Matlab 2009b & .NET

Question

I am having all sort of trouble with [FlagsAttribute] enums in Matlab. It appears there is no way to pass a combination of values as a parameter to .NET. For example, BindingFlags.Public|BindingFlags.Instance, once you combine these together in Matlab they become of an internal type and cannot be cast back to BindingFlags.

Things like

import System.*;
import System.Reflection.*;

flags = BindingFlags.Public+BindingFlags.Instance;
enum  = Enum.ToObject(Type.GetType('System.Reflection.BindingFlags'), int32(flags));

or

enum = Enum.Parse(Type.GetType('System.Reflection.BindingFlags'), 'Public, Instance');

simply don't work as it reads:

??? One or more output arguments not assigned during call to "System.Enum.ToObject" (or "System.Enum.Parse").

On the other hand

enum = Enum.Parse(Type.GetType('System.Reflection.BindingFlags'), 'Public');

works just fine and returns <1x1 System.Reflection.BindingFlags> set to 'Public'.

That goes, needless to say, for all [FlagsAttribute] enums.

Am I missing something here? Writing a C# reflection enum wrapper for Matlab is not a big deal but that would slow things down enormously. Any workaround would be deeply, deeply appreciated.

Answer 1

(This isn't an answer, just more information)

At the time of writing, the latest version of MATLAB(2010b) does not provide a .NET interface that lets you work with flag enumerations.

One of the fundamental pieces of .NET that MATLAB does not support is casting. This means a line of code like this:

myControl.Anchor = (AnchorStyles)(AnchorStyles.Top | AnchorStyles.Bottom)

Cannot be written in MATLAB.

The .NET method System.Enum.Parse would be ideal for solving the problem of creating combined flags enumerations in MATLAB. But, when invoked from MATLAB, System.Enum.Parse is broken.

Try this:

>> NET.addAssembly('System.Windows.Forms');
>> anchorStylesTypeName = 'System.Windows.Forms.AnchorStyles, System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089';
>> anchorType = System.Type.GetType(anchorStylesTypeName);
>> enum = System.Enum.Parse(anchorType, '1')

enum = 

   Top
>> 
>> % That looked good!
>> enum = System.Enum.Parse(anchorType, '2')

enum = 

    Bottom
>>
>> % OK, now we combine them...
>> enum = System.Enum.Parse(anchorType, '3')
??? One or more output arguments not assigned during call to
"_class_dot_paren".

The same function works fine when run in C#: Passing "3" to System.Enum.Parse returns "Top, Bottom".