Problem with retrieving UNSRootB object

In Designer > Test script with 'Use transaction' disable:

Public Function TSB_UNSRootB_Get(ByVal Ident_UNSRoot As String) As IEntity

    If String.IsNullOrEmpty(Ident_UNSRoot) Then
		Throw New ArgumentNullException("Ident_UNSRoot")
	End If

	Dim f As ISqlFormatter = Connection.SqlFormatter
	Dim UID_UNSRootB As String = Ident_UNSRoot
	Dim UNSRootB As IEntity = Nothing
	
	If Not StringIsUID(Ident_UNSRoot) Then
   	    UID_UNSRootB = Connection.GetSingleProperty("UNSRootB", "UID_UNSRootB", f.Comparison("Ident_UNSRoot", Ident_UNSRoot, ValType.String, CompareOperator.Equal))
	End If
	
	If Session.Source.TryGet( Query.From("UNSRootB") _
		                           .Where(f.Comparison("UID_UNSRootB", UID_UNSRootB, ValType.String, CompareOperator.Equal)) _
						           .SelectNonLobs, UNSRootB )
		Return UNSRootB
    Else
		Throw New Exception(#LD("Could not determine target system object")#)
    End If

End Function

Public Function StringIsUID(ByVal UID As String) As Boolean
		
	If String.IsNullOrEmpty(UID) Then
		Return False
	End If
		
	Dim regex = New RegularExpressions.Regex("^(\{){0,1}[0-9a-fA-F]{8}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{12}(\}){0,1}$", RegularExpressions.RegexOptions.Compiled)
	Return regex.IsMatch(UID)
		
End Function

As a parameter You can use Ident_UNSRoot or UID_UNSRootB.

When Ident_UNSRoot is used the propert object is returned.

When UID_UNSRootB is used then I got exception.

Your script works for me in either case, using an Ident_UNSRoot or an UID_UNSRootB.

The only suggestion I have is to replace the f.Comparison method with an f.UidComparison method. It might be a rare case, but the generated where-clauses are different.

Your comparison method generates a where-clause like

UID_UNSRootB = N'<UID_UNSRootB>'

while UidComparison generates

UID_UNSRootB = '<UID_UNSRootB>'

In version 7 and above, all UIDs are Non-Unicode so the second where clause is the correct one.

Bonus:

.Where(f.UidComparison("UID_UNSRootB", UID_UNSRootB) ) _

is shorter as well :-)