将2个ViewModel绑定到一个XAML元素中 [英] Bind from 2 ViewModels in one XAML element

问题描述

我有兴趣尝试在一个元素中使用来自两个ViewModels的信息.这是我的样品.在页面的开头，我得到了这个

I am interested in trying to use information from two ViewModels in one element. Here is my sample. At the beginning of the page I got this

    <ContentPage.BindingContext>
        <vm: MainViewModel />
    </ContentPage.BindingContext> 

...在某一时刻，我有一个需要从2个虚拟机中获取值的元素.

... at one point I have an element that I need values from 2 VMs.

<TapGestureRecognizer Command="{Binding CommandValueFromAnotherViewModel}"
                      CommandParameter="{Binding StringValueFromCurrentViewModel}"> // This

    <TapGestureRecognizer.BindingContext>
             <vm:ViewModelBindingWithCommandValue />
    </TapGestureRecognizer.BindingContext>  

</TapGestureRecognizer> 

我对Command属性的绑定工作正常，但是有什么方法可以从包含"StringValueFromCurrentViewModel"属性的"MainViewModel"中设置CommandParameter值吗?

My binding for the Command property works perfectly, but is there any way to set my CommandParameter value from my "MainViewModel" that contains "StringValueFromCurrentViewModel" property ?

推荐答案

您可以尝试以下方法:

<ContentPage.BindingContext>
    <vm:MainViewModel x:Name="root"/>
</ContentPage.BindingContext> 

....


<TapGestureRecognizer Command="{Binding CommandValueFromAnotherViewModel}"
                  CommandParameter="{Binding StringValueFromCurrentViewModel,Source={x:Reference root}}">

<TapGestureRecognizer.BindingContext>
         <vm:ViewModelBindingWithCommandValue />
</TapGestureRecognizer.BindingContext>  

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