SortedList<TKey,TValue>.TryGetValue(TKey, TValue) Method
Definition
Gets the value associated with the specified key.
public:
virtual bool TryGetValue(TKey key, [Runtime::InteropServices::Out] TValue % value);
public bool TryGetValue (TKey key, out TValue value);
abstract member TryGetValue : 'Key * 'Value -> bool
override this.TryGetValue : 'Key * 'Value -> bool
Public Function TryGetValue (key As TKey, ByRef value As TValue) As Boolean
Parameters
- key
- TKey
The key whose value to get.
- value
- TValue
When this method returns, the value associated with the specified key, if the key is found; otherwise, the default value for the type of the value
parameter. This parameter is passed uninitialized.
Returns
true
if the SortedList<TKey,TValue> contains an element with the specified key; otherwise, false
.
Implements
Exceptions
key
is null
.
Examples
The example shows how to use the TryGetValue method as a more efficient way to retrieve values in a program that frequently tries keys that are not in the sorted list. For contrast, the example also shows how the Item[] property (the indexer in C#) throws exceptions when attempting to retrieve nonexistent keys.
This code example is part of a larger example provided for the SortedList<TKey,TValue> class.
// 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.
String^ value = "";
if (openWith->TryGetValue("tif", value))
{
Console::WriteLine("For key = \"tif\", value = {0}.", value);
}
else
{
Console::WriteLine("Key = \"tif\" is not found.");
}
// 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.
string value = "";
if (openWith.TryGetValue("tif", out value))
{
Console.WriteLine("For key = \"tif\", value = {0}.", value);
}
else
{
Console.WriteLine("Key = \"tif\" is not found.");
}
' 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
// The indexer throws an exception if the requested key is
// not in the list.
try
{
Console::WriteLine("For key = \"tif\", value = {0}.",
openWith["tif"]);
}
catch (KeyNotFoundException^)
{
Console::WriteLine("Key = \"tif\" is not found.");
}
// The indexer throws an exception if the requested key is
// not in the list.
try
{
Console.WriteLine("For key = \"tif\", value = {0}.",
openWith["tif"]);
}
catch (KeyNotFoundException)
{
Console.WriteLine("Key = \"tif\" is not found.");
}
' The default Item property throws an exception if the requested
' key is not in the list.
Try
Console.WriteLine("For key = ""tif"", value = {0}.", _
openWith("tif"))
Catch
Console.WriteLine("Key = ""tif"" is not found.")
End Try
Remarks
This method combines the functionality of the ContainsKey method and the Item[] property.
If the key is not found, then the value
parameter gets the appropriate default value for the value type TValue
; for example, zero (0) for integer types, false
for Boolean types, and null
for reference types.
This method performs a binary search; therefore, this method is an O(log n
) operation, where n
is Count.