Using System.Reflection to get OCAF attributes applied to a Label

OCAF tree is the highlevel structure of data that stores the data in a tree formed by number in it's nodes, and extra data named attributes.

The NaroCAD C# code to access one specific attribute may be like this:

OCTDF_Label label = ...
// Check for integer attribute for an attribute
OCTDataStd_Integer integerAttr = new OCTDataStd_Integer();
if (label.FindAttribute(OCTDataStd_Integer.GetID(), integerAttr))
{
//using integerAttr...
}

How can we get the list of attribute types are attached to a label? As we don't have a real type introspection accessible using C++ code, or to C# (like from void * to decide which type of object is added, OpenCascade itself makes this thing a bit harder too, as is C++ code and NaroCad is C# code).

What is the solution to get the list of attributes then? We can scan the OCWrappers.dll assembly and to see which class have a method: GetId and invoke it to simulate the previous code:

Assembly assembly = Assembly.Load("OCWrappers");

foreach (Type type in assembly.GetTypes())
{

try
{
MethodInfo[] mis = type.GetMethods();
MethodInfo miGetId = null;
foreach(MethodInfo mi in mis)
{
if(mi.Name == ("GetID"))
{
miGetId = mi;
}
}
if(miGetId != null)
{
OCTDF_Attribute attrPtr = Activator.CreateInstance(type) as OCTDF_Attribute;
OCStandard_GUID attrGetId = miGetId.Invoke(type, new object[] {} ) as OCStandard_GUID;
if (childLabel.FindAttribute(attrGetId, attrPtr))
{
//code that gets the attribute name which is: type.Name
}
}
}
}
catch
{
//calls may fail so we should skip missused called types
}
}

If you are curious, you may look to the NaroCad implementation which is a bit more improved as the assembly is preprocessed and cached, so only a small list of candidates will be applied to a label, and the OCWrappers assembly is not loaded before every label.