// ==++==
// 
//   
//    Copyright (c) 2006 Microsoft Corporation.  All rights reserved.
//   
//    The use and distribution terms for this software are contained in the file
//    named license.txt, which can be found in the root of this distribution.
//    By using this software in any fashion, you are agreeing to be bound by the
//    terms of this license.
//   
//    You must not remove this notice, or any other, from this software.
//   
// 
// ==--==
////////////////////////////////////////////////////////////////////////////////
// Void
//	This class represents a Missing Variant
////////////////////////////////////////////////////////////////////////////////
namespace System {
    
	using System;
	using System.Runtime.Remoting;
	using System.Runtime.Serialization;
[System.Runtime.InteropServices.ComVisible(true)]
    [Serializable()] public sealed class DBNull : ISerializable, IConvertible {
    
        //Package private constructor
        private DBNull(){
        }

        private DBNull(SerializationInfo info, StreamingContext context) {
            throw new NotSupportedException(Environment.GetResourceString("NotSupported_DBNullSerial"));
        }
    	
    	public static readonly DBNull Value = new DBNull();
    
        public void GetObjectData(SerializationInfo info, StreamingContext context) {
            UnitySerializationHolder.GetUnitySerializationInfo(info, UnitySerializationHolder.NullUnity, null, null);
        }
    
        public override String ToString() {
            return String.Empty;
        }

        public String ToString(IFormatProvider provider) {
            return String.Empty;
        }

        public TypeCode GetTypeCode() {
            return TypeCode.DBNull;
        }

        /// <internalonly/>
        bool IConvertible.ToBoolean(IFormatProvider provider) {
            throw new InvalidCastException(Environment.GetResourceString("InvalidCast_FromDBNull"));
        }

        /// <internalonly/>
        char IConvertible.ToChar(IFormatProvider provider) {
            throw new InvalidCastException(Environment.GetResourceString("InvalidCast_FromDBNull"));
        }

        /// <internalonly/>
        sbyte IConvertible.ToSByte(IFormatProvider provider) {
            throw new InvalidCastException(Environment.GetResourceString("InvalidCast_FromDBNull"));
        }

        /// <internalonly/>
        byte IConvertible.ToByte(IFormatProvider provider) {
            throw new InvalidCastException(Environment.GetResourceString("InvalidCast_FromDBNull"));
        }

        /// <internalonly/>
        short IConvertible.ToInt16(IFormatProvider provider) {
            throw new InvalidCastException(Environment.GetResourceString("InvalidCast_FromDBNull"));
        }

        /// <internalonly/>
        ushort IConvertible.ToUInt16(IFormatProvider provider) {
            throw new InvalidCastException(Environment.GetResourceString("InvalidCast_FromDBNull"));
        }

        /// <internalonly/>
        int IConvertible.ToInt32(IFormatProvider provider) {
            throw new InvalidCastException(Environment.GetResourceString("InvalidCast_FromDBNull"));
        }

        /// <internalonly/>
        uint IConvertible.ToUInt32(IFormatProvider provider) {
            throw new InvalidCastException(Environment.GetResourceString("InvalidCast_FromDBNull"));
        }

        /// <internalonly/>
        long IConvertible.ToInt64(IFormatProvider provider) {
            throw new InvalidCastException(Environment.GetResourceString("InvalidCast_FromDBNull"));
        }

        /// <internalonly/>
        ulong IConvertible.ToUInt64(IFormatProvider provider) {
            throw new InvalidCastException(Environment.GetResourceString("InvalidCast_FromDBNull"));
        }

        /// <internalonly/>
        float IConvertible.ToSingle(IFormatProvider provider) {
            throw new InvalidCastException(Environment.GetResourceString("InvalidCast_FromDBNull"));
        }

        /// <internalonly/>
        double IConvertible.ToDouble(IFormatProvider provider) {
            throw new InvalidCastException(Environment.GetResourceString("InvalidCast_FromDBNull"));
        }

        /// <internalonly/>
        decimal IConvertible.ToDecimal(IFormatProvider provider) {
            throw new InvalidCastException(Environment.GetResourceString("InvalidCast_FromDBNull"));
        }

        /// <internalonly/>
        DateTime IConvertible.ToDateTime(IFormatProvider provider) {
            throw new InvalidCastException(Environment.GetResourceString("InvalidCast_FromDBNull"));
        }

        /// <internalonly/>
        Object IConvertible.ToType(Type type, IFormatProvider provider) {
            return Convert.DefaultToType((IConvertible)this, type, provider);
        }
    }
}