2007-11-14 Zoltan Varga <vargaz@gmail.com>

[mono.git] / mcs / class / corlib / System / DBNull.cs

diff --git a/mcs/class/corlib/System/DBNull.cs b/mcs/class/corlib/System/DBNull.cs
index 8af6929e57e24a7d548270ad4ece6a9b917916d0..4cb26fed1f7c7a42b2086630f684c5b7211034b0 100644 (file)
--- a/mcs/class/corlib/System/DBNull.cs
+++ b/mcs/class/corlib/System/DBNull.cs
@@ -1,23 +1,60 @@
 //
 // System.DBNull.cs
 //
-// Author: Duncan Mak (duncan@ximian.com)
+// Authors:
+//   Duncan Mak (duncan@ximian.com)
+//   Ben Maurer (bmaurer@users.sourceforge.net)
 //
 // (C) 2002 Ximian, Inc. http://www.ximian.com
+// (C) 2003 Ben Maurer
+//
+
+//
+// Copyright (C) 2004 Novell, Inc (http://www.novell.com)
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+// 
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 //
 
 using System.Runtime.Serialization;
+using System.Runtime.InteropServices;
 
 namespace System
 {
        [Serializable]
+#if NET_2_0
+       [ComVisible (true)]
+#endif
        public sealed class DBNull : ISerializable, IConvertible
        {
                // Fields
                public static readonly DBNull Value = new DBNull ();
 
                // Private constructor
-               private DBNull () {}
+               private DBNull ()
+               {
+               }
+
+               private DBNull (SerializationInfo info, StreamingContext context)
+               {
+                       throw new NotSupportedException ();
+               }
 
                // Methods
                public void GetObjectData (SerializationInfo info, StreamingContext context)
@@ -30,94 +67,81 @@ namespace System
                        return TypeCode.DBNull;
                }
 
-               [MonoTODO]
                bool IConvertible.ToBoolean (IFormatProvider provider)
                {
-                       return false;
+                       throw new InvalidCastException ();
                }                       
 
-               [MonoTODO]
                byte IConvertible.ToByte (IFormatProvider provider)
                {
-                       return Byte.MinValue;
+                       throw new InvalidCastException ();
                }
 
-               [MonoTODO]
                char IConvertible.ToChar (IFormatProvider provider)
                {
-                       return Char.MinValue;
+                       throw new InvalidCastException ();
                }
 
-               [MonoTODO]
                DateTime IConvertible.ToDateTime (IFormatProvider provider)
                {
-                       return DateTime.MinValue;
+                       throw new InvalidCastException ();
                }
 
-               [MonoTODO]
                decimal IConvertible.ToDecimal (IFormatProvider provider)
                {
-                       return Decimal.MinValue;
+                       throw new InvalidCastException ();
                }
                
-               [MonoTODO]
                double IConvertible.ToDouble (IFormatProvider provider)
                {
-                       return Double.MinValue;
+                       throw new InvalidCastException ();
                }
 
-               [MonoTODO]
                short IConvertible.ToInt16 (IFormatProvider provider)
                {
-                       return Int16.MinValue;
+                       throw new InvalidCastException ();
                }
 
-               [MonoTODO]
                int IConvertible.ToInt32 (IFormatProvider provider)
                {
-                       return Int32.MinValue;
+                       throw new InvalidCastException ();
                }
 
-               [MonoTODO]
                long IConvertible.ToInt64 (IFormatProvider provider)
                {
-                       return Int64.MinValue;
+                       throw new InvalidCastException ();
                }
 
-               [MonoTODO]
                sbyte IConvertible.ToSByte (IFormatProvider provider)
                {
-                       return SByte.MinValue;
+                       throw new InvalidCastException ();
                }
 
-               [MonoTODO]
                float IConvertible.ToSingle (IFormatProvider provider)
                {
-                       return Single.MinValue;
+                       throw new InvalidCastException ();
                }
 
-               [MonoTODO]
                object IConvertible.ToType (Type type, IFormatProvider provider)
                {
-                       return null;
+                       if (type == typeof (string))
+                               return String.Empty;
+                       throw new InvalidCastException ();
                }
 
-               [MonoTODO]
                ushort IConvertible.ToUInt16 (IFormatProvider provider)
                {
-                       return UInt16.MinValue;
+                       throw new InvalidCastException ();
                }
 
-               [MonoTODO]
                uint IConvertible.ToUInt32 (IFormatProvider provider)
                {
-                       return UInt32.MinValue;
+                       throw new InvalidCastException ();
                }
 
-               [MonoTODO]
                ulong IConvertible.ToUInt64 (IFormatProvider provider)
                {
-                       return UInt64.MinValue;
+                       throw new InvalidCastException ();
                }
 
                public override string ToString ()