public override DataTemplate SelectTemplate(object item, DependencyObject container)
{
if (item == null)
{
return(base.SelectTemplate(item, container));
}
DataTemplate template = null;
if ((item is byte[]) || (item is System.Drawing.Image))
{
bool useImageTemplate = false;
try
{
var converter = new ImageConverter();
useImageTemplate = (converter.Convert(item, typeof(ImageSource), null, CultureInfo.CurrentCulture) != null);
}
catch (NotSupportedException)
{
//suppress the exception, the byte[] is not an image. convertedValue will remain null
}
if (useImageTemplate)
{
template = GenericContentTemplateSelector.GetImageTemplate(container);
}
}
else if (item is ImageSource)
{
template = GenericContentTemplateSelector.GetImageTemplate(container);
}
else if (item is bool)
{
template = GenericContentTemplateSelector.BoolTemplate;
}
if (template == null)
{
template = GenericContentTemplateSelector.GetCommonTemplate(item, container);
}
if (template != null)
{
return(template);
}
return(base.SelectTemplate(item, container));
}
private static DataTemplate GetCommonTemplate(object item, DependencyObject container)
{
Debug.Assert(item != null);
var itemType = item.GetType();
// Do not provide a template for data types that are already optimized by the framework or
// for data types that have a default template.
if (GenericContentTemplateSelector.IsTypeOptimized(itemType) ||
GenericContentTemplateSelector.HasImplicitTemplate(item, itemType, container))
{
return(null);
}
return(GenericContentTemplateSelector.GetDefaultTemplate(itemType));
}
private static DataTemplate GetDefaultTemplate(Type type)
{
Debug.Assert(type != null);
var converter = TypeDescriptor.GetConverter(type);
if ((converter == null) || (!converter.CanConvertTo(typeof(string))))
{
return(GenericContentTemplateSelector.CommonTemplate);
}
var templates = GenericContentTemplateSelector.DefaultTemplates;
lock ((( ICollection )templates).SyncRoot)
{
for (int i = templates.Count - 1; i >= 0; i--)
{
var target = templates[i];
var targetTemplate = target.Value.Target as DataTemplate;
// We have found the desired template.
if (target.Key == type)
{
if (targetTemplate != null)
{
return(targetTemplate);
}
// Unfortunately, the template has been garbage collected.
templates.RemoveAt(i);
break;
}
}
templates.TrimExcess();
var template = GenericContentTemplateSelector.CreateDefaultTemplate(type, converter);
templates.Add(new KeyValuePair <Type, WeakReference>(type, new WeakReference(template)));
return(template);
}
}
private static bool HasImplicitTemplate(object item, Type type, DependencyObject container)
{
Debug.Assert(type != null);
var finder = GenericContentTemplateSelector.FindTemplateResource;
if (finder == null)
{
finder = GenericContentTemplateSelector.GetFindTemplateResourceInternal();
if (finder == null)
{
finder = GenericContentTemplateSelector.FindTemplateResourceFallback;
}
GenericContentTemplateSelector.FindTemplateResource = finder;
}
Debug.Assert(finder != null);
return(finder.Invoke(container, item, type) != null);
}