Question

请帮助我解决此问题

错误：XLS0415：在以下位置找不到可附加属性“ TrueObject” 类型“ BooleanToObjectConverter”。 App1 RegstrationPage.xaml。

我尝试了这个Class property declaration in XAML，但是它不起作用。.DependencyObject无法b继承类。

    <?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:App1"
             xmlns:local1="clr-namespace:App1.Behavior"
             x:Class="App1.RegstrationPage" Padding="50,20">

    <ContentPage.Resources>
        <ResourceDictionary>
            <local:BooleanToObjectConverter x:Key="boolToStyleImage" x:TypeArguments="Style">

                <local:BooleanToObjectConverter.FalseObject>
                    <Style TargetType="Image">
                        <Setter Property="HeightRequest" Value="20" />
                        <Setter Property="Source" Value="{local1:ImageResource App1.Images.error.png}" />
                    </Style>
                </local:BooleanToObjectConverter.FalseObject>

                <local:BooleanToObjectConverter.TrueObject>
                    <Style TargetType="Image">
                        <Setter Property="HeightRequest" Value="20" />
                        <Setter Property="Source" Value="{local1:ImageResource App1.Images.success.png}" />
                    </Style>
                </local:BooleanToObjectConverter.TrueObject>
            </local:BooleanToObjectConverter>
            <local:BooleanToObjectConverter x:Key="boolToStyleEmail"
                                           x:TypeArguments="Style">
                <local:BooleanToObjectConverter.FalseObject>

                    <Style TargetType="Label" BasedOn="{StaticResource baseStyle}">
                        <Setter Property="TextColor" Value="#F44336" />
                        <Setter Property="Text" Value="Enter a valid email" />
                    </Style>
                </local:BooleanToObjectConverter.FalseObject>

                <local:BooleanToObjectConverter.TrueObject>
                    <Style TargetType="Label" BasedOn="{StaticResource baseStyle}">
                        <Setter Property="TextColor" Value="#4CAF50" />
                        <Setter Property="Text" Value="Your email looks good" />
                    </Style>
                </local:BooleanToObjectConverter.TrueObject>

            </local:BooleanToObjectConverter>

这是BooleanToObjectConverte类

public class BooleanToObjectConverter<T> :IValueConverter
{
    public static T FalseObject { get; set; }

    public static T TrueObject { get; set; }

    public object Convert(object value, Type targettype,
                          object parameter, CultureInfo culture)
    {
        return (bool)value ? TrueObject : FalseObject;
    }

    public object ConvertBack(object value, Type targettype,
                              object parameter, CultureInfo culture)
    {
        return ((T)value).Equals(TrueObject);
    }
}

Answer 1

不要将FalseObject和TrueObject设为静态；它们应该是公共实例属性。

Xmal类中的类属性减速

1 个答案: