Handling Null Values

Question

User1122355199 posted

Hello everyone and thanks for your help in advance.  I have inherited some code that I now need to debug.  At the heart of the problem is the handling of null values within a class.  Here is a code sample:

Private mstrModifier1 As String

    Public Property Modifier1() As String
        Get
            Return mstrModifier1
        End Get
        Set(ByVal value As String)
            mstrModifier1 = value
        End Set
    End Property

The value is set by parsing a text string:

        If Len(CurrentLineItem.CPTCode) > 10 Then
            'Get the Modifier 1
            CurrentLineItem.Modifier1 = Mid(CurrentLineItem.CPTCode, 10, 2)
        End If

In other words, the current line may not always set to a value.  Since the variable is not initialized to a value when declared, I think the variable may be set to null.   In these cases, when I try to write to a database using:

sqlComm.Parameters.AddWithValue("mod1", CurrentLineItem.Modifier1)

I receive an error Procedure or function 'sproc' expects parameter '@mod1', which was not supplied.  The column is set up accept null values.  So I'm not exactly sure of the best way to fix this problem.  I know I can set the value of the variable of the string to "" at the declaration.  Or I could check to see if the value is set and if not, set it to null or set up the parameter as nullable.  I guess I'm looking at guidance on what the best practice would be.  Any help would be appreciated.