Info You will get a compile-time error if you try to use a wrongly-typed parameter.
Tip ContainsKey and TryGetValue test the internal data structure (an array) in the SortedList instance.
And This can obtain the value associated with the key if it is found in the data structure. It can boost performance on lookups.
using System;
using System.Collections.Generic;
// Create SortedList with 3 keys and values.
var sorted = new SortedList<string, int>();
sorted.Add("zebra", 3);
sorted.Add("cat", 1);
sorted.Add("dog", 2);
// Use ContainsKey.
bool contains1 = sorted.ContainsKey("?");
Console.WriteLine("contains ? = " + contains1);
// Use TryGetValue.
int value;
if (sorted.TryGetValue("zebra", out value))
{
Console.WriteLine("zebra = " + value);
}
// Use item indexer.
Console.WriteLine("cat = " + sorted["cat"]);
// Loop over SortedList data.
foreach (var pair in sorted)
{
Console.WriteLine(pair);
}
// Get index of key and then index of value.
int index1 = sorted.IndexOfKey("cat");
Console.WriteLine("index of cat = " + index1);
int index2 = sorted.IndexOfValue(3);
Console.WriteLine("index of 3 (value) = " + index2);
// Display Count.
Console.WriteLine("count = " + sorted.Count);contains ? = False
zebra = 3
cat = 1
[cat, 1]
[dog, 2]
[zebra, 3]
index of cat = 0
index of 3 (value) = 2
count = 3
Internals. Here we look inside a disassembled version of SortedList. This shows us exactly what the class does when you try to access a key.
Info You can see the IndexOfKey method is invoked each time. The internal array is accessed at that index.
Strings. On a SortedList with string keys, you can improve performance. Specify StringComparer.Ordinal as the comparison method. Pass this in as an argument to the constructor.
TrimExcess. This multiplies the number of keys in the data structure by 90%. It sees if that number is still larger than the capacity. It may adjust the Capacity property.
Keys, Values. These properties can only be read from. They allocate the KeyList data structure and the ValueList data structure before returning the elements.
Note These allocations will only copy the element references. They won't copy all the strings if you use that type as the key or value.
Summary. SortedList will store an internally sorted data structure which it then queries with a BinarySearch method. It does not provide optimal lookup performance.
Dot Net Perls is a collection of tested code examples. Pages are continually updated to stay current, with code correctness a top priority.
Sam Allen is passionate about computer languages. In the past, his work has been recommended by Apple and Microsoft and he has studied computers at a selective university in the United States.
This page was last updated on Apr 4, 2023 (simplify).
