C# 如何在 XAML 中使用枚举类型？
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How can I use enum types in XAML?
提问by davymartu
I'm learning WPF and I encountered the following problem:
我正在学习WPF，遇到了以下问题：
I have an enum type in another namespace than my XAML:
我在另一个命名空间中有一个枚举类型而不是我的 XAML：
public enum NodeType
{
Type_SYSTEM = 1, // System
Type_DB = 2, // Database
Type_ROOT = 512, // Root folder
Type_FOLDER = 1024, // Folder
}
in my XAML I'd like to trigger an image with an integer
在我的 XAML 中，我想用整数触发图像
<Image.Style>
<Style TargetType="{x:Type Image}">
<Style.Triggers>
<DataTrigger Binding="{Binding Type}" Value="{NodeType: }">
<Setter Property="Source" Value="/Images/DB.PNG"/>
</DataTrigger>
<DataTrigger Binding="{Binding Type}" Value="128">
<Setter Property="Source" Value="/Images/SERVER.PNG"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Image.Style>
Is there a way to get an integer value and compare it with an enum type directly in XAML code?
有没有办法直接在 XAML 代码中获取整数值并将其与枚举类型进行比较？
My enum is in namespace AnotherNamespace.Types
我的枚举在命名空间中 AnotherNamespace.Types
<DataTrigger Binding="{Binding IntegerType}" Value="MyEnumType.Type_DB">
<Setter Property="Source" Value="/Images/SERVER.PNG"/>
采纳答案by Rachel
I had a similar question here, and my end result was to create a generic IValueConverterthat passed the enumvalue I wanted to match in as the ConverterParameter, and it returns trueor falsedepending on if the bound value matches the (int)value of the Enum.
我在这里有一个类似的问题，我的最终结果是创建一个通用的IValueConverter，它传递enum我想要匹配的值作为ConverterParameter，它返回true或false取决于绑定值是否与(int)枚举的值匹配。
The end result looks like this:
最终结果如下所示：
XAML Code:
XAML 代码：
<DataTrigger Value="True"
Binding="{Binding SomeIntValue,
Converter={StaticResource IsIntEqualEnumConverter},
ConverterParameter={x:Static local:NodeType.Type_DB}}">
Converter
转换器
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
if (parameter == null || value == null) return false;
if (parameter.GetType().IsEnum && value is int)
{
return (int)parameter == (int)value;
}
return false;
}
回答by tpartee
You just need to make sure that your namespace is accounted-for in your XAML header then you can reference both custom DPs and enum values directly in your markup.
您只需要确保您的命名空间在您的 XAML 标头中得到考虑，然后您就可以直接在您的标记中引用自定义 DP 和枚举值。
For example I use this code to do just that:
例如，我使用此代码来做到这一点：
<DataTemplate.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ListBoxItem}}}" Value="True" />
<Condition Binding="{Binding Type}" Value="{x:Static loc:AppProfileItemType.Custom}" />
</MultiDataTrigger.Conditions>
<MultiDataTrigger.Setters>
<Setter TargetName="PART_Delete" Property="Visibility" Value="{x:Static Visibility.Visible}" />
</MultiDataTrigger.Setters>
</MultiDataTrigger>
</DataTemplate.Triggers>
Note that you can't access DataTriggers in a Style, you need to instead make a DataTemplate or ControlTemplate for that (however, .NET 4 adds the ability to set triggers in styles). You can override the ControlTemplate from a Style like so:
请注意，您不能在样式中访问 DataTriggers，您需要为此创建一个 DataTemplate 或 ControlTemplate（但是，.NET 4 添加了在样式中设置触发器的能力）。您可以像这样从样式覆盖 ControlTemplate：
<Style x:Key="MyCustomButtonStyle" TargetType="Button">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<ContentPresenter />
<ControlTemplate.Triggers>
<!-- Put your DataTriggers here -->
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
For DataTemplates you want to have bindings to an object, you can simply use a ContentPresenter and set its content to the object you want to display along with a DataTemplate definition to use for display of the object. There's always a way to use DataTriggers it's just not always direct or as simple as using a Style.
对于希望绑定到对象的 DataTemplate，您可以简单地使用 ContentPresenter 并将其内容设置为要显示的对象以及用于显示对象的 DataTemplate 定义。总有一种方法可以使用 DataTriggers，但并不总是直接或像使用 Style 那样简单。
