Code:
/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / clr / src / BCL / System / Nullable.cs / 1305376 / Nullable.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== using System; namespace System { using System.Globalization; using System.Reflection; using System.Collections.Generic; using System.Runtime; using System.Runtime.CompilerServices; using System.Security; using System.Diagnostics.Contracts; // Warning, don't put System.Runtime.Serialization.On*Serializ*Attribute // on this class without first fixing ObjectClone::InvokeVtsCallbacks // Also, because we have special type system support that says a a boxed Nullable// can be used where a boxed is use, Nullable can not implement any intefaces // at all (since T may not). Do NOT add any interfaces to Nullable! // [TypeDependencyAttribute("System.Collections.Generic.NullableComparer`1")] [TypeDependencyAttribute("System.Collections.Generic.NullableEqualityComparer`1")] [Serializable] public struct Nullable where T : struct { private bool hasValue; internal T value; #if !FEATURE_CORECLR [TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")] #endif public Nullable(T value) { this.value = value; this.hasValue = true; } public bool HasValue { get { return hasValue; } } public T Value { #if !FEATURE_CORECLR [TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")] #endif get { if (!HasValue) { ThrowHelper.ThrowInvalidOperationException(ExceptionResource.InvalidOperation_NoValue); } return value; } } #if !FEATURE_CORECLR [TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")] #endif public T GetValueOrDefault() { return value; } public T GetValueOrDefault(T defaultValue) { return HasValue ? value : defaultValue; } public override bool Equals(object other) { if (!HasValue) return other == null; if (other == null) return false; return value.Equals(other); } public override int GetHashCode() { return HasValue ? value.GetHashCode() : 0; } public override string ToString() { return HasValue ? value.ToString() : ""; } public static implicit operator Nullable (T value) { return new Nullable (value); } public static explicit operator T(Nullable value) { return value.Value; } // The following already obsoleted methods were removed: // public int CompareTo(object other) // public int CompareTo(Nullable other) // public bool Equals(Nullable other) // public static Nullable FromObject(object value) // public object ToObject() // public string ToString(string format) // public string ToString(IFormatProvider provider) // public string ToString(string format, IFormatProvider provider) // The following newly obsoleted methods were removed: // string IFormattable.ToString(string format, IFormatProvider provider) // int IComparable.CompareTo(object other) // int IComparable >.CompareTo(Nullable other) // bool IEquatable >.Equals(Nullable other) } [System.Runtime.InteropServices.ComVisible(true)] public static class Nullable { [System.Runtime.InteropServices.ComVisible(true)] public static int Compare (Nullable n1, Nullable n2) where T : struct { if (n1.HasValue) { if (n2.HasValue) return Comparer .Default.Compare(n1.value, n2.value); return 1; } if (n2.HasValue) return -1; return 0; } [System.Runtime.InteropServices.ComVisible(true)] public static bool Equals (Nullable n1, Nullable n2) where T : struct { if (n1.HasValue) { if (n2.HasValue) return EqualityComparer .Default.Equals(n1.value, n2.value); return false; } if (n2.HasValue) return false; return true; } // If the type provided is not a Nullable Type, return null. // Otherwise, returns the underlying type of the Nullable type public static Type GetUnderlyingType(Type nullableType) { if((object)nullableType == null) { throw new ArgumentNullException("nullableType"); } Contract.EndContractBlock(); Type result = null; if( nullableType.IsGenericType && !nullableType.IsGenericTypeDefinition) { // instantiated generic type only Type genericType = nullableType.GetGenericTypeDefinition(); if( Object.ReferenceEquals(genericType, typeof(Nullable<>))) { result = nullableType.GetGenericArguments()[0]; } } return result; } // The following already obsoleted methods were removed: // public static bool HasValue (Nullable value) // public static T GetValueOrDefault (Nullable value) // public static T GetValueOrDefault (Nullable value, T valueWhenNull) // The following newly obsoleted methods were removed: // public static Nullable FromObject (object value) // public static object ToObject (Nullable value) // public static object Wrap(object value, Type type) // public static object Unwrap(object value) } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- Binding.cs
- IndexOutOfRangeException.cs
- TextChangedEventArgs.cs
- DataGridViewControlCollection.cs
- TextServicesContext.cs
- SerializableAttribute.cs
- ParallelRangeManager.cs
- OraclePermission.cs
- DocumentCollection.cs
- XmlCharacterData.cs
- Object.cs
- TextSelection.cs
- DummyDataSource.cs
- CallId.cs
- AsyncSerializedWorker.cs
- PasswordRecovery.cs
- SelectionProcessor.cs
- WindowsRebar.cs
- ResourceAssociationSet.cs
- HtmlInputSubmit.cs
- SendMailErrorEventArgs.cs
- QilNode.cs
- StylusCollection.cs
- MouseButton.cs
- WaitHandle.cs
- GridViewUpdatedEventArgs.cs
- AssemblyNameProxy.cs
- BuilderPropertyEntry.cs
- ChtmlTextBoxAdapter.cs
- RightsManagementEncryptedStream.cs
- MachineKeyValidationConverter.cs
- RowParagraph.cs
- Rotation3DAnimation.cs
- WpfKnownType.cs
- QilLiteral.cs
- CodeGenerator.cs
- StructureChangedEventArgs.cs
- LingerOption.cs
- ListenerUnsafeNativeMethods.cs
- _CookieModule.cs
- GridSplitterAutomationPeer.cs
- XmlJsonWriter.cs
- LogFlushAsyncResult.cs
- Stacktrace.cs
- dataSvcMapFileLoader.cs
- CultureData.cs
- Rotation3D.cs
- ListView.cs
- TextEditorSpelling.cs
- RowsCopiedEventArgs.cs
- FormViewPageEventArgs.cs
- DbMetaDataCollectionNames.cs
- ToolStripOverflow.cs
- ScriptReferenceBase.cs
- ErrorItem.cs
- PropertyDescriptorCollection.cs
- CompletionProxy.cs
- MessageBodyDescription.cs
- WebWorkflowRole.cs
- SimpleBitVector32.cs
- NotifyCollectionChangedEventArgs.cs
- Control.cs
- SoapServerProtocol.cs
- Hash.cs
- CompilerTypeWithParams.cs
- WeakReferenceEnumerator.cs
- SafeMILHandle.cs
- sqlinternaltransaction.cs
- UserValidatedEventArgs.cs
- DataObjectAttribute.cs
- DeviceSpecificDesigner.cs
- DriveNotFoundException.cs
- CompositeCollection.cs
- RoleServiceManager.cs
- SerializationStore.cs
- PolygonHotSpot.cs
- RemotingSurrogateSelector.cs
- RoutedEvent.cs
- WSSecurityOneDotZeroReceiveSecurityHeader.cs
- IdentityManager.cs
- EntityTransaction.cs
- SqlBooleanizer.cs
- ZipIOBlockManager.cs
- PlatformCulture.cs
- WebPartEditorCancelVerb.cs
- TrackBarRenderer.cs
- XmlSerializerFactory.cs
- PartialCachingAttribute.cs
- HttpEncoderUtility.cs
- EventlogProvider.cs
- TextRangeAdaptor.cs
- autovalidator.cs
- ResourceSet.cs
- Currency.cs
- MarkupExtensionReturnTypeAttribute.cs
- CallContext.cs
- CodePropertyReferenceExpression.cs
- DataServiceQueryOfT.cs
- UserPreferenceChangedEventArgs.cs
- ReceiveParametersContent.cs