Scope of 'this' operator

hello i have a class which stores the mouse x and y positions. i m having problem in accessing the variables of the class from the events inside the class

[color=#878787]// controller.as
[/color]class controller{
public [color=#000087]var[/color] x:[color=#000087]Number[/color];
public [color=#000087]var[/color] y:[color=#000087]Number[/color];
public [color=#000087]var[/color] mouse_listener:[color=#000087]Object[/color]=[color=#000087]new[/color] [color=#000087]Object/color;

public [color=#000087]function[/color] controller(){ [color=#878787]// constructor
[/color]mouse_listener.[color=#000087]onMouseMove[/color]=[color=#000087]function/color{
[color=#000087]this[/color].x=[color=#000087]_root[/color].[color=#000087]_xmouse[/color];
[color=#000087]this[/color].y=[color=#000087]_root[/color].[color=#000087]_ymouse[/color];
}
[color=#000087]Mouse[/color].[color=#000087]addListener/color;
}
}

[color=#878787]// code for controller.fla
[/color][color=#000087]var[/color] c:controller=[color=#000087]new[/color] controller();

[color=#000087]_root[/color].[color=#000087]onMouseDown[/color]=[color=#000087]function/color{
[color=#000087]trace/color;
}

[color=#878787]//outputs “undefined undefined” whenever the mouse is clicked on stage
[/color]

my problem here is i am not able to access the variables x and y of the controller class. when i try to access them from the constructor the this.x and this.y seems to refer to the mouse_listener object. i am not able to update the values to the x,y variables of the class. how do i do this ?

help please !!