SortedDictionary<TKey,TValue>.ContainsKey(TKey) SortedDictionary<TKey,TValue>.ContainsKey(TKey) SortedDictionary<TKey,TValue>.ContainsKey(TKey) SortedDictionary<TKey,TValue>.ContainsKey(TKey) Method

Definição

Determina se o SortedDictionary<TKey,TValue> contém um elemento com a chave especificada.Determines whether the SortedDictionary<TKey,TValue> contains an element with the specified key.

public:
 virtual bool ContainsKey(TKey key);
public bool ContainsKey (TKey key);
abstract member ContainsKey : 'Key -> bool
override this.ContainsKey : 'Key -> bool
Public Function ContainsKey (key As TKey) As Boolean

Parâmetros

key
TKey TKey TKey TKey

A chave a ser localizada no SortedDictionary<TKey,TValue>.The key to locate in the SortedDictionary<TKey,TValue>.

Retornos

true se o SortedDictionary<TKey,TValue> contiver um elemento com a chave especificada; caso contrário, false.true if the SortedDictionary<TKey,TValue> contains an element with the specified key; otherwise, false.

Implementações

Exceções

Exemplos

O exemplo de código a seguir mostra como usar ContainsKey o método para testar se uma chave existe antes de chamar Add o método.The following code example shows how to use the ContainsKey method to test whether a key exists prior to calling the Add method. Ele também mostra como usar o TryGetValue método para recuperar valores, que é uma maneira eficiente de recuperar valores quando um programa tenta com frequência chaves que não estão no dicionário.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 dictionary. Por fim, ele mostra a maneira menos eficiente de testar se as chaves existem, usando Item[TKey] a propriedade (o indexador C#em).Finally, it shows the least efficient way to test whether keys exist, by using the Item[TKey] property (the indexer in C#).

Este exemplo de código faz parte de um exemplo maior fornecido para SortedDictionary<TKey,TValue> a classe.This code example is part of a larger example provided for the SortedDictionary<TKey,TValue> class.

// ContainsKey can be used to test keys before inserting 
// them.
if (!openWith.ContainsKey("ht"))
{
    openWith.Add("ht", "hypertrm.exe");
    Console.WriteLine("Value added for key = \"ht\": {0}", 
        openWith["ht"]);
}
' 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 dictionary, 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 dictionary, 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 dictionary.
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 dictionary.
Try
    Console.WriteLine("For key = ""tif"", value = {0}.", _
        openWith("tif"))
Catch 
    Console.WriteLine("Key = ""tif"" is not found.")
End Try

Comentários

Esse método é uma operação O ( nlog).This method is an O(log n) operation.

Aplica-se a

Veja também