flex 4 datefield不会调度清除事件

<mx:DateField id=\"date\" 
    formatString=\"DD-MM-YYYY\" selectableRange=\"{DTselectableRange}\" 
    change=\"handleChange()\" editable=\"true\"  clear=\"dateCleared(event)\"/>

clear

mx.controls.TextInput

spark.components.TextInput

clear

handleChange

selectedDate

private var selectedDate:Date;

private function handleChange(date:Date):void {
    if (date == null) {
        selectedDate = null;
    }       
    // your existing handleChange code here
}

<mx:DateField change=\"handleChange()\" />

<mx:DateField change=\"handleChange(DateField(event.target).selectedDate)\" />