A memory leak in RadPdfViewer when the control gets removed from the visual tree.
To work this around, use the reflection API to access the leaking VisualTarget objects and call their Dispose method manually.
var pdfViewer = hostBorder.Child as RadPdfViewer;
if (pdfViewer != null)
{
var canvas = viewer.ChildrenOfType<Canvas>().FirstOrDefault(x => x.GetType().Name.Contains("ContentElementsCanvas"));
var visualTargetsDictionaryField = canvas.GetType().GetField("pageNumberToVisualTarget", BindingFlags.NonPublic | BindingFlags.Instance);
var visualTargetsDictionary = (Dictionary<int, List<VisualTarget>>)visualTargetsDictionaryField.GetValue(canvas);
foreach (KeyValuePair<int, List<VisualTarget>> target in visualTargetsDictionary)
{
for (int i = 0; i < target.Value.Count; i++)
{
VisualTarget item = target.Value[i];
item.RootVisual = null;
item.Dispose();
}
}
}
hostBorder.Child = null;
hostBorder.Child = new RadPdfViewer() { Document = newDocument };
When importing a document containing a single associated widget annotation merged into the field dictionary the field is skipped on import and an exception is thrown.
According to the PDF Specification: Field Dictionaries: Kids:
An array of indirect references to the immediate children of this field.
In a non-terminal field, the Kids array is required to refer to field dictionaries that are immediate descendants of this field. In a terminal field, the Kids array ordinarily must refer to one or more separate widget annotations that are associated with this field. However, if there is only one associated widget annotation, and its contents have been merged into the field dictionary, Kids must be omitted.
As a result, the glyphs are not measured and positioned properly. The issue applies to the TrueType and Type1 fonts.