/// <summary>
/// Makes a association between an element and a native element class.
/// </summary><remarks>
/// In case of an already created object the object is returned instead of creating a new one.
/// This class returns <see cref="System.Web.UI.Control">Control</see>, but all element classes internally
/// used are using IElement, too. So in any case an internal HTML element object is being retrieved, it's
/// possible to cast to IElement instead. In case of a plug-in this is not required, because plug-ins may handle
/// their elements differently and such a cast is not appropriate. Consult the documentation of the plug-in to
/// understand the requirements for object handling.
/// </remarks>
/// <param name="el">The element for that a native object is needed.</param>
/// <returns>System.Web.UI.Control if creating or retrieving was successful, otherwise <c>null</c>. The caller is responsible to cast to the right class type.</returns>
public Control CreateElement(Interop.IHTMLElement el)
{
if (el == null)
{
return(null);
}
Type type = null;
Control element = null;
// each element will be stored in a hashtable to increase performance, subsequent calls
// to this factory will retrieve stored objects instead of creating new ones.
string uniqueName;
((Interop.IHTMLUniqueName)el).uniqueID(out uniqueName);
// look whether we have it already in the designer
if (designerHost[uniqueName] is Control)
{
Control returnEl = designerHost[uniqueName] as Control;
if (returnEl is IElement)
{
((IElement)returnEl).HtmlEditor = this.htmlEditor;
}
return(returnEl);
}
// if not, try plug-ins, and finally add
try
{
// get tag name
type = GetElementType(el);
ConstructorInfo cinfo;
if (type != null)
{
// default ctor
cinfo = type.GetConstructor(BindingFlags.Instance | BindingFlags.NonPublic, null, new Type[] { typeof(Interop.IHTMLElement), typeof(IHtmlEditor) }, null);
// not found - get it from plug-in
if (cinfo == null)
{
// probably an plugin-driven control, plug-ins register their elements in designer host
foreach (IComponent icomp in designerHost.Container.Components)
{
IDesigner id = designerHost.GetDesigner(icomp);
if (id == null)
{
continue;
}
if (id is ControlDesigner)
{
IHtmlControlDesignerBehavior db = ((ControlDesigner)id).Behavior as IHtmlControlDesignerBehavior;
if (db != null && db.DesignTimeElement.Equals(el))
{
element = icomp as Control;
break;
}
}
}
}
else
{
// usually, we get and invoke here
element = (Control)cinfo.Invoke(new object[] { el, htmlEditor });
}
// still not found, try other ctors plugins- could usually define
while (element == null)
{
//throw new NotSupportedException("Element " + ns + ":" + str1 + " not supported. Did you miss a registration?");
cinfo = type.GetConstructor(new Type[] { typeof(Interop.IHTMLElement), typeof(IHtmlEditor) });
if (cinfo != null)
{
element = (Control)cinfo.Invoke(new object[] { el, htmlEditor });
break;
}
cinfo = type.GetConstructor(new Type[] { typeof(IHtmlEditor) });
if (cinfo != null)
{
element = (Control)cinfo.Invoke(new object[] { htmlEditor });
break;
}
cinfo = type.GetConstructor(Type.EmptyTypes);
if (cinfo != null)
{
element = (Control)cinfo.Invoke(null);
break;
}
}
}
}
catch
{
// whatever is goind wrong we don't care, returning null is "bad state" for caller
//return null;
throw;
}
finally
{
if (element != null)
{
if (element is IElement)
{
((IElement)element).HtmlEditor = this.htmlEditor;
}
// not there, then we add it
if (designerHost[uniqueName] == null)
{
designerHost.Add(element, uniqueName);
((HtmlEditor)htmlEditor).OnElementCreated(element);
}
}
}
return(element);
}