Implementation
set apply(NikuDropdownButtonFormField? v) {
if (v == null) return;
selectedItemBuilder = v.selectedItemBuilder ?? selectedItemBuilder;
hint = v.hint ?? hint;
disabledHint = v.disabledHint ?? disabledHint;
onChanged = v.onChanged ?? onChanged;
onTap = v.onTap ?? onTap;
elevation = v.elevation ?? elevation;
style = v.style ?? style;
underline = v.underline ?? underline;
icon = v.icon ?? icon;
iconDisabledColor = v.iconDisabledColor ?? iconDisabledColor;
iconEnabledColor = v.iconEnabledColor ?? iconEnabledColor;
iconSize = v.iconSize ?? iconSize;
isDense = v.isDense ?? isDense;
isExpanded = v.isExpanded ?? isExpanded;
itemHeight = v.itemHeight ?? itemHeight;
focusColor = v.focusColor ?? focusColor;
focusNode = v.focusNode ?? focusNode;
autofocus = v.autofocus ?? autofocus;
dropdownColor = v.dropdownColor ?? dropdownColor;
menuMaxHeight = v.menuMaxHeight ?? menuMaxHeight;
enableFeedback = v.enableFeedback ?? enableFeedback;
alignment = v.alignment ?? alignment;
borderRadius = v.borderRadius ?? borderRadius;
decoration = v.decoration ?? decoration;
$parent..$merge(v.$parent);
}