如何从 XAML x:Array 中的 ViewModel 访问 const 字符串

Question

我正在使用一个转换器，我想为其传递 2 个转换器参数。我在 Converter 中有静态字符串，但我无法访问它。

问题陈述:

想要在 XAML x:Array 中访问 public static string STAR = "STAR";。

XAML:

<UserControl.Resources>
    <local:CustomGridLengthConverter x:Key="CustomGridLengthConverter"/>
</UserControl.Resources>

<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="*"/>
        <ColumnDefinition Width="Auto"/>
        <ColumnDefinition>
            <ColumnDefinition.Width>
                <Binding Path="CustomLength" Converter="{StaticResource CustomGridLengthConverter}">
                    <Binding.ConverterParameter>
                        <x:Array Type="{x:Type system:String}">
                            <system:String>AUTO</system:String>-->Working
                            <system:String>STAR</system:String>-->Working
                            <!--<local:CustomGridLengthConverter.STAR/>--> *NOT* Working
                        </x:Array>
                    </Binding.ConverterParameter>
                </Binding>
            </ColumnDefinition.Width>
        </ColumnDefinition>
  </Grid.ColumnDefinitions>

转换器代码：

public class CustomGridLengthConverter : IValueConverter
    {
        public static string ABSOLUTE = "ABSOLUTE";
        public static string AUTO= "AUTO";
        public static string STAR = "STAR";

        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
           double tempGridLengthVal = 0.0;

           //do necessary null/datatype check
           string[] params=parameter as string[];

           // use default value when 'value' is null
           string defaultValue=params[0];

           //use this value to specify if user wants absolute value or relative value.
           string convertTo=params[1];

           if (value.IsNotNull() && Double.TryParse(value.ToString(), out 
           tempGridLengthVal))
           {
            //If given value is parsable, create new GridLength with this value
            gridLength = new GridLength(tempGridLengthVal);

            //User can specify if they want to use the given value as exact 
             value or as a star percentage
            if (convertTo.Equals(STAR))
                gridLength = new GridLength(tempGridLengthVal,GridUnitType.Star);
            } 
        }

EDIT：这是与“another question”不同的用例，因为该问题值已分配给依赖对象，而我没有依赖对象对象，我只想将静态字符串值传递给数组。

谢谢，

RDV

Answer 1

您可以使用 x:Static 标记扩展：

<Binding.ConverterParameter>
    <x:Array Type="{x:Type system:String}">
        <system:String>AUTO</system:String>
        <system:String>STAR</system:String>
        <x:Static Member="local:CustomGridLengthConverter.STAR" />
    </x:Array>
</Binding.ConverterParameter>

如何从 XAML x:Array 中的 ViewModel 访问 const 字符串

How to access const string from ViewModel in XAML x:Array

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