>I am trying to hide a column in grid.
>I have tryed by making Grid1.column1.Visible = .f.
>But, it only removes the caption of Header,
>does not remove the column from grid.

The only way to do this in VFP7 and below is to move the column to the far right of the grid and reduce the column count by one, so that it's eliminated.

>By other way, If I add column in grid, at run time.
>How can I associate my Code on the valid of some control under that column.

You need to have the code in a subclass, which you can add to the column programatically.