Return False on empty cells when checking if file or directory exists in UDF

Question

Given sample Excel data in the format:

filepath	test
C:\file.txt	=PERSONAL.XLSB!checkExists(A2)
C:\dir\file.txt	TRUE
C:\fake_dir	FALSE
C:\fake_dir\file.txt	FALSE
	TRUE

• A1 and A2 are headers
• The values in A2 and A3 are filepaths that exist
• A4 is a directory that does not exist
• A5 is a file that cannot exist because its directory does not exist
• A6 is blank
• B2 just shows how I'm calling the formula (it's saved in my PERSONAL.XLSB project container thing)

I want to run the following User-Defined Formula, called checkExists; this uses DIR to check the value in a given cell to see if that directory or file exists, and returns a boolean.

Public Function checkExists(path As String) As Boolean

'   Check if string is empty
    If (IsEmpty(path) = False) Then

'       Check if file/dir exists
        If ((Dir(path, vbNormal + vbDirectory)) <> vbNullString = False) Then
'           String is not empty, and file/dir exists; return True
            checkExists = True

        Else
'           File does not exist; return False
            checkExists = False
        
        End If
    
    Else
'       String is empty; return False
        checkExists = False
    
    End If

End Function

I'm struggling with getting it to recognise that a given cell is blank -- such as A6 here. The formula as written returns TRUE here, when I need FALSE.

I realise I'm passing it a String, and there is probably another object type I need to pass it, such as a Range or Variant... but I can't work out how to get those object types to work with my code. I also don't know if using both vbNormal (files) and vbDirectory (directories) is causing an issue. I've looked up calling things like ActiveCell, {Range}.Address, and so on, but I'm stuck.

Any help would be much appreciated. Thank you.

Answer 1

Check If File or Folder Exist Using Dir

Using Len

Public Function checkExists(fPath As String) As Boolean

'   Check if the length of the string is greater than 0
    If Len(fPath) > 0 Then

'       Check if the length of 'Dir' is greater than 0
        If Len(Dir(fPath, vbNormal + vbDirectory)) > 0 Then

'           File/dir exists; return True
            checkExists = True

        Else
'           File does not exist; checkExists is False by default
            'checkExists = False
        
        End If
    
    Else
'       The length of the string is 0; checkExists is False by default
        'checkExists = False
    
    End If

End Function

Short

Using Len

Public Function checkExistsLen(fPath As String) As Boolean
    If Len(fPath) > 0 Then
        If Len(Dir(fPath, vbNormal + vbDirectory)) > 0 Then
            checkExists = True
        End If
    End If
End Function

Using vbNullString or ""

Public Function checkExists(fPath As String) As Boolean
    If fPath <> "" Then
        If Dir(fPath, vbNormal + vbDirectory) <> "" Then
            checkExists = True
        End If
    End If
End Function