Xamarin样式静态资源绑定 [英] Xamarin Style staticresource binding

问题描述

是否可以在Xamarin Forms中将静态资源进行数据绑定? 像

would it be possible to databind a static resource in Xamarin Forms? Something like

Style="{StaticResource {Binding foo, StringFormat='SomeStyle{0}'}}"

谢谢

推荐答案

您可能想要的是一个Value Converter，它可以为您处理StaticResource的位置.完整的Microsoft文档此处

What you probably want is a Value Converter that handles locating the StaticResource for you. Full Microsoft Documentation here.

在XAML元素上，您将执行以下操作:

On your XAML element, you'd do something like this:

<Entry Style="{Binding foo, Converter={StaticResource FooToStyleConverter}}"/>

您的转换器将像这样工作:

Your converter would work something like this:

public class FooToStyleConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        var someValue = (string)value; // Convert 'object' to whatever type you are expecting

        // evaluate the converted value
        if (someValue != null && someValue == "bar")
            return (Style)App.Current.Resources["StyleOne"]; // return the desired style

        return (Style)App.Current.Resources["StyleTwo"];
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        // Usually unused, but inverse the above logic if needed
        throw new NotImplementedException();
    }
}

最后，将您的转换器设置为App.xaml中的静态资源(或页面上的本地资源)，以便您的页面可以正确地引用它.

Lastly, set up your converter as a Static Resource in App.xaml (or as a local resource on the page) so your page can properly reference it

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:DataBindingDemos">
    <ContentPage.Resources>
         <ResourceDictionary>
              <local:FooToStyleConverter x:Key="FooToStyleConverter" />
              ....

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