VB.NET Core Classes in a Nutshell

Name

DBNull

Synopsis

DBNull indicates the absence of information, typically in a database application in which a field does not contain any data. The types in the System.Data.SqlTypes namespace have built-in support for DBNull.

Note that Value is not the same as the Nothing keyword in VB.NET. The Nothing keyword can be used to release an object by clearing the reference. System.DBNull.Value, on the other hand, is a reference to a special value (a member of the singleton class DBNull) that is used to indicate missing information.

This class has some other uses, namely in COM Interop, in which it represents a VT_EMPTY variant (as opposed to a VT_NULL variant, which is a null reference).

Public NotInheritable Class DBNull : Implements System.Runtime.Serialization.ISerializable, IConvertible
' Public Shared Fields
   Public Shared ReadOnly Value As DBNull  
' Public Instance Methods
   Public Sub GetObjectData(
        ByVal info As System.Runtime.Serialization.SerializationInfo, 
        ByVal context As System.Runtime.Serialization.StreamingContext) 
        Implements ISerializable.GetObjectData 
   Public Function GetTypeCode(
        ) As TypeCode Implements IConvertible.GetTypeCode 
   Overrides Public Function ToString() As String  
   Public Function ToString(
        ByVal provider As IFormatProvider) As String Implements IConvertible.ToString 
End Class