beforeShow
fires before a control is shown
beforeShow: (value: undefined) => boolean | void;
Parameters:
value: undefined
- the current value of the control, null
Returns:
Return false
to prevent a control from being shown; otherwise, true
.
Example
form.getItem("spacer").events.on("beforeShow", function(value) {
console.log("beforeShow", value);
return true;
});