User-friendly way to display a Visual in a WPF application? - wpf

Question

Looking for a simple, elegant way to display any given Visual to the user. The only way I can think of off my head is to slap it in a brush and paint it on a Rectangle that's in a ScrollViewer. Not exactly the best option.

Answer 1

You could create a wrapper that inherits from FrameworkElement that would either host your Visual or a generic wrapper that will host any object deriving from Visual.
Take a look at the example in Visual.AddVisual or, if you want to host more than one visual, take a look at the (partial) example in Using DrawingVisual Objects

Answer 2

I don't see a way how you could do that since a Visual has neither a position nor a size. Perhaps stick to FrameworkElement and create a style for it?

Answer 3

My (current) answer is to slap it in an XpsDocument and display it in a DocumentViewer. I could, I suppose, do it a little less complex, but I already have the infrastructure to do it this way. Its not 100%, but it works.
First, a behavior so that I can bind to DocumentViewer.Document (its a friggen POCO, urgh):
public sealed class XpsDocumentBinding
{
#region Document
/// <summary>
/// The <see cref="DependencyProperty"/> for <see cref="Document"/>.
/// </summary>
public static readonly DependencyProperty DocumentProperty =
DependencyProperty.RegisterAttached(
"Document",
typeof(XpsDocument), //
typeof(XpsDocumentBinding),
new UIPropertyMetadata(null, OnDocumentChanged));
/// <summary>
/// Gets the value of the <see cref="DocumentProperty">Document attached property</see> on the given <paramref name="target"/>.
/// </summary>
/// <param name="target">The <see cref="DependencyObject">target</see> on which the property is set.</param>
public static XpsDocument GetDocument(DependencyObject target)
{
return (XpsDocument)target.GetValue(DocumentProperty);
}
/// <summary>
/// Sets the <paramref name="value"/> of the <see cref="DocumentProperty">Document attached property</see> on the given <paramref name="target"/>.
/// </summary>
/// <param name="dependencyObject">The <see cref="DependencyObject">target</see> on which the property is to be set.</param>
/// <param name="value">The value to set.</param>
public static void SetDocument(DependencyObject target, XpsDocument value)
{
target.SetValue(DocumentProperty, value);
}
/// <summary>
/// Called when Document changes.
/// </summary>
/// <param name="sender">The sender.</param>
/// <param name="e">The <see cref="System.Windows.DependencyPropertyChangedEventArgs"/> instance containing the event data.</param>
private static void OnDocumentChanged(object sender, DependencyPropertyChangedEventArgs e)
{
var viewer = sender as DocumentViewer;
if (viewer == null)
throw new InvalidOperationException(
"This behavior is only valid on DocumetViewers.");
var doc = e.NewValue as XpsDocument;
if (doc == null)
return;
viewer.Document = doc.GetFixedDocumentSequence();
}
#endregion
}
Then in my model I expose my visual as an XpsDocument
var pack = PackageStore.GetPackage(_uri);
if (pack != null)
return new XpsDocument(pack, CompressionOption.SuperFast, _uri.AbsoluteUri);
MemoryStream ms = new MemoryStream(2048);
Package p = Package.Open(ms, FileMode.Create, FileAccess.ReadWrite);
PackageStore.AddPackage(_uri, p);
XpsDocument doc = new XpsDocument(p, CompressionOption.SuperFast, _uri.AbsoluteUri);
var writer = XpsDocument.CreateXpsDocumentWriter(doc);
var collator = writer.CreateVisualsCollator();
// write the visuals using our collator
collator.BeginBatchWrite();
collator.Write(Visual);
collator.EndBatchWrite();
p.Flush();
return doc;
Just add a DocumentViewer, bind the result of the conversion method to it via the behavior, and there it is. I'm sure there's a shortcut in here somewhere...