How can we bind dynamic options in a dropdown field in Elsa 3.5.2?

[vineshvinnu]

Does anyone know how to bind dynamic options to a dropdown field in Elsa 3.5.2? I’m trying to populate the field values from the database, but I’m not sure which approach is supported in this version. Any guidance or examples would be appreciated.

[Nekrosis1]

You can create a class, inherit from DropDownOptionsProviderBase and override GetItemsAsync.
You can add whatever logic you want to produce your input.
You can add your options provider to an input by setting it in the [Input] attribute with
UIHandler = typeof(YourCustomDropdownProvider)

I noticed, that this gets evaluated once for the client, so if your data changes during use, you may need to Ctrl+F5 to get the new list.

[ldc999]

I want to create two custom activities. For example, activity A has three static dropdown options, and activity B's dropdown options are based on the selected option in activity A. This process is implemented at design time. How do I write the code in activity B?

[jsuutari]

I've got a similar need; I would like to update input's default value based on the value in different input

[sfmskywalker]

What is supported in the current codebase is a custom dropdown options provider.

The relevant pieces are:

• DropDownOptionsProviderBase in elsa-core/src/modules/Elsa.Workflows.Core/UIHints/Dropdown/DropDownOptionsProviderBase.cs
• activities using UIHandler = typeof(...) with a dropdown provider, e.g. HttpContentTypeOptionsProvider

So the first reply in this thread is directionally correct: for a dynamic list loaded from your own source, you can implement a custom DropDownOptionsProviderBase and point the input's UIHandler at it.

However, for the follow-up scenario where dropdown B depends on the value selected in dropdown A at design time, I do not see a built-in cascading-dropdown experience in the current Studio component.

Why I say that:

• the core provider base has an optional RefreshOnChange flag,
• but the current Blazor Studio dropdown component reads the select list in OnInitialized() and renders from that (elsa-studio/src/modules/Elsa.Studio.UIHints/Components/Dropdown.razor.cs).

So for Elsa 3.5.x, my reading is:

• dynamic dropdowns from code/data source: yes,
• dependent/cascading dropdowns in the stock designer: not as a built-in feature that I can point to.

If you need B to react to A in the designer, that likely needs a custom editor/UI extension rather than only a dropdown options provider.

[sfmskywalker]

Closing this as answered. Current support is a custom DropDownOptionsProviderBase for dynamic lists, while cascading design-time dropdowns still do not appear to be a built-in capability of the stock Studio editor.