Get the "handle number" of a standard handle class

How can I ...

-Get the "handle number" (like the handle number returned when using hdgetset classes(ex : 203.0024)) of a myclass object which is of a "standard" handle class (myclass<handle)

-Store this "handle number" in a text variant

-And then retrieve my original object by this "handle number"

Thanks for you help!!! Gabriel

Answer 1

[Walter Roberson]

You can attach arbitrary (binary) data to a graphics object by setting its UserData property, or by using setappdata() on it.

Answer 2

[Andrew Newell]

Setappdata seems best because of the limitations on using the UserData property (see How can I keep track of my GUI object handles?. You can store handles, as in the following example:

x = 1:10;
h = plot(x,x);
ha = @(x) x^2;
setappdata(h,'myHandle',ha)
f = getappdata(h,'myHandle');
f(2)

ans = 
    4

Answer 3

[Daniel Shub]

You cannot do this directly. I don't understand why you would want to. Why not just pass the object around? MATLAB is pretty smart about memory management and doesn't make copies of handle object every time they are referenced.

If you really want to do it, you could subclass the handle class with something like myhandle. This new class could have a public property "h" which gets set at creation with a unique number. There are a number of ways that I can think of to keep track of the handle number to guarantee that they are unique. Then just make myclass<myhandle.

[Walter Roberson]

I _think_ what Gabriel is asking for is an object serialization method. Which MATLAB does have internally but has never exposed.

[Daniel Shub]

@Walter, it is possible that I am wrong. I interpreted hdgetset to be hgsetget and the 203.0024 to be a handle to a graphics object.

[Walter Roberson]

Hard to say. We'll have to wait for an update from Gabriel.

[Gabriel Caron L'Écuyer]

I am building a mass transit simulation interface. The user use tools to build the mass transit system over an image. What I need is to make a link between the graphic objects (lines, etc.) and the "simulation objects" they represent(tracks, stations, etc.). The only way that I have found to store information into a graphic object is by changing their Tag property. The problem is that the Tag property only accept text. I don't want to store the graphic objects into my "simulation objects". If you have an alternate method to arrive to that goal, it could also solve my problem. Thanks.

[Gabriel Caron L'Écuyer]

So my question was basically if an object of class Myclass<handle have a handle that can be retrieved and used to retrieve back this object like the graphics objects have.

[Walter Roberson]

Gabriel, object handles that are not handle graphics objects, do *not* have a representation of the kind you are seeking.

Answer 4

[Gabriel Caron L'Écuyer]

Thanks, it solved my problem. Gabriel