//// Steps for resolving a ViewModel to View
//// 1. Find all ViewModel requested Views matching the ControlKind
//// 2. Find all Views supporting the ViewModel matching the ControlKind
//// 3. Find all Views supporting the ViewModel without ControlKind
/// <summary>
/// Look up the ViewDescriptor for this presentable model and ControlKind
/// </summary>
/// <param name="self"></param>
/// <param name="tk"></param>
/// <param name="requestedControlKind"></param>
/// <returns></returns>
public static ViewDescriptor GetViewDescriptor(
this ViewModelDescriptor self,
Toolkit tk,
ControlKind requestedControlKind)
{
// Checks
if (self == null)
{
throw new ArgumentNullException("self");
}
#region Cache Management
PrimeCaches(tk, self.ReadOnlyContext);
var key = new ViewDescriptorCache.Key(self.ViewModelRef, tk, requestedControlKind);
if (_viewDescriptorCache.ContainsKey(key))
{
return(_viewDescriptorCache[key]);
}
#endregion
// If the ViewModel has a more specific DefaultKind respect its choice
if (self.DefaultEditorKind != null &&
requestedControlKind != null &&
self.DefaultEditorKind.AndParents().Select(i => i.ExportGuid).Contains(requestedControlKind.ExportGuid))
{
if (requestedControlKind != self.DefaultEditorKind)
{
Logging.Log.DebugFormat("Using more specific default kind: {0} -> {1}", requestedControlKind.Name, self.DefaultEditorKind.Name);
}
requestedControlKind = self.DefaultEditorKind;
}
else
{
requestedControlKind = self.SecondaryControlKinds
.FirstOrDefault(
sck => sck.AndParents()
.Select(i => i.ExportGuid)
.Contains(requestedControlKind.ExportGuid)
) ?? requestedControlKind;
}
ViewDescriptor result = null;
ICollection <ViewDescriptor> candidates;
if (requestedControlKind != null)
{
candidates = _viewCaches[tk].GetDescriptors(requestedControlKind);
}
else
{
candidates = _viewCaches[tk].GetDescriptors();
}
if (candidates.Count == 0)
{
// Try parent
var parent = self.ViewModelRef.Parent != null?self.ViewModelRef.Parent.GetViewModelDescriptor() : null;
if (parent != null)
{
result = GetViewDescriptor(parent, tk, requestedControlKind);
}
else
{
Logging.Log.WarnFormat("Couldn't find ViewDescriptor for '{1}' matching ControlKind: '{0}'", requestedControlKind, self.ViewModelRef);
}
}
else if (candidates.Count == 1)
{
result = candidates.First();
}
else
{
var allTypes = GetAllTypes(self);
// As allTypes is sorted from most specific to least specific first or default is perfect.
var match = allTypes.SelectMany(t => candidates.Where(c => c.SupportedViewModels.Contains(t))).FirstOrDefault();
// Try the most common
if (match == null)
{
match = allTypes.SelectMany(t => candidates.Where(c => c.SupportedViewModels.Count == 0)).FirstOrDefault();
}
// Log a warning if nothing found
if (match == null)
{
Logging.Log.WarnFormat("Couldn't find ViewDescriptor for '{1}' matching ControlKind: '{0}'", requestedControlKind, self.GetType().FullName);
}
result = match;
}
_viewDescriptorCache[key] = result;
return(result);
}
