Represents a value type that can be assigned null. More...

Public Member Functions
	Nullable (T value)
	Initializes a new instance of the T:System.Nullable`1 structure to the specified value. More...

T	GetValueOrDefault ()
	Retrieves the value of the current T:System.Nullable`1 object, or the object's default value. More...

T	GetValueOrDefault (T defaultValue)
	Retrieves the value of the current T:System.Nullable`1 object, or the specified default value. More...

override bool	Equals (object other)
	Indicates whether the current T:System.Nullable`1 object is equal to a specified object. More...

override int	GetHashCode ()
	Retrieves the hash code of the object returned by the P:System.Nullable`1.Value property. More...

override string	ToString ()
	Returns the text representation of the value of the current T:System.Nullable`1 object. More...

Static Public Member Functions
static implicit	operator T? (T value)
	Creates a new T:System.Nullable`1 object initialized to a specified value. More...

static	operator T (T? value)
	Defines an explicit conversion of a T:System.Nullable`1 instance to its underlying value. More...

static int	Compare< T > (T? n1, T? n2)
	Compares the relative values of two T:System.Nullable`1 objects. More...

static bool	Equals< T > (T? n1, T? n2)
	Indicates whether two specified T:System.Nullable`1 objects are equal. More...

static Type	GetUnderlyingType (Type nullableType)
	Returns the underlying type argument of the specified nullable type. More...

Public Attributes
internal T	value

Properties
bool	HasValue `[get]`
	Gets a value indicating whether the current T:System.Nullable`1 object has a valid value of its underlying type. More...

T	Value `[get]`
	Gets the value of the current T:System.Nullable`1 object if it has been assigned a valid underlying value. More...

Detailed Description

Represents a value type that can be assigned null.

Supports a value type that can be assigned null. This class cannot be inherited.

Template Parameters

T	The underlying value type of the T:System.Nullable`1 generic type.

Type Constraints

T

:

struct

Definition at line 12 of file Nullable.cs.

Constructor & Destructor Documentation

◆ Nullable()

System.Nullable< T >.Nullable ( T value )

Initializes a new instance of the T:System.Nullable`1 structure to the specified value.

Parameters

value A value type.

Definition at line 53 of file Nullable.cs.

Member Function Documentation

◆ Compare< T >()

static int System.Nullable< T >.Compare< T >	(	T?	n1,
		T?	n2
	)

static

Compares the relative values of two T:System.Nullable`1 objects.

Parameters

n1	A T:System.Nullable`1 object.
n2	A T:System.Nullable`1 object.

Template Parameters

T	The underlying value type of the n1 and n2 parameters.

Returns: An integer that indicates the relative values of the n1 and n2 parameters.Return ValueDescriptionLess than zeroThe P:System.Nullable`1.HasValue property for n1 is false, and the P:System.Nullable`1.HasValue property for n2 is true.-or-The P:System.Nullable`1.HasValue properties for n1 and n2 are true, and the value of the P:System.Nullable`1.Value property for n1 is less than the value of the P:System.Nullable`1.Value property for n2 .ZeroThe P:System.Nullable`1.HasValue properties for n1 and n2 are false.-or-The P:System.Nullable`1.HasValue properties for n1 and n2 are true, and the value of the P:System.Nullable`1.Value property for n1 is equal to the value of the P:System.Nullable`1.Value property for n2 .Greater than zeroThe P:System.Nullable`1.HasValue property for n1 is true, and the P:System.Nullable`1.HasValue property for n2 is false.-or-The P:System.Nullable`1.HasValue properties for n1 and n2 are true, and the value of the P:System.Nullable`1.Value property for n1 is greater than the value of the P:System.Nullable`1.Value property for n2 .

Type Constraints

T

:

struct

Definition at line 160 of file Nullable.cs.

◆ Equals()

override bool System.Nullable< T >.Equals ( object other )

Indicates whether the current T:System.Nullable`1 object is equal to a specified object.

Parameters

other An object.

Returns: true if the other parameter is equal to the current T:System.Nullable`1 object; otherwise, false. This table describes how equality is defined for the compared values: Return ValueDescription true The P:System.Nullable`1.HasValue property is false, and the other parameter is null. That is, two null values are equal by definition.-or-The P:System.Nullable`1.HasValue property is true, and the value returned by the P:System.Nullable`1.Value property is equal to the other parameter. false The P:System.Nullable`1.HasValue property for the current T:System.Nullable`1 structure is true, and the other parameter is null.-or-The P:System.Nullable`1.HasValue property for the current T:System.Nullable`1 structure is false, and the other parameter is not null.-or-The P:System.Nullable`1.HasValue property for the current T:System.Nullable`1 structure is true, and the value returned by the P:System.Nullable`1.Value property is not equal to the other parameter.

Definition at line 91 of file Nullable.cs.

◆ Equals< T >()

static bool System.Nullable< T >.Equals< T >	(	T?	n1,
		T?	n2
	)

static

Indicates whether two specified T:System.Nullable`1 objects are equal.

Parameters

n1	A T:System.Nullable`1 object.
n2	A T:System.Nullable`1 object.

Template Parameters

T	The underlying value type of the n1 and n2 parameters.

Returns: true if the n1 parameter is equal to the n2 parameter; otherwise, false. The return value depends on the P:System.Nullable`1.HasValue and P:System.Nullable`1.Value properties of the two parameters that are compared.Return ValueDescription true The P:System.Nullable`1.HasValue properties for n1 and n2 are false. -or-The P:System.Nullable`1.HasValue properties for n1 and n2 are true, and the P:System.Nullable`1.Value properties of the parameters are equal. false The P:System.Nullable`1.HasValue property is true for one parameter and false for the other parameter.-or-The P:System.Nullable`1.HasValue properties for n1 and n2 are true, and the P:System.Nullable`1.Value properties of the parameters are unequal.

Type Constraints

T

:

struct

Definition at line 189 of file Nullable.cs.

◆ GetHashCode()

override int System.Nullable< T >.GetHashCode ( )

Retrieves the hash code of the object returned by the P:System.Nullable`1.Value property.

Returns: The hash code of the object returned by the P:System.Nullable`1.Value property if the P:System.Nullable`1.HasValue property is true, or zero if the P:System.Nullable`1.HasValue property is false.

Definition at line 107 of file Nullable.cs.

◆ GetUnderlyingType()

static Type System.Nullable< T >.GetUnderlyingType ( Type nullableType )

static

Returns the underlying type argument of the specified nullable type.

Parameters

nullableType A T:System.Type object that describes a closed generic nullable type.

Returns: The type argument of the nullableType parameter, if the nullableType parameter is a closed generic nullable type; otherwise, null.

Exceptions

T:System.ArgumentNullException nullableType is null.

Definition at line 212 of file Nullable.cs.

◆ GetValueOrDefault() [1/2]

T System.Nullable< T >.GetValueOrDefault ( )

Retrieves the value of the current T:System.Nullable`1 object, or the object's default value.

Returns: The value of the P:System.Nullable`1.Value property if the P:System.Nullable`1.HasValue property is true; otherwise, the default value of the current T:System.Nullable`1 object. The type of the default value is the type argument of the current T:System.Nullable`1 object, and the value of the default value consists solely of binary zeroes.

Definition at line 63 of file Nullable.cs.

◆ GetValueOrDefault() [2/2]

T System.Nullable< T >.GetValueOrDefault ( T defaultValue )

Retrieves the value of the current T:System.Nullable`1 object, or the specified default value.

Parameters

defaultValue A value to return if the P:System.Nullable`1.HasValue property is false.

Returns: The value of the P:System.Nullable`1.Value property if the P:System.Nullable`1.HasValue property is true; otherwise, the defaultValue parameter.

Definition at line 73 of file Nullable.cs.

◆ operator T()

static System.Nullable< T >.operator T ( T? value )

explicitstatic

Defines an explicit conversion of a T:System.Nullable`1 instance to its underlying value.

Parameters

value A nullable value.

Returns: The value of the P:System.Nullable`1.Value property for the value parameter.

Definition at line 143 of file Nullable.cs.

◆ operator T?()

static implicit System.Nullable< T >.operator T? ( T value )

static

Creates a new T:System.Nullable`1 object initialized to a specified value.

Parameters

value A value type.

Returns: A T:System.Nullable`1 object whose P:System.Nullable`1.Value property is initialized with the value parameter.

Definition at line 133 of file Nullable.cs.

◆ ToString()

override string System.Nullable< T >.ToString ( )

Returns the text representation of the value of the current T:System.Nullable`1 object.

Returns: The text representation of the value of the current T:System.Nullable`1 object if the P:System.Nullable`1.HasValue property is true, or an empty string ("") if the P:System.Nullable`1.HasValue property is false.

Definition at line 119 of file Nullable.cs.

Property Documentation

◆ HasValue

bool System.Nullable< T >.HasValue

get

Gets a value indicating whether the current T:System.Nullable`1 object has a valid value of its underlying type.

Returns: true if the current T:System.Nullable`1 object has a value; false if the current T:System.Nullable`1 object has no value.

Definition at line 23 of file Nullable.cs.

◆ Value

T System.Nullable< T >.Value

get

Gets the value of the current T:System.Nullable`1 object if it has been assigned a valid underlying value.

Returns: The value of the current T:System.Nullable`1 object if the P:System.Nullable`1.HasValue property is true. An exception is thrown if the P:System.Nullable`1.HasValue property is false.

Exceptions

T:System.InvalidOperationException The P:System.Nullable`1.HasValue property is false.

Definition at line 37 of file Nullable.cs.

The documentation for this class was generated from the following file:

D:/All cs/System/Nullable.cs

Public Member Functions

Static Public Member Functions

Public Attributes

Properties

Detailed Description

Constructor & Destructor Documentation

◆ Nullable()

Member Function Documentation

◆ Compare< T >()

◆ Equals()

◆ Equals< T >()

◆ GetHashCode()

◆ GetUnderlyingType()

◆ GetValueOrDefault() [1/2]

◆ GetValueOrDefault() [2/2]

◆ operator T()

◆ operator T?()

◆ ToString()

Property Documentation

◆ HasValue

◆ Value