Currently I am defining my grid columns manually in the designers. Could you let me know how you go about the grid columns automatically.

If you have a copy of 1001 Things You Wanted to Know About VFP there is an Industrial Strength grid builder in Chapter 6. It is a modified version of the native VFP grid builder that sizes the columns correctly for the underlying data, lets you use you own custom text box classes in the grid columns automatically, and renames the columns and all the contained controls appropriately for the underlying data.