使用ViewModel中的多态性绑定到XAML中带有参数的方法 [英] Binding to a method with parameter in XAML using polymorphism in ViewModel

问题描述

我的ResultView中有一个带有六个选项卡的TabControl.位于该视图后面的ViewModel可以是ResultTypeOneViewModel或ResultTypeTwoViewModel，它们每个都派生自ResultViewModel，但是您可以将结果查看器与任何一种结果类型互换使用.

I have a TabControl with six tabs in my ResultView. The ViewModel that sits behind this View can be either a ResultTypeOneViewModel or ResultTypeTwoViewModel, each of which derives from ResultViewModel but you can interchangeably use the result viewer with either result type.

区别在于，在ResultTypeOneViewModel中，标签1& 3需要可见，其余隐藏. 在ResultTypeTwoViewModel中，选项卡2、3、4、5、6必须是可见的，而选项卡1是隐藏的.

The difference is that in ResultTypeOneViewModel, tabs 1 & 3 need to be visible and the rest hidden. In ResultTypeTwoViewModel, tabs 2, 3, 4, 5, 6 need to be visible and tab 1 hidden.

我想通过

<TabItem Name="1" Visibility={Binding IsTabVisible(0)}>
<TabItem Name="2" Visibility={Binding IsTabVisible(1)}>
<TabItem Name="3" Visibility={Binding IsTabVisible(2)}>
etc...

在ResultsViewModel中有一个抽象方法声明，例如

And have an abstract method declaration in ResultsViewModel such as

public abstract Visibility IsTabVisible(int index);

在ResultsOneViewModel中有

And in ResultsOneViewModel have

public override Visibility IsTabVisible(int index)
{
    if (index == 0 || index == 2) return Visibility.Visible;
    return Visibility.Hidden;
}

在ResultsTwoViewModel中有

And in ResultsTwoViewModel have

public override Visibility IsTabVisible(int index)
{
    if (index == 0) return Visibility.Hidden;
    return Visibility.Visible;
}

但是我无法弄清楚如何通过iN WPF XAML绑定通过参数调用类似的方法.

But I cannot figure out how to call a method like this with a parameter through bindings iN WPF XAML.

任何人都可以建议我该怎么做，或者如果无法通过这种方法来解决我的另一种方法呢?

Can anyone suggest how I can do this or if it's not possible via this method, another way I could solve this problem?

推荐答案

要直接回答您的问题，您可以使用ObjectDataProvider来为您调用方法，以便处理结果:

To answer your question directly, you can use the ObjectDataProvider to call a method for you so you can work with the results:

xmlns:System="clr-namespace:System;assembly=mscorlib"
xmlns:Windows="clr-namespace:System.Windows;assembly=PresentationCore"

...

<Window.Resources>
    <ObjectDataProvider x:Key="IsTab1VisibleMethod" 
        ObjectType="{x:Type Windows:Visibility}" IsAsynchronous="True" 
        MethodName="IsTabVisible">
        <ObjectDataProvider.MethodParameters>
            <System:Int32>0</System:Int32>
        </ObjectDataProvider.MethodParameters>
    </ObjectDataProvider>
</Window.Resources>

然后，您应该能够像这样访问结果(但每个TabItem都需要其中之一):

You should then be able to access the result like this (but you'd need one of these for each TabItem):

<TabItem Visibility="{Binding Source={StaticResource IsTab1VisibleMethod}}" />

但是，通常不是在代码中操作UI属性(如Visibility)的好习惯，因此更好的主意是使用BooleanToVisibilityConverter到Bind的Visibility属性到bool的值，例如@ Highcore建议.您可以在将按钮可见性绑定到ViewModel中的bool值在此处发布在StackOverflow上.

However, it's generally not good practice to manipulate UI properties such as Visibility in code, so a better idea would be to use a BooleanToVisibilityConverter to Bind the Visibility properties to bool values as @Highcore suggested. You can see an example of this in the Binding a Button Visibility to bool value in ViewModel post here on StackOverflow.

我认为，更好的解决方案是为每个视图模型简单地提供一个视图.

In my opinion, an even better solution would be to simply provide one view for every view model.

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