实际上用状态破折号app.long_callback参数

Question

@app.long_callback(
    outputs = Output("optimize-result", "children"),
    inputs = Input("optimize-button-id", "n_clicks"),
    states = dict(
        reorder_period = State("reorder-period-dropdown-id", "value"),
        forecast = State("forecast-dropdown-id", "value")
    ),
    running = [
        (Output("optimize-button-id", "disabled"), True, False),
    ],
    prevent_initial_call = True,
)
def load_optimize_data_button_click(number_clicks, reorder_period, forecast):

怎么能解决这个问题。它导致了一个TypeError: load_optimize_data_button_click() missing 2 required positional arguments: 'reorder_period' and 'forecast'

对于正常的回调，请参见以下内容：

@app.callback(
    Output("optimize-result", "children"),
    Input("optimize-button-id", "n_clicks"),
    State("reorder-period-dropdown-id", "value"),
    State("forecast-dropdown-id", "value"),
    prevent_initial_call = True,
)
def load_optimize_data_button_click(number_clicks, reorder_period, forecast):

我遇到了麻烦，因为我找不到app.long_callback使用的参数的api文档。

Answer 1

您可以简单地使用：

@app.long_callback(
    output=Output("optimize-result", "children"),
    inputs=dict(number_clicks=Input("optimize-button-id", "n_clicks")),
    state=dict(
        reorder_period=State("reorder-period-dropdown-id", "value"),
        forecast=State("forecast-dropdown-id", "value")
    ),
    running=[
        (Output("optimize-button-id", "disabled"), True, False),
    ],
    prevent_initial_call=True,
)
def load_optimize_data_button_click(number_clicks, reorder_period, forecast):
    pass

首先，根据文档，使用state而不是states。其次，输入和状态的数据类型显然都需要相同，要么两者都是list，要么是dict。

上面的代码与Dash 2.0.0一起工作。希望这会有所帮助:)

Answer 2

@app.long_callback(
    Output("optimize-result", "children"),
    Input("optimize-button-id", "n_clicks"),
    [State("reorder-period-dropdown-id", "value"),
     State("forecast-dropdown-id", "value")],
    running=[
        (Output("optimize-button-id", "disabled"), True, False),
    ],
    prevent_initial_call = True,
)