DBNull

DBNull CF 1.0, serializable

System (mscorlib.dll) sealed class

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 null keyword in C#. The null 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 sealed class  DBNull  : System.Runtime.Serialization.ISerializable, IConvertible {  // Public Static Fields  public static readonly DBNull  Value  ;  // Public Instance Methods  public void  GetObjectData  (System.Runtime.Serialization.SerializationInfo   info   ,         System.Runtime.Serialization.StreamingContext   context   )  // implements ISerializable  public TypeCode  GetTypeCode  ( );  // implements IConvertible  public override string  ToString  ( );  // overrides object  public string  ToString  (IFormatProvider   provider   );  // implements IConvertible  } 


C# in a Nutshell
C # in a Nutshell, Second Edition
ISBN: 0596005261
EAN: 2147483647
Year: 2005
Pages: 963

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