>HI,
> I am building a custom combo box. I use grid to display the data . However, Iface some problem:
>
>1. If I use ADDOBJECT() to addgrid into my container, the grid may not appear because its view only limited by the size of my container.
>

Just resize the container to whatever size you want the grid to be.

>2. If I use CREATEOBJECT() to add grid and store its reference into a property, the grid doesn't appear even i have set visible = .t..

You can't do this, because you want your grid to be a member of the form/container. When you create the grid like this, it just lives in space, without a parent container. That's why it doesn't appear on your form.