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fires before a control or its radio button is shown

beforeShow: (value: string, id?: string) => boolean | void;


  • value: string - the current value of the control
  • id?: string - optional, the ID of the radio button of the control


Return false to prevent a control or its radio button from being shown; otherwise, true.


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

Related sample: Form. Hide/Show control

Change log:

  • The id parameter was added in v8.0
  • The event was added in v7.0