>

>theFld=thisform.edtReplaceFld.value && "trimzero(StNumExt)"
>theType=type(m.theFld)

&& Returns U
>
>I dont' think, I can use & or evaluate function here...

IMO, you can't avoid traping the error in this case (via ON ERROR, or Error method)

theFld=thisform.edtReplaceFld.value && "trimzero(StNumExt)"
ON ERROR m.VarToCheck = Null
m.VarToCheck = eval(theFld)
ON ERROR   && whatever was before
? vartype(m.VarToCheck)  && this will not fail

If you want a more elegant solution, define an "evaluator" class with error control, and use

oEvaluator = createobject("Evaluator")
m.VarToCheck = oEvaluator.Eval(theFld) && avoids placing ON ERROR in each evaluation
? vartype(m.VarToCheck)  && this will not fail

Regards,