wpf 在样式中指定列表框 ItemContainer 上的数据上下文类型
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Specify datacontext type on listbox ItemContainer in style
提问by Isantipov
In a ListBoxI have a ItemContainer's IsSelectedproperty bound to my ViewModel's IsSelectedproperty using <ListBox.ItemContainerStyle>syntax.
在ListBox我有一个 ItemContainerIsSelected的IsSelected属性使用<ListBox.ItemContainerStyle>语法绑定到我的 ViewModel 的属性。
It works fine, but I get a Resharper warning:
它工作正常，但我收到 Resharper 警告：
Cannot resolve property 'IsSelected' in data context of type "FooSolution.BarViewModel".
无法在“FooSolution.BarViewModel”类型的数据上下文中解析属性“IsSelected”。
How do I specify specify DataContext type on ListBox ItemContainer to get rid of this warning?
如何在 ListBox ItemContainer 上指定指定 DataContext 类型以消除此警告？
Here is the code. I have a BarViewModelclass:
这是代码。我有一BarViewModel堂课：
public ObservableCollection<FooViewModel> FooItems { get;set; }
BarViewModelis assigned to DataContext in the Control which contains the ListBox
BarViewModel分配给包含 ListBox 的 Control 中的 DataContext
and FooViewModelas follows:
并且FooViewModel，如下所示：
public bool IsSelected
{
get
{
return isSelected;
}
set
{
if (isSelected == value)
{
return;
}
isSelected = value;
RaisePropertyChanged(() => IsSelected);
}
}
and XAML like this:
和 XAML 像这样：
<ListBox ItemsSource="{Binding FooItems}" SelectionMode="Multiple">
<ListBox.ItemContainerStyle>
<Style TargetType="{x:Type ListBoxItem}">
<Setter Property="IsSelected" Value="{Binding IsSelected}" />
</Style>
</ListBox.ItemContainerStyle>
</ListBox>
UpdateI've tried setting d:DataContextusing a setter, as suggested by HighCore, but unfortunatelly, it doesn't help and even breaks the build:
更新我已经d:DataContext按照 HighCore 的建议尝试使用 setter 进行设置，但不幸的是，它没有帮助，甚至破坏了构建：
<Setter Property="d:DataContext" Value="{d:DesignInstance yourxmlns:yourItemViewModelClass}"/>
(Throws: Error 1 The tag 'DesignInstance' does not exist in XML namespace 'schemas.microsoft.com/expression/blend/2008';. Line 31 Position 50. )
（抛出：错误 1 XML 命名空间“schemas.microsoft.com/expression/blend/2008”中不存在标记“DesignInstance”；第 31 行第 50 行。）
Update 2Finaly, the solution is to set d:DataContexton the style element itself (see my answer bellow):
更新 2最后，解决方案是设置d:DataContext样式元素本身（见下面我的回答）：
<ListBox.ItemContainerStyle>
<Style TargetType="{x:Type ListBoxItem}" d:DataContext="{d:DesignInstance local:FooViewModel }">
<Setter Property="IsSelected" Value="{Binding IsSelected}" />
</Style>
回答by Isantipov
As pointed out by @HighCore the solution is to specify d:DataContextattribute from blend SDK, however, it worked only when set on a Style element itsself, not in the property setter:
正如@HighCore 所指出的，解决方案是d:DataContext从 blend SDK 中指定属性，但是，它仅在 Style 元素本身上设置时才起作用，而不是在属性设置器中：
<ListBox.ItemContainerStyle>
<Style TargetType="{x:Type ListBoxItem}" d:DataContext="{d:DesignInstance local:FooViewModel }">
<Setter Property="IsSelected" Value="{Binding IsSelected}" />
</Style>
</ListBox.ItemContainerStyle>
This removes Resharper's warning and also changes binding Path when property is renaimed on the ViewModel. Cool!
这消除了 Resharper 的警告，并且在 ViewModel 上重命名属性时也会更改绑定路径。凉爽的！
回答by N. Kudryavtsev
Specifying d:DataContext="{d:DesignInstance nmspc:Clz}"with other attributes of Styletag didn'thelp me: R# / IntelliSense really stopped highlighting properties I was binding to but the designer also showed me an error message instead of the view.
指定标签的d:DataContext="{d:DesignInstance nmspc:Clz}"其他属性对我没有帮助：R#/IntelliSense 确实停止了突出显示我绑定到的属性，但设计器还向我显示了错误消息而不是 view。Style
The trick I found out is to specify <d:Style.DataContext>insidethe Styletag. And it appeared to be so universal that it answers another question, about using interfaces as d:DataContext.
我发现的技巧是在标签<d:Style.DataContext>内指定Style。它似乎非常通用，以至于它回答了另一个问题，关于将接口用作d:DataContext.
Here is my answer to that question with a small example: https://stackoverflow.com/a/46637478/5598194
这是我用一个小例子回答这个问题：https: //stackoverflow.com/a/46637478/5598194
回答by Federico Berasategui
use d:DataContextlike this:
d:DataContext像这样使用：
<Setter Property="d:DataContext" Value="{d:DesignInstance yourxmlns:yourItemViewModelClass}"/>
You also need the following xmlnses added to the root element:
您还需要将以下xmlnses 添加到根元素：
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
回答by eexaxa
Addition to previous answers: to get rid of error
除了以前的答案：摆脱错误
Property 'DataContext' is not attachable to elements of type 'Style'
属性“DataContext”不可附加到“Style”类型的元素
add some dummy namespace
添加一些虚拟命名空间
xmlns:ignore="designTimeAttribute"
and use it now instead of d:DataContext
并立即使用它而不是 d:DataContext
<Style TargetType="{x:Type ListBoxItem}" ignore:DataContext="{d:DesignInstance local:FooViewModel }">
...
</Style>
