ReadOnlyCollection<T>.IndexOf(T) Method

Definition

Searches for the specified object and returns the zero-based index of the first occurrence within the entire ReadOnlyCollection<T>.

public int IndexOf (T value);

Parameters

value
T

The object to locate in the List<T>. The value can be null for reference types.

Returns

The zero-based index of the first occurrence of item within the entire ReadOnlyCollection<T>, if found; otherwise, -1.

Implements

Remarks

The ReadOnlyCollection<T> is searched forward starting at the first element and ending at the last element.

This method determines equality using the default comparer EqualityComparer<T>.Default.

This method performs a linear search; therefore, this method is an O(n) operation, where n is Count.

Applies to

Product Versions
.NET Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.0, 2.1
UWP 10.0

See also