WPF 触发器绑定到 MVVM 属性
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/1795476/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
WPF Trigger binding to MVVM property
提问by David Ward
I have a datatemplate containing an image that I want to be hidden if the the value of a property in a ViewModel is true. Can anyone tell me why the the xaml below does not work?
我有一个包含图像的数据模板，如果 ViewModel 中的属性值为 true，我希望将其隐藏。谁能告诉我为什么下面的 xaml 不起作用？
<Image x:Name="img" Source="..\Images\List_16.png" Margin="0,0,5,0">
<Image.Style>
<Style>
<Style.Triggers>
<DataTrigger Binding="{Binding CurrentListHasPendingChanges}" Value="True">
<Setter Property="Image.Visibility" Value="Hidden" />
</DataTrigger>
<DataTrigger Binding="{Binding CurrentListHasPendingChanges}" Value="False">
<Setter Property="Image.Visibility" Value="Visible" />
</DataTrigger>
</Style.Triggers>
</Style>
</Image.Style>
</Image>
采纳答案by Natrium
isn't that
那不是
<Setter Property="Visibility" Value="Hidden" />
?
?
I assume you use INotifyProptyChanged.
我假设您使用 INotifyProptyChanged。
EDITI did some Googling and I think you need to use some sort of template in order to make the trigger work.
编辑我做了一些谷歌搜索，我认为你需要使用某种模板才能使触发器工作。
eg.: http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/ae2dbfb7-5dd6-4352-bfa1-53634289329d
例如：http: //social.msdn.microsoft.com/Forums/en-US/wpf/thread/ae2dbfb7-5dd6-4352-bfa1-53634289329d
http://www.thejoyofcode.com/Help_Why_cant_I_use_DataTriggers_with_controls_in_WPF.aspx
http://www.thejoyofcode.com/Help_Why_cant_I_use_DataTriggers_with_controls_in_WPF.aspx
回答by Stanislav Kniazev
Try removing "Image" part from Property="Image.Visibility" so you'll have:
尝试从 Property="Image.Visibility" 中删除 "Image" 部分，这样你就会有：
<Setter Property="Visibility" Value="Hidden"/>
and add TargetType to your Style:
并将 TargetType 添加到您的样式：
<Style TargetType="{x:Type Image}">
回答by a_hardin
I just did something similar using a ContentControl.
我只是使用 ContentControl 做了类似的事情。
<ContentControl Content="{Binding CurrentListHasPendingChanges}">
<ContentControl.ContentTemplate>
<DataTemplate>
<Image x:Name="img" Source="..\Images\List_16.png" Margin="0,0,5,0" Visibility="Hidden" />
<DataTemplate.Triggers>
<DataTrigger Binding="{Binding}" Value="False">
<Setter Property="Image.Visibility" Value="Visible" />
</DataTrigger>
</DataTemplate.Triggers>
</DataTemplate>
</ContentControl.ContentTemplate>
</ContentControl>
回答by Adel
In my opinion we not need to use Triggers, with only the Binding it works well. To make binding to a property model, you can use BooleanToVisibilityConverter Is declared as follows:
在我看来，我们不需要使用 Triggers，只需要 Binding 就可以了。要绑定到属性模型，可以使用 BooleanToVisibilityConverter 声明如下：
<UserControl.Resources>
<BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter"/>
</UserControl.Resources>
And how to use it is simple, just point to the key stated above:
而且怎么使用也很简单，直接指向上面说的key即可：
<Image HorizontalAlignment="Left" Height="16" VerticalAlignment="Center" Width="16"
Visibility="{Binding HasError, Converter={StaticResource BooleanToVisibilityConverter}}"
Source="/myPath;component/Resources/Images/image1.png"/>
The property in the ViewModel:
ViewModel 中的属性：
private bool _hasError = false;
public bool HasError
{
get { return !string.IsNullOrEmpty(_messageError); }
set
{
_hasError = value;
this.NotifyOfPropertyChange(() => this.HasError);
}
}
