Question

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：

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

我想编写看起来像这样的XAML：

...

<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>

...

我发现有很多帖子建议自定义 IValueConverters ，但这些解决方案不符合XAML范例。

有任何指示或建议吗？

Answer 1

这是一个值转换器，它维护“XAML范例”，即在XAML中维护枚举值和图像之间的关系。

[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仲裁对象。这就是它在Xaml中的用法： -

<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>

当枚举类型的绑定属性时，可以使用此转换器： -

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

Answer 2

您的EnumImage可以使用Image与DataTrigger：

进行设置

   <Image Tag="{Binding Gender}" Width="48" Height="48">
      <Image.Style>
        <Style TargetType="Image">
            <Style.Triggers>
                <DataTrigger  Binding="{Binding Path=Tag, RelativeSource={RelativeSource Self}}" Value="Male">
                    <Setter Property="Source" Value="/Resources/Client_Male.png"/>
                </DataTrigger >
                <DataTrigger  Binding="{Binding Path=Tag, RelativeSource={RelativeSource Self}}" Value="Female">
                    <Setter Property="Source" Value="/Resources/Client_Female.png"/>
                </DataTrigger >
            </Style.Triggers>
        </Style>
      </Image.Style>
     </Image>

来源：Displaying an image based on value in XAML

如何仅使用XAML显示不同的枚举图标？

2 个答案: