>if vartype(thisform.command1) == "O"
>** object exists
>endif

I thought so too, until yesterday I ran some code that looked like this:

IF VARTYPE(Thisform) = T_OBJECT AND Thisform.lSomething

VFP gave me a Thisform is not an object error. Supposedly VFP doesn't evaluate the second expression on an AND if the first is false, and if that's the case VARTYPE isn't always reliable, at least with respect to thisform.

Rather than the ISNULL check mentioned above, for all VFP classes, you can use

IF TYPE("Object.Name") = "C" or if you prefer the VFP constants IF TYPE("object.name") = T_CHARACTER.