SortedList.IndexOfKey Method (Object)


Returns the zero-based index of the specified key in a SortedList object.

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

abstract IndexOfKey : 
        key:Object -> int
override IndexOfKey : 
        key:Object -> int


Type: System.Object

The key to locate in the SortedList object.

Return Value

Type: System.Int32

The zero-based index of the key parameter, if key is found in the SortedList object; otherwise, -1.

Exception Condition

key is null.


The comparer throws an exception.

The elements of a SortedList object are sorted by the keys either according to a specific IComparer implementation specified when the SortedList is created, or according to the IComparable implementation provided by the keys themselves.

The index sequence is based on the sort sequence. When an element is added, it is inserted into SortedList in the correct sort order, and the indexing adjusts accordingly. When an element is removed, the indexing also adjusts accordingly. Therefore, the index of a specific key/value pair might change as elements are added or removed from the SortedList.

This method uses a binary search algorithm; therefore, this method is an O(log n) operation, where n is Count.

Starting with the .NET Framework 2.0, this method uses the collection’s objects’ Equals and CompareTo methods on item to determine whether item exists. In the earlier versions of the .NET Framework, this determination was made by using the Equals and CompareTo methods of the item parameter on the objects in the collection.

The following code example shows how to determine the index of a key or a value in a SortedList object.

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

Universal Windows Platform
Available since 10
.NET Framework
Available since 1.1
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