KeyedCollection<'TKey, 'TItem>.Remove Method ('TKey)

 

Removes the element with the specified key from the KeyedCollection<'TKey, 'TItem>.

Namespace:   System.Collections.ObjectModel
Assembly:  mscorlib (in mscorlib.dll)

member Remove : 
        key:'TKey -> bool

Parameters

key
Type: TKey

The key of the element to remove.

Return Value

Type: System.Boolean

true if the element is successfully removed; otherwise, false. This method also returns false if key is not found in the KeyedCollection<'TKey, 'TItem>.

Exception Condition
ArgumentNullException

key is null.

The key of the element is also removed from the lookup dictionary.

If the number of elements has exceeded the dictionary creation threshold and the KeyedCollection<'TKey, 'TItem> is using a lookup dictionary, it will continue to use a lookup dictionary even though the number of elements is again under the threshold.

System_CAPS_noteNote

To customize the behavior of this method, override the RemoveItem method.

This method is an O(n) operation, where n is Count.

This code example shows the minimum code necessary to derive a collection class from KeyedCollection<'TKey, 'TItem>: overriding the GetKeyForItem method and providing a public constructor that delegates to a base class constructor. The code example also demonstrates many of the properties and methods inherited from KeyedCollection<'TKey, 'TItem> and Collection<'T> classes.

The example demonstrates Remove method inherited from KeyedCollection<'TKey, 'TItem>, which removes the item with a specified key, and also the Remove and RemoveAt methods inherited from Collection<'T>, which remove by object and by index respectively.

The SimpleOrder class is a very simple requisition list that contains OrderItem objects, each of which represents a line item in the order. The key of OrderItem is immutable, an important consideration for classes that derive from KeyedCollection<'TKey, 'TItem>. For a code example that uses mutable keys, see ChangeItemKey.

No code example is currently available or this language may not be supported.

Universal Windows Platform
Available since 8
.NET Framework
Available since 2.0
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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