[英]Windows 10 x:Bind to SelectedItem
I'm trying to port/adopt my Windows RT app to WIndows10 and I'm trying out the new bindings x:Bind. 我正在尝试移植/采用我的Windows RT应用程序到WIndows10,我正在尝试新的绑定x:Bind。
So far I'm able to bind to my ViewModel properties and other Viewelements. 到目前为止,我能够绑定到我的ViewModel属性和其他Viewelements。 But now I'm trying to bind the text of a TextBox to a SelectedItem of a GridView.
但现在我正在尝试将TextBox的文本绑定到GridView的SelectedItem。
In classic binding I'm doing it like that. 在经典绑定中,我就是这样做的。
<TextBox x:Name="tb_textgroup"
Grid.Row="1"
PlaceholderText="Change Groupname"
Text="{Binding UpdateSourceTrigger=PropertyChanged,
ElementName=gv_textgroup,
Mode=TwoWay,Path=SelectedItem.bezeich}"
IsEnabled="{Binding UpdateSourceTrigger=PropertyChanged,
ElementName=gv_textgroup,
Mode=TwoWay,Path=SelectedItem.edit_activated}"
Margin="20,10,20,0"
/>
I was trying it with 我正在尝试
But None of it worked... any ideas? 但它没有奏效......任何想法?
And can someone explain me what to do with "DependencyProperty". 并且有人可以解释我如何处理“DependencyProperty”。 I watched the viedo from "build 2015" and have the sample codes.
我从“build 2015”中看到了viedo,并提供了示例代码。 But it's saying nothing to me... I'm quite a newbie...
但它对我说什么......我是一个新手......
Many thanks for your help 非常感谢您的帮助
I'm not sure why this works, but if you create an object-to-object converter, x:Bind
works for two-way conversion on any SelectedItem
. 我不确定为什么会这样,但是如果你创建一个对象到对象的转换器,
x:Bind
可以在任何SelectedItem
上进行双向转换。
public class NoopConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, string language)
{
return value;
}
public object ConvertBack(object value, Type targetType, object parameter, string language)
{
return value;
}
}
And you can use it like this: 你可以像这样使用它:
<ListView ItemsSource="{x:Bind ViewModel.Items}"
SelectedItem="{x:Bind ViewModel.SelectedItem, Mode=TwoWay, Converter={StaticResource NoopConverter}}"
...
Special thanks to runceel for his public samples. 特别感谢runceel的公开样本。
You cannot use x:Bind on the SelectedItem of a GridView. 您不能在GridView的SelectedItem上使用x:Bind。 This is because the SelectedItem is an object, so it can be anything.
这是因为SelectedItem是一个对象,所以它可以是任何东西。 x:Bind needs to have actual classes/interfaces.
x:绑定需要有实际的类/接口。 x:Bind does not use reflection to find properties like Binding does.
x:Bind不使用反射来查找像Binding这样的属性。
You can accomplish this by x:Bind the SelectedItem of the GridView to your view model and then x:Bind to that from the TextBlock. 您可以通过x完成此操作:将GridView的SelectedItem绑定到视图模型,然后将x:绑定到TextBlock中的那个。 I'm not sure this would really help performance as much as you would like.
我不确定这对你的表现有多大帮助。
public class ViewModel
{
public MyItem SelectedItem { get; set; } //fire prop changed
}
<GridView SelectedItem="{x:Bind SelectedItem, mode=Twoway}"/>
<TextBlock Text="{x:Bind ViewModel.SelectedItem.bezeich}"
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