WPF: FixedDocument in Visual Studio 2008 Designer

问题:

It's a well-known bug that Visual Studio shows an error when you try to construct a FixedDocument in XAML. For example, the following snippet

<DocumentViewer>
    <FixedDocument>
        <PageContent>
            <FixedPage Width="21.0cm" Height="29.7cm">
                <TextBlock>Hello World!</TextBlock>
            </FixedPage>
        </PageContent>
    </FixedDocument>
</DocumentViewer>

compiles and runs perfectly fine, but Visual Studio shows an error in the error list (Property 'Pages' does not support values of type 'PageContent'.) This is quite annoying.

I'm looking for a solution that allows me to construct my documents in a XAML file in Visual Studio without getting that error message. I've found a workaround, which I'd like to share below as an answer, but I'm curious if there's a better (more elegant) solution around.

回答1:

I know this had already been answered, but I think this answer is nicer because it doesn't require you to add a DocumentView.

If there's a way to reference the resources by the key name and put them in the FixedDocument with XAML, please let me know. I can't seem to find a way to do that, but maybe it's possible.

Use:

var doc = System.Windows.Application.LoadComponent(new Uri("/FixedDocumentExample.xaml", UriKind.Relative)) as FixedDocument;
doc.AddPages();

Extension Method:

using System.Collections;
using System.Windows.Documents;

public static class FixedDocumentExtended {
    public static void AddPages(this FixedDocument fixedDocument) {
        var enumerator = fixedDocument.Resources.GetEnumerator();
        while (enumerator.MoveNext()) {
            var pageContent = ((DictionaryEntry)enumerator.Current).Value as PageContent;
            if (pageContent != null) {
                fixedDocument.Pages.Add(pageContent);
            }
        }
    }
}

XAML:

<FixedDocument
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <FixedDocument.Resources>
        <PageContent x:Key="page1">
            <FixedPage Width="793.76" Height="1122.56">
                <TextBlock Margin="50" Text="Page 1"/>
            </FixedPage>
        </PageContent>
        <PageContent x:Key="page2">
            <FixedPage Width="793.76" Height="1122.56">
                <TextBlock Margin="50" Text="Page 2"/>
            </FixedPage>
        </PageContent>
    </FixedDocument.Resources>
</FixedDocument>

回答2:

As a workaround, I put the DocumentViewer as well as the page into a grid:

<Grid>
    <FixedPage Width="21.0cm" Height="29.7cm" x:Name="uiPage1">
        <TextBlock>Hello World!</TextBlock>
    </FixedPage>
    <DocumentViewer>
        <FixedDocument x:Name="uiReport">
        </FixedDocument>
    </DocumentViewer>
</Grid>

Then I attach the page to the DocumentViewer in the Loaded event of the window:

VB example:

DirectCast(Me.uiPage1.Parent, Grid).Children.Remove(Me.uiPage1)
Dim content As New PageContent()
DirectCast(content, IAddChild).AddChild(Me.uiPage1)
Me.uiReport.Pages.Add(content)

C# example:

((Grid)uiPage1.Parent).Children.Remove(uiPage1);
var content = new PageContent();
((IAddChild)content).AddChild(uiPage1);
uiReport.Pages.Add(content);

回答3:

A cleaner workaround:

[ContentProperty("Pages")]
public class XamlFixedDocument : FixedDocument
{
    private ObservableCollection<PageContent> _pages;

    public XamlFixedDocument()
    {
        this.Pages = new ObservableCollection<PageContent>();
    }

    public new ObservableCollection<PageContent> Pages
    {
        get => _pages;
        set
        {
            _pages = value;

            foreach (var page in _pages)
            {
                base.Pages.Add(page);
            }

            _pages.CollectionChanged += (o, e) =>
            {
                if (e.NewItems != null)
                {
                    foreach (PageContent page in e.NewItems)
                    {
                        base.Pages.Add(page);
                    }
                }
            };
        }
    }
}

This subclass of FixedDocument fakes a Pages property and redirect all added pages to the real Pages property in its base class.

Usage:

<doc:XamlFixedDocument xmlns:doc="clr-namespace:Hillinworks.WPF.Document">
    <PageContent>
        <FixedPage Background="White">
            <TextBlock Text="hello, world" />
        </FixedPage>
    </PageContent>
</doc:XamlFixedDocument>

Change Hillinworks.WPF.Document to the namespace where the XamlFixedDocument class is located.

This also enables design-time preview of your document.