How to change a dropdown's options based on a text field?

[failable]

I tried to update a dropdown's options by the following code, but it does not work. Is this currently supported? Thanks.

get_generic_name, set_generic_name = mo.state("")
get_specifications, set_specifications = mo.state([])
get_specification, set_specification = mo.state("")

def get_distinct_specifications(generic_name: str, *, uri: str) -> list[str]:
    if not generic_name:
        return []

    query = f"""select distinct(specification)
from drug_dosage_admin 
where generic_name REGEXP '^{re.escape(generic_name)}';"""

    df = pl.read_database_uri(query, uri=uri)

    return sorted(set(df["specification"].to_list()))


def on_generic_name_change(generic_name: str):
    set_generic_name(generic_name)
    set_specifications(
        lambda _: get_distinct_specifications(get_generic_name(), uri=database_url)
    )

    specification.options = get_specifications()


generic_name = mo.ui.text(
    get_generic_name(),
    placeholder="e.g. 布洛芬缓释片",
    label="通用名",
    on_change=on_generic_name_change,
)
specification = mo.ui.dropdown(
    get_specifications(),
    value=None,
    label="规格",
    on_change=set_specification,
)

mo.hstack([generic_name, specification], justify="start")

[akshayka]

Don't use mo.state(), and don't use on_change handlers. They should be used exceedingly rarely, and almost always lead to trouble.

You need to use marimo's built-in reactivity. Run marimo tutorial ui to understand how this works or read our docs.

Here is an example:

Notebook link: https://marimo.app/l/vfwyu0

Out of curiosity, how and why did you decide to use mo.state and on_change? I would really strongly like to discourage users from doing this.