beforeShow

fires before a control is shown

beforeShow: (value: string | string[]) => boolean | void;

Parameters:

value: string | string[] - the id(s) of the item(s) from data collection that are currently selected in the control

Returns:

Return false to prevent a control from being shown; otherwise, true.

Example

form.getItem("combo").events.on("beforeShow", function(value) {
    console.log("beforeShow", value);
    return true;
});

Change log:

added in v7.0