Class ListExtensions

Namespace

Cuemon.Extensions.Collections.Generic

Assembly

Cuemon.Extensions.Collections.Generic.dll

Extension methods for the IList<T> interface.

public static class ListExtensions

Inheritance

object

ListExtensions

Examples

ListExtensions provides extension methods for List<T> for safe navigation and manipulation including predicate-based removal, bounds checking, adjacent-element access, and conditional addition. This example creates a list of fruit names ["Apple", "Banana", "Cherry", "Date"], calls Remove with a predicate to delete "Banana", checks whether index 5 exists with HasIndex, and retrieves adjacent elements using Next(0) and Previous(2) without throwing on out-of-bounds access. TryAdd conditionally adds "Cherry" (duplicate, returns false) and "Elderberry" (new, returns true). Console output confirms the removal, bounds-check results, neighbor values, and the success of each conditional addition.

using System;
using System.Collections.Generic;
using Cuemon.Extensions.Collections.Generic;

namespace DocExamples
{
    public static class ListExtensionsExample
    {
        public static void Main()
        {
            var fruits = new List<string> { "Apple", "Banana", "Cherry", "Date" };

            // Remove the first element matching a condition
            bool removed = fruits.Remove(f => f == "Banana");
            Console.WriteLine($"Removed 'Banana': {removed}");
            Console.WriteLine($"Fruits after removal: {string.Join(", ", fruits)}");

            // Check if an index exists in the list
            bool hasIndex = fruits.HasIndex(5);
            Console.WriteLine($"Has index 5: {hasIndex}");
            Console.WriteLine($"Has index 1: {fruits.HasIndex(1)}");

            // Get the next element relative to an index
            string next = fruits.Next(0);
            Console.WriteLine($"Element after index 0: {next}");

            // Get the previous element relative to an index
            string prev = fruits.Previous(2);
            Console.WriteLine($"Element before index 2: {prev}");

            // Returns default when out of bounds
            string beyond = fruits.Next(10);
            Console.WriteLine($"Element after index 10: {(beyond == null ? "null (default)" : beyond)}");

            // Try to add an element (only if not already present)
            bool added = fruits.TryAdd("Cherry");
            Console.WriteLine($"Added 'Cherry' (duplicate): {added}");

            bool addedNew = fruits.TryAdd("Elderberry");
            Console.WriteLine($"Added 'Elderberry' (new): {addedNew}");
            Console.WriteLine($"Fruits: {string.Join(", ", fruits)}");

}}
}

Methods

HasIndex<T>(IList<T>, int)

Determines whether the list of the IList<T> is within the range of the index.

public static bool HasIndex<T>(this IList<T> list, int index)

Parameters

list IList<T>

The IList<T> to extend.

index int

The index to find.

Returns

bool

true if the specified index is within the range of the list; otherwise, false.

Type Parameters

T

The type of elements in the IList<T>.

Exceptions

ArgumentNullException

list is null.

Next<T>(IList<T>, int)

Returns the next element of list relative to index, or the last element of list if index is equal or greater than Count.

public static T Next<T>(this IList<T> list, int index)

Parameters

list IList<T>

The IList<T> to extend.

index int

The index of which to advance to the next element from.

Returns

T

default(TSource) if index is equal or greater than Count; otherwise the next element of list relative to index.

Type Parameters

T

The type of elements in the IList<T>.

Exceptions

ArgumentNullException

list is null.

ArgumentOutOfRangeException

index is less than 0.

Previous<T>(IList<T>, int)

Returns the previous element of list relative to index, or the first or last element of list if index is equal, greater or lower than Count.

public static T Previous<T>(this IList<T> list, int index)

Parameters

list IList<T>

The IList<T> to extend.

index int

The index of which to advance to the previous element from.

Returns

T

default(TSource) if index is equal, greater or lower than Count; otherwise the previous element of list relative to index.

Type Parameters

T

The type of elements in the IList<T>.

Exceptions

ArgumentNullException

list is null.

ArgumentOutOfRangeException

index is less than 0.

Remove<T>(IList<T>, Func<T, bool>)

Removes the first occurrence of a specific object from the list.

public static bool Remove<T>(this IList<T> list, Func<T, bool> predicate)

Parameters

list IList<T>

The IList<T> to extend.

predicate Func<T, bool>

The function delegate that defines the conditions of the element to remove.

Returns

bool

true if item was successfully removed from the list, false otherwise.

Type Parameters

T

The type of elements in the IList<T>.

TryAdd<T>(IList<T>, T)

Attempts to add the specified item to the list.

public static bool TryAdd<T>(this IList<T> list, T item)

Parameters

list IList<T>

The IList<T> to extend.

item T

The item to add.

Returns

bool

true if the item was added to the list successfully, false otherwise.

Type Parameters

T

Remarks

This method will add the specified item to the list if it is not already present.