Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

external/referencesource/mscorlib/system/dbnull.cs

@@ -0,0 +1,123 @@
+// ==++==
+// 
+//   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);
+        }
+    }
+}
+