I have a code -
strTest=" "
IsNull(Trim(strTest))
It returns False in VB6 .
I write this code to VB.net
but
IsNull(Trim(strTest))
returns True .
So,
IsNull(Trim(" ")) in VB6 = ?? in VB.net
Thank you.
There is no IsNull
function in VB.Net. Instead it has other things like String.IsNullOrEmpty
function and String.Empty
property etc. for finding out whether a string is empty or not.
IsNull
in VB6/VBA means whether an expression contains no valid data. You are getting False
in vb6 because you have initialized strTest
. It holds an empty string. You might also want to see THIS
VB6
IsNull(Trim(strTest))
In VB.Net, IsNullOrEmpty
Indicates whether the specified string is Nothing
or an Empty
string.
VB.NET
If String.IsNullOrEmpty(strTest.Trim) Then DoWhatever
If strTest.Trim = String.Empty Then DoWhatever
If strTest.Trim = "" Then DoWhatever '<~~ Same in VB6 as well
If String.IsNullOrWhiteSpace(strTest) Then DoWhatever '<~~ VB2010 onwards only
All these will return True
in VB.Net because the string IS
EMPTY. You might want to see THIS
If your string value is all spaces then either use strTest.Trim()
before using the first 3 options, or use the 4th option directly which checks whether it is nothing, or empty string or all spaces only.