Error Not able to select Related Attributes for a Drop Down input element

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Hi community, I am new with Mendix, and following currently the course Become a Rapid Developer  https://academy.mendix.com/link/paths/31/Become-a-Rapid-Developer The course is easy to follow, very detailed, but I am not able to select any Related Attributes (Course Name) at “ 4.8.2 Using Drop Down Widget ”, see printscreen below,  as being instructed, (as far as I understand point 7 of the Instruction/Explanation).   Desired outcome :  able to create a training event with 3  input Drop Down variables (Location, Teacher, Course) plus the Start and End Date, (the last two are set up in the Training Event entity) I have reread the instructions several times, even retake the whole excercise again in a new app, nothing is said about not being able to select related Attributes for a Drop Down Widget.   I set up the data model exactly as instructed, see below. Could you suggest what might be the issue here or what I should be doing ? Thanks in advance for your help !!   Course Instruction to add an Input Drop Down Widget Error: not being able to select Related Attributes Existing Data Model
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7 answers
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I was able to figure out a way but not ideal, while selecting dropdown attribute by default Mendix Studio will not provide attributes of Course or related objects, Steps to workaround

  1. Click on Create new attribute under Course, enter the new attribute name as Title1
  2. It will allow to associated ..Course/Title1, once you added this click on attribute again now you will see all attributes under course
  3. Change it by selecting Title which was association you wanted to establish
  4. Visit Domain model and delete Title1
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Hi Jan,

If I understand correctly, you’re trying to display the course name in your page. If that’s the case, you need to use a reference selector (which is used for associations). You would have to do the same thing for location and teacher as they are also connected to the training event via an association.

Dropdown is used for enumerations etc but not associations.

 

EDIT – It seems Studio has option of Dropdown only (whereas in Studio pro you’ve the possibility to add a reference selector from the input widgets). I did try in the Studio and what you just need to do is select one of the options from the entities connected to training event (in this case course), click the attribute that you want to display and it should work. Detailed steps are listed below

Sample domain model that I used:

  1. On the page → Add a data view tied to Training Event and inside the dataview add a dropdown which should now look as following:

  1. Once you do that click on the 3 blue dots and a screen will open up such as below, 

  1. Select Entities connected to training event and finally select the title 

 

  1. Your result will look something like below:

Hope this helps!

Regards,

Radhika

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Hi Jan,

Did you save your domain model changes?

If so then you should be able to follow the steps. Look closely at the screenshots that I’ve attached, I’ve actually done them in Studio. To keep it short, I’ve just taken your image, you need to click on one of the arrows as denoted by the orange arrows in the below image. Once you do that you’ll get a list of the attributes of that entity. Let’s assume that you chose Course, then you would get another screen where you would see the options for the attributes stored in the Course entity, you then need to make a selection for instance title and it should work.

If you alternatively want to do it in Studio pro just→ you will have option to add widget on the page → search for reference selector and it should look something like:

 

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Hi @Radhika Wagle,

Thanks for your response !

I am trying to create an input schedule for  Training Events,  whereby input should contain of a unique combination of  Location, Teacher and Course  , together with a Start and End Date, given the Data Model as pictured.   

So far the Training Event has only Start date and End Date.

Where to find the Reference Selector (sorry to ask) ? How to get an list of locations/teachers/courses, to be able to select an input?

Kind regards, Jan vd Wind

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Hi @Radhika Wagle,

Your explanation including pictures:  “ EDIT – It seems Studio has option of Dropdown only (whereas in Studio pro you’ve the possibility to add a reference selector from the input widgets). I did try in the Studio and what you just need to do is select one of the options from the entities connected to training event (in this case course), click the attribute that you want to display and it should work. Detailed steps are listed”

(Above is exactly according the instructions in the course.)

Doing so, the Entity “Course” appears, but I am not able to select any attribute like “Title”,  they simply do not appear ???? I can only create NEW attributes. (I work in Mendix Studio, with the data model as I pictured above)   What is missing here ?

What is the menu path for  “a reference selector”  and the toolbox and properties in Mendix Pro ? 

Kind regards, Jan van der Wind

 

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Radhika Wagle

Thanks for your patience !

 

For some weird reasons,  I can NOT select an attribute in Mendix Studio as you explained.

When I load the model in Mendix Studio Pro,  and add the Reference Selector, it works fine, including input with Web Preview. 

However if I go back to Mendix Studio, the Reference Selector widget is not there, so no synchronization.

How is it possible that Mendix Studio does not provide this input selection with me (as it should be working, yes ?)?

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Radhika Wagle  thanks for your extensive help and guidance.  Weird that mutations in Studio Pro did not synchronise in Studio in my situation.

Strange that the synchronisation of Studio Pro, where I added a working drop down, to Studio also did not work. . .

The selection of related attributes for the dynamic header of a drop down  works .. 

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