同的图标/图像.例如，如果我有以下枚举:

I want to show a different icon/image depending on an enum value. For example, if I had the following enum:

  public enum UploadStatus
  {
      Unknown = 0,
      WaitingToUpload = 10,
      Uploading = 20,
      Uploaded = 30,
      UploadFailed = 40
  }

我想编写如下所示的 XAML:

I'd like to write XAML that looks something like this:

...

<EnumImage Value="{Binding Path=CurrentStatus}">
  <EnumImageItem Value="Unknown"         Image="/images/unknown.png" />
  <EnumImageItem Value="WaitingToUpload" Image="/images/clock.png" />
  <EnumImageItem Value="Uploading"       Image="/images/upload.png" />
  <EnumImageItem Value="Uploaded"        Image="/images/tick.png" />
  <EnumImageItem Value="UploadFailed"    Image="/images/error.png" />
</EnumImage>

...

我发现很多帖子都建议自定义 IValueConverters，但这些解决方案不符合 XAML 范式.

I've found many posts suggesting custom IValueConverters, but those solutions don't fit the XAML paradigm.

有任何指示或建议吗?

推荐答案

这里是一个值转换器，它维护XAML 范式"，即枚举值和图像之间的关系在 XAML 中维护.

Here is a Value converter which maintains the "XAML paradigm" that is the relationship between enum values and images is maintained in XAML.

[ContentProperty("Items")]
public class EnumToObjectConverter : IValueConverter
{
    public ResourceDictionary Items { get; set; }

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        string key = Enum.GetName(value.GetType(), value);
        return Items[key];
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException("This converter only works for one way binding");
    }
}

请注意，这是非常通用的，它实际上将任何枚举类型的值映射到任何任意对象.这是它在 Xaml 中的用法:-

Note that this is very generic it actually maps values of any enum type to any arbitary object. This is what its usage looks like in Xaml:-

<Grid.Resources>
  <local:EnumToObjectConverter x:Key="Icons">
    <ResourceDictionary>
 <BitmapImage x:Key="Unknown" UriSource="/images/unknown.png" />
      <BitmapImage x:Key="WaitingToUpload" UriSource="/images/clock.png" />        
      <BitmapImage x:Key="Uploading"       UriSource="/images/upload.png" />        
      <BitmapImage x:Key="Uploaded"        UriSource="/images/tick.png" />        
      <BitmapImage x:Key="UploadFailed"    UriSource="/images/error.png" />        
    </ResourceDictionary>
  </local:EnumToObjectConverter>
</Grid.Resources>

绑定枚举类型的属性时可以使用这个转换器:-

This converter can be used when binding property of the enum type:-

 <Image Source="{Binding Status, Converter={StaticResource Icons}}" />

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