SortedList(Of TKey, TValue).ContainsKey Method (TKey)
Determines whether the SortedList(Of TKey, TValue) contains a specific key.
Assembly: System (in System.dll)
Parameters
- key
-
Type:
TKey
The key to locate in the SortedList(Of TKey, TValue).
Return Value
Type: System.Booleantrue if the SortedList(Of TKey, TValue) contains an element with the specified key; otherwise, false.
| Exception | Condition |
|---|---|
| ArgumentNullException | key is null. |
The following code example shows how to use the ContainsKey method to test whether a key exists prior to calling the Add method. It also shows how to use the TryGetValue method to retrieve values, which is an efficient way to retrieve values when a program frequently tries keys that are not in the sorted list. Finally, it shows the least efficient way to test whether keys exist, by using the Item property (the indexer in C#).
This code example is part of a larger example provided for the SortedList(Of TKey, TValue) class.
' ContainsKey can be used to test keys before inserting ' them. If Not openWith.ContainsKey("ht") Then openWith.Add("ht", "hypertrm.exe") Console.WriteLine("Value added for key = ""ht"": {0}", _ openWith("ht")) End If
' When a program often has to try keys that turn out not to ' be in the list, TryGetValue can be a more efficient ' way to retrieve values. Dim value As String = "" If openWith.TryGetValue("tif", value) Then Console.WriteLine("For key = ""tif"", value = {0}.", value) Else Console.WriteLine("Key = ""tif"" is not found.") End If
Available since 10
.NET Framework
Available since 2.0