problem displaying axis values in flex chart

I have a value object 开发者_运维知识库something like this

public class Data
{

    public var date:Date;
    public var value:int;

            ...

    public function get formattedDate():String
    {
        return date.getDay()+"."date.getMonth()+"."+date.getYear();
    }

}

When I use the 'date' field for the category axis everything is fine but when I change that to the 'formattedDate' it doesn't work (the axis has no labels). Any ideas why this isn't working?

Watch types.

When you use date you get Number type result.

When you use formattedDate you get String type result.

You have to return Number type also using formattedDate.