Passing combobox value to custom class

Hi all,

I have created a class that populates a combobox list with my values for reuase, this class is then initialised in a user form and linked to a combobox1.

However, I'm trying to generate a couple of properties from the selection of this list made by the user.

So, to try and explain again, the list is created by a class, the user clicks on the drop down and selects a value in the list, I then wnat the class to know which value is selected so that I can do calculations in the class.

How do I do this?

Here is my code:

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In the class

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In the form

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Now when changing a value in the combobox the class variable cb_value will hold the selected value

The class object already knows.

Within the class object

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And you can use the events of the m_cmbFlangeSection object to code against.

Hi Andy, what would my new code look like?

Your code:

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As you have declared the reference in the class as public you can use the following in your userform

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If it had been a private member of the class you could add a property to the class

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Userform code

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Is the sole purpose of this to populate a list with fixed values? If so a simple function would have done.

Hi Andy

Sorry but I'm not getting it to work.

Here is how I have applied your code to my code:

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I'm getting a run-time 91 error on:

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Hi Steffen,

I'm also not able to get your code to work, not sure why.

It's really not clear why you are doing this.
It's also very confused code.

You have declared the object m_cmbFlangeSection but then not used it, which is the reason for my code error.

When I change the reference in the class and modify the userform code it works.

I've removed the line where you declare a new instance of the object.
Value is not a property available for generic msforms.Controls.

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But the issue now is why the class when you are coding against the combox events on the userform. As I said if all you want to do is load the control with a static list use a function in a standard code module. Or as Romperstomper suggested originally read the information from a file.

The combobox is used in a Engineering form. The user selects a value in the combobox and then the class goes through a series of calculations, calculating the running mass (kg/m), the paint area (m²), etc. These properties are then returned to the user form for further calculations.

The custom combo, just like some of the others I am/ will be working on, is to be used on various types of Engineering forms, each calculating something else. The excel file (before the user uses it) will be a template file, stored under our templates folder, and then when changed into a normal .xlsm file, be moved to the relevant project folder.

The reason why I dont want to have the combobox reference to a stand-alone file, is that, if the structure of our system changes, or we realise that our designs are not optimum and we then decide to change the design calculations, it will influence existing designs, and I'd like to keep what we have designed at a specific time, to remain as is, no matter what other decision is later made.

As for the code change you suggest, I'll try now to see if it works.

So you need to move your calculation code into the class code using the events of the object your declared but as yet are not using.

There should be no need for code in the combobox on the user forms events.

Once you have done the class level calculations you can raise your own events in the class and capture those in the userform.

Damn it is nice to talk to the experts, and sorry for not quit explaining what I want to achieve in words that all can understand.

How would I achieve this?

I would for instance take the selection and split the string, remove what is standing in the front, and split at the "x", giving me three values, these I would use in calculations.

class code

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Userform code

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Thanks for the reply Andy, it seems to do something like what I'd like to achieve, I'm going off-line for a bit (work is calling), but I will post again in this thread, even if it is just to say SOLVED...

Thanks again.

Morning guys,

So I have made a couple of adjustments, and it works perfectly, thank you very much.

Here is the final code as I will be using it in my forms:

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For now I'll say this is solved, but if anyone can point out if I can "clean up" my code, please feel free to do so.

Instead of private variables in the userform why not keep all those flange values within in the class itself and expose them as properties, maybe even read-only properties.
You could then remove them from the FlangeCalc event signature.

How would I do this? Sorry Andy, I'm very new to the concept of classes

See attached.

I made 1 of the properties read/write by including both Get/Let properties. The others are read-only.

That is fantastic!!! It makes the code I require in my form so much less.

So the flangeHeight is the read-write one, but what does RHS stand for?

It's a coding style I picked up from the PED book.

RHS - RightHandSide

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So if I want the height to be read-only, I simply remove the let sub()?

I was wondering if there are books available for more advanced programming...

Yes. For a property

Get & Let = Read/Write
Get only = Read only
Let only = Write only

You can not beat the book in the link.

Thanks a million

This thread is then SOLVED.

Thanks to all.