Struct Optional<T>

Namespace

ReactiveUI.Extensions.Async

Assembly

ReactiveUI.Extensions.dll

Represents an optional value that may or may not be present.

public readonly struct Optional<T> : IEquatable<Optional<T>>

Type Parameters

T

The type of the value that may be contained by the optional.

Implements

IEquatable<Optional<T>>

Extension Methods

OptionalMixins.TryGetValue<T>(Optional<T>, out T?)

ReactiveExtensions.Schedule<T>(T, DateTimeOffset, IScheduler)

ReactiveExtensions.Schedule<T>(T, DateTimeOffset, IScheduler, Action<T>)

ReactiveExtensions.Schedule<T>(T, IScheduler, Func<T, T>)

ReactiveExtensions.Schedule<T>(T, TimeSpan, IScheduler)

ReactiveExtensions.Schedule<T>(T, TimeSpan, IScheduler, Action<T>)

ReactiveExtensions.Schedule<T>(T, TimeSpan, IScheduler, Func<T, T>)

Remarks

Use this struct to indicate the presence or absence of a value without resorting to null references. When an instance has a value, the HasValue property is true and the Value property returns the contained value. If no value is present, HasValue is false and accessing Value throws an exception. This pattern is useful for APIs that need to distinguish between an explicit 'no value' state and a default value.

Constructors

Optional()

Initializes a new instance of the Optional<T> struct.

public Optional()

Remarks

After using this constructor, the HasValue property is set to false, indicating that the Optional<T> instance does not contain a value.

Optional(T)

Initializes a new instance of the Optional<T> struct.

public Optional(T value)

Parameters

value T

The value to be contained in the Optional<T> instance.

Properties

Empty

Gets an empty instance of the Optional<T> type that contains no value.

public static Optional<T> Empty { get; }

Property Value

Optional<T>

Remarks

Use this property to represent the absence of a value in a type-safe manner. The returned instance has no value set and IsPresent is false.

HasValue

Gets a value indicating whether the current instance has a valid value assigned.

public bool HasValue { get; }

Property Value

bool

Value

Gets the value contained in the optional object.

public T? Value { get; }

Property Value

T

Remarks

Accessing this property when the optional object does not have a value will throw an exception. Use the HasValue property to determine whether a value is present before accessing this property.

Methods

Equals(Optional<T>)

public bool Equals(Optional<T> other)

Parameters

other Optional<T>

Returns

bool

Equals(object)

public override bool Equals(object obj)

Parameters

obj object

Returns

bool

GetHashCode()

public override int GetHashCode()

Returns

int

ToString()

public override string ToString()

Returns

string

Operators

operator ==(Optional<T>, Optional<T>)

public static bool operator ==(Optional<T> left, Optional<T> right)

Parameters

left Optional<T>

right Optional<T>

Returns

bool

operator !=(Optional<T>, Optional<T>)

public static bool operator !=(Optional<T> left, Optional<T> right)

Parameters

left Optional<T>

right Optional<T>

Returns

bool