Populate drop down menus with enums

Hello all,

I trying to understand enumerations and how they are to be used in matlab. I have 2 questions:

1.: In C# I can just define enums in a class:

enum someSpecificValues { one = 1, two = 2, three = 3 }:

And later use them

var enumTest = someSpeficValues.one;

Now, what I understood from the MATLAB help is that I need to define each enum as a class and then call that from within my class. I am developing a driver library, where I need a couple of settings as enums. Do I really need to define them in that way or is there a way to define them within the class? Creating them inside the class has the added advantage that they're confined to the class, where they make sense.

2.: Along with my driver I'd like to create some examples in the app creator, where I want to display these enumerated values as drop down menus, so people don't just enter random values. Is there a way to link the drop down to the enumeration or would I have to write the values by hand and hope not to make an error? Again, in C# you could bind the drop down to the enum (technically, you'd bind to the list, but the effect is the same) and changes to the enum would be reflected on your UI.

I have tried to use the DropDown.Items property and realized this accepts string arrays and not enumerations. I don't know how to correctly convert my enumeration, though. Suppose I have the class:

classdef readModes
    enumeration
        ZIF, SH, SHN, HDR, DD
    end
end

Then the following would not work.

app.DropDown.Items = enumeration(readModes.ZIF);

But what does?

[Peter Foerster]

Does no one have an idea?

I have an additional question:

How can I pass the enums to a function as an input parameter? Suppose I have the readModes from above.

In my main class I have a function:

function return = setMode (<readMode enum>)
end

How do I have to define <readMode enum> so, the function accepts an enum as the input argument and doesn't accept invalid values?

Answer 1

[Peter Foerster]

OK, here's what I figured out so far:

1.: Yes, I do. I still don't agree with this way of doing things.

2.: What I did now, is create some arrays to fill the drop downs from in my driver class. This is not a very elegant way, as it's not self-maintaining, but it does solve my secondary problem, where I need a subset of the enum values for another example.

Using the enumeration from above, created these arrays in my class:

modes = [readModes.SH readModes.SHN];
modeStrings = ["SH" "SHN"];

And in my app, I could populate them as:

app.DropDown.Items = app.wsaInterface.modeStrings;
app.DropDown.ItemsData = app.wsaInterface.modes;

This should do, what I demand

3.: I haven't found a way to force the passing of the correct type, but I might do something along the lines of

if class(functioParam) == class(readModes.SH)

To check if the correct parameter has been passed.

Answer 2

[Karl Erik Thoresen]

Try:

app.DropDown.Items =   cellstr(enumeration(myClass.SomeEnum));

Answer 3

[Ben]

classdef MyClassDef

enumeration

Item1

Item2

Item3

end

methods(Static)

% create an array of enumeration item name strings

function il = itemlist()

items = ?MyClassDef;

Ni = length(items.EnumerationMemberList);

il = strings(Ni,1);

for i = 1:Ni

il(i) = items.EnumerationMemberList(i).Name;

end

end

end

end

Use the itemlist to populate the dropdown. This can be done through adding a callback - just add the following to the callback:

% Callbacks that handle component events

methods (Access = private)

% Code that executes after component creation

function startupFcn(app)

myitems = MyClassDef.itemlist;

app.MyItemsDropDown.Items = myitems;

end

end

Where MyItemsDropDown is the name you gave to the dropdown that you created in the app designer.