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// ==++==
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// ==--==
////////////////////////////////////////////////////////////////////////////////
// Void
// This class represents a Missing Variant
////////////////////////////////////////////////////////////////////////////////
namespace System {
using System;
using System.Runtime.Remoting;
using System.Runtime.Serialization;
using System.Security.Permissions;
[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();
[System.Security.SecurityCritical]
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);
}
}
}
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