Struct ReadOnlyArray<TValue>

Read-only access to an array or to a slice of an array.

Inherited Members
Namespace: UnityEngine.InputSystem.Utilities
Syntax
public struct ReadOnlyArray<TValue> : IReadOnlyList<TValue>, IReadOnlyCollection<TValue>, IEnumerable<TValue>, IEnumerable
Type Parameters
Name Description
TValue

Type of values stored in the array.
Remarks

The purpose of this struct is to allow exposing internal arrays directly such that no boxing and no going through interfaces is required but at the same time not allowing the internal arrays to be modified.

It differs from ReadOnlySpan<T> in that it can be stored on the heap and differs from ReadOnlyCollection<T> in that it supports slices directly without needing an intermediate object representing the slice.

Note that in most cases, the ReadOnlyArray instance should be treated as a temporary. The actual array referred to by a ReadOnlyArray instance is usually owned and probably mutated by another piece of code. When that code makes changes to the array, the ReadOnlyArray instance will not get updated.

Constructors

ReadOnlyArray(TValue[])

Construct a read-only array covering all of the given array.

Declaration
public ReadOnlyArray(TValue[] array)
Parameters
Type Name Description
TValue[] array

Array to index.

ReadOnlyArray(TValue[], Int32, Int32)

Construct a read-only array that covers only the given slice of array.

Declaration
public ReadOnlyArray(TValue[] array, int index, int length)
Parameters
Type Name Description
TValue[] array

Array to index.
Int32 index

Index at which to start indexing array. The given element becomes index #0 for the read-only array.
Int32 length

Length of the slice to index from array.

Properties

Count

Number of elements in the array.

Declaration
public readonly int Count { get; }
Property Value
Type Description
Int32
Implements

Item[Int32]

Return the element at the given index.

Declaration
public readonly TValue this[int index] { get; }
Parameters
Type Name Description
Int32 index

Index into the array.
Property Value
Type Description
TValue
Implements
Exceptions
Type Condition
IndexOutOfRangeException

index is less than 0 or greater than Count.
InvalidOperationException

Methods

GetEnumerator()

Returns an enumerator that iterates through the read-only array. ReadOnlyArray<TValue>.Enumerator An enumerator for the read-only array.

Declaration
public ReadOnlyArray<TValue>.Enumerator GetEnumerator()
Returns
Type Description
ReadOnlyArray.Enumerator<>

IndexOf(Predicate<TValue>)

Searches for the first element in the array for which the given predicate is true and returns the index of that element.

Declaration
public int IndexOf(Predicate<TValue> predicate)
Parameters
Type Name Description
Predicate<TValue> predicate

The predicate to be evaluated for each element which defines the condition for the search.
Returns
Type Description
Int32

Index of the first element for which predicate is truex or -1 if no such element exists.
Examples
// Searches for the first element in an integer array that is greater or equal to 5.
var haystack = new ReadOnlyArray<int>(new[] { 1, 2, 3, 4, 5, 6, 7 });
var index = haystack.IndexOf((value) => value >= 5); // index == 4
Exceptions
Type Condition
ArgumentNullException

If predicate is null.

ToArray()

Convert to array.

Declaration
public TValue[] ToArray()
Returns
Type Description
TValue[]

A new array containing a copy of the contents of the read-only array.

Operators

Implicit(TValue[] to ReadOnlyArray<TValue>)

Constructs a read-only array containing elements array.

Declaration
public static implicit operator ReadOnlyArray<TValue>(TValue[] array)
Parameters
Type Name Description
TValue[] array

An existing array containing elements to be wrapped as a read-only array.
Returns
Type Description
ReadOnlyArray<TValue>

Explicit Interface Implementations

IEnumerable<TValue>.GetEnumerator()

Declaration
IEnumerator<TValue> IEnumerable<TValue>.GetEnumerator()
Returns
Type Description
IEnumerator<TValue>
Implements

IEnumerable.GetEnumerator()

Declaration
IEnumerator IEnumerable.GetEnumerator()
Returns
Type Description
IEnumerator
Implements