It will be true is the string is either null or empty. (because in Excel both are the same thing, you can't have an empty string that is not null as you can have in C#
The syntax here is mostly the same as in Excel formulas (as they use the same parser); the same way you can't enter =if(a1=;"a";"b") you can't enter an <#if either.
I had figured out. Ofcourse it is always the case after you ask the question. I didnt know you can use the isblank as part of the tms if statement without using evalulate. Thats a nice to know.