WPF 在从手机 8 上的 xaml 文本和 XamlReader 创建的数据模板中使用转换器 [英] WPF using converter in datatemplate created from xaml text and XamlReader on phone 8

问题描述

我正在使用这样的文本 xaml 生成 DataTemplate:

I'm generating a DataTemplate using a text xaml like this:

var dataTemplate = (DataTemplate)XamlReader.Load(xaml.ToString());

其中一个元素是一个 CheckBox，它的转换器指向一个 StaticResource:

One of the elements is a CheckBox bound with it's converter pointing to a StaticResource:

    StringBuilder xaml = new StringBuilder();
    xaml.AppendFormat(@"          <CheckBox");
    xaml.AppendFormat(@" IsChecked=""{{Binding [{0}], Converter={{StaticResource stringValueToBoolConverter}}, Mode=TwoWay}}""", header.ID);
    xaml.AppendFormat(@" />");

文本中存在此转换器引用会导致在电话上的 Application_UnhandledException 中捕获异常.消息如下所示:

The presence of this converter reference in the text causes an exception caught in the Application_UnhandledException on phone. The message looks like this:

-       InnerException  {System.Exception: Error HRESULT E_FAIL has been returned from a call to a COM component.
   at MS.Internal.XcpImports.CheckHResult(UInt32 hr)
   at MS.Internal.XcpImports.UIElement_Measure_WithDesiredSize(UIElement element, Size availableSize)
   at System.Windows.UIElement.Measure_WithDesiredSize(Size availableSize)
   at System.Windows.Controls.VirtualizingStackPanel.MeasureChild(UIElement child, Size layoutSlotSize)
   at System.Windows.Controls.VirtualizingStackPanel.MeasureOverride(Size constraint)
   at System.Windows.FrameworkElement.MeasureOverride(IntPtr nativeTarget, Double inWidth, Double inHeight, Double& outWidth, Double& outHeight)}   System.Exception

模板用于在列表框中创建一行，并且控件在其资源中声明了转换器:

The template is used to create a row in a listbox and the control has the converter declared in it's resources:

<UserControl.Resources>
        <converters:StringValueToBoolConverter x:Key="stringValueToBoolConverter" />
</UserControl.Resources>

我想在某个创建步骤中，xaml->objects 的对象创建过程找不到转换器 - 有没有办法绕过它?

I suppose that at some creation step, the object creation process of xaml->objects can't find the converter - is there a way to get around it?

**添加

我也刚刚测试了为复选框添加加载 - 与添加转换器相同的断言

I also just tested adding a Loaded for the check box - same assert as adding the converter

StringBuilder xaml = new StringBuilder();
xaml.AppendFormat(@"          <CheckBox");
xaml.AppendFormat(@" IsChecked=""{{Binding [{0}],  Mode=TwoWay}}""", header.ID);
xaml.AppendFormat(@" Loaded=""FrameworkElement_OnLoaded""");

也许有一种方法可以向加载器提供此上下文?

Maybe there's a way to provide this context to the loader?

推荐答案

模板用于在列表框中创建一行，并且控件在其资源中声明了转换器:

The template is used to create a row in a listbox and the control has the converter declared in it's resources:

为什么不将数据加载到预加载的列表框中并使用 ItemsSource 绑定到从您的文件加载的集合?并使用可见性转换器来显示/隐藏日期.您正在做的事情对于它实际所做的事情来说似乎不必要地复杂.

Why not instead load the data into a preloaded listbox and use ItemsSource to bind to a collection loaded from your file? And use a visibility converter to show/hide date. What you're doing seems needlessly complicated for what it actually does.

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