multiple uses of attached property does not work_问答_开发者

multiple uses of attached property does not work

开发者 https://www.devze.com 2023-02-01 00:57 出处：网络

My guess is I\'m not understanding attached properties correctly.I\'m trying to convert the FlowDocument on a RichTextBox to an HTML string property in my view model.I have two RichTextBoxes that are

My guess is I'm not understanding attached properties correctly. I'm trying to convert the FlowDocument on a RichTextBox to an HTML string property in my view model. I have two RichTextBoxes that are using my RichTextBoxAssistant class (thanks to this blog post):

<RichTextBox x:Name="rtb_description" 
    local:RichTextBoxAssistant.BoundDocument="{Binding MyVM.Description,
        ValidatesOnDataErrors=True}"/>

<RichTextBox x:Name="rtb_descriptionHowTo"
    local:RichTextBoxAssistant.BoundDocument="{Binding MyVM.DescriptionHowTo,
        ValidatesOnDataErrors=True}" />

In my RichTextBoxAssistant class, I have this dependency property:

public static readonly DependencyProperty BoundDocument =
    DependencyProperty.RegisterAttached(
        "BoundDocument",
        typeof(string),
        typeof(RichTextBoxAssistant),
        new FrameworkPropertyMetadata(
            null,
            FrameworkPropertyMetadataOptions.BindsTwoWayByDefault,
            boundDocumentChanged
        )
    );

The problem is that the boundDocumentChanged method gets hit when I change the value in my first RichTextBox, rtb_description, but not when I change the value in rtb_descriptionH开发者_StackOverflowowTo. When I change the text or do anything to rtb_descriptionHowTo, I never reach boundDocumentChanged. Is this a result of RichTextBoxAssistant being a static class? How can I fix it so that I can use RichTextBoxAssistant with multiple RichTextBoxes?

ColinE had the right idea: I tried removing the attached property from my first RichTextBox, and changing the value of the second RichTextBox still didn't put me in boundDocumentChanged. Turns out my DescriptionHowTo property in my view model was null, instead of an HTML string. When I initialized it to @"<html><body></body></html>", things started working.