19

DynamicResource使用扩展时有没有办法定义转换器？有点像 

<RowDefinition Height="{Binding Source={DynamicResource someHeight}, Converter={StaticResource gridLengthConverter}}" />

不幸的是，这给了我以下例外：

不能在“Binding”类型的“Source”属性上设置“DynamicResourceExtension”。只能在 DependencyObject 的 DependencyProperty 上设置“DynamicResourceExtension”。

4

4 回答 4

23

我知道我真的迟到了，但绝对有效的是像这样为 DynamicResource使用BindingProxy

<my:BindingProxy x:Key="someHeightProxy" Data="{DynamicResource someHeight}" />

然后将转换器应用于代理

<RowDefinition Height="{Binding Source={StaticResource someHeightProxy}, Path=Data, Converter={StaticResource gridLengthConverter}}" />
于 2014-06-15T06:59:01.457 回答
4

尝试这样的事情：

标记扩展：

public class DynamicResourceWithConverterExtension : DynamicResourceExtension
{
    public DynamicResourceWithConverterExtension()
    {
    }

    public DynamicResourceWithConverterExtension(object resourceKey)
            : base(resourceKey)
    {
    }

    public IValueConverter Converter { get; set; }
    public object ConverterParameter { get; set; }

    public override object ProvideValue(IServiceProvider provider)
    {
        object value = base.ProvideValue(provider);
        if (value != this && Converter != null)
        {
            Type targetType = null;
            var target = (IProvideValueTarget)provider.GetService(typeof(IProvideValueTarget));
            if (target != null)
            {
                DependencyProperty targetDp = target.TargetProperty as DependencyProperty;
                if (targetDp != null)
                {
                    targetType = targetDp.PropertyType;
                }
            }
            if (targetType != null)
                return Converter.Convert(value, targetType, ConverterParameter, CultureInfo.CurrentCulture);
        }

        return value;
    }
}

XAML：

<RowDefinition Height="{my:DynamicResourceWithConverter someHeight, Converter={StaticResource gridLengthConverter}}" />
于 2011-01-26T14:14:08.413 回答
3

@Thomas 的帖子非常接近，但正如其他人指出的那样，它仅在执行 MarkupExtension 时执行。

这是一个真正绑定的解决方案，不需要“代理”对象，并且像任何其他绑定一样编写，除了源和路径，你给它一个资源键......

如何创建支持转换器、StringFormat 的 DynamicResourceBinding？

于 2015-11-20T00:18:01.117 回答
1

我喜欢 mkoertgen 的回答。

这是一个适用于我的 VB.NET 中 IValueConverter 代理的改编示例。我的资源“VisibilityConverter”现在包含为 DynamicResource 并与 ConverterProxy“VisibilityConverterProxy”一起转发。

用法：

...
xmlns:binding="clr-namespace:Common.Utilities.ModelViewViewModelInfrastructure.Binding;assembly=Common"
...
<ResourceDictionary>
    <binding:ConverterProxy x:Key="VisibilityConverterProxy" Data="{DynamicResource VisibilityConverter}" />
</ResourceDictionary>
...
Visibility="{Binding IsReadOnly, Converter={StaticResource VisibilityConverterProxy}}"

代码：

Imports System.Globalization

Namespace Utilities.ModelViewViewModelInfrastructure.Binding

''' <summary>
''' The ConverterProxy can be used to replace StaticResources with DynamicResources.
''' The replacement helps to test the xaml classes. See ToolView.xaml for an example
''' how to use this class.
''' </summary>
Public Class ConverterProxy
    Inherits Freezable
    Implements IValueConverter

#Region "ATTRIBUTES"

    'Using a DependencyProperty as the backing store for Data.  This enables animation, styling, binding, etc...
    Public Shared ReadOnly DataProperty As DependencyProperty =
                                DependencyProperty.Register("Data", GetType(IValueConverter), GetType(ConverterProxy), New UIPropertyMetadata(Nothing))

    ''' <summary>
    ''' The IValueConverter the proxy redirects to
    ''' </summary>
    Public Property Data As IValueConverter
        Get
            Return CType(GetValue(DataProperty), IValueConverter)
        End Get
        Set(value As IValueConverter)
            SetValue(DataProperty, value)
        End Set
    End Property

#End Region


#Region "METHODS"

    Protected Overrides Function CreateInstanceCore() As Freezable
        Return New ConverterProxy()
    End Function

    Public Function Convert(ByVal value As Object, ByVal targetType As Type, ByVal parameter As Object, ByVal culture As CultureInfo) As Object Implements IValueConverter.Convert
        Return Data.Convert(value, targetType, parameter, culture)
    End Function

    Public Function ConvertBack(ByVal value As Object, ByVal targetType As Type, ByVal parameter As Object, ByVal culture As CultureInfo) As Object Implements IValueConverter.ConvertBack
        Return Data.ConvertBack(value, targetType, parameter, culture)
    End Function

#End Region



End Class

结束命名空间

于 2015-03-25T12:02:11.043 回答