need alittle help with a check box

[Jon123]

I have this code on a text field

Me.step205.Locked = Not IsNull(Me.step205)

If the step205 has data when the form opens its locked and cant be edited.
this is what I want so now if step205 was a checkbox field
how would I write the Not Isnull part of the code?

thanks
looking

jon

 

[rainman89]

if yourcheckboxname=true then 
lock the field
else
end if

 

[seopositive2]

if Me.step205.Locked = Not IsNull(Me.step205) = true then
lock the field
else
end if