Export (0) Print
Expand All

SortedList.ContainsKey Method

Determines whether a SortedList object contains a specific key.

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

'Declaration
Public Overridable Function ContainsKey ( _
	key As Object _
) As Boolean

Parameters

key
Type: System.Object

The key to locate in the SortedList object.

Return Value

Type: System.Boolean
true if the SortedList object contains an element with the specified key; otherwise, false.

ExceptionCondition
ArgumentNullException

key is Nothing.

InvalidOperationException

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.

This method behaves exactly as the Contains method.

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 whether a SortedList object contains a specific element.

Imports System
Imports System.Collections
Imports Microsoft.VisualBasic

Public Class SamplesSortedList    

    Public Shared Sub Main()

        ' Creates and initializes a new SortedList. 
        Dim mySL As New SortedList()
        mySL.Add(2, "two")
        mySL.Add(4, "four")
        mySL.Add(1, "one")
        mySL.Add(3, "three")
        mySL.Add(0, "zero")

        ' Displays the values of the SortedList.
        Console.WriteLine("The SortedList contains the following values:")
        PrintIndexAndKeysAndValues(mySL)

        ' Searches for a specific key. 
        Dim myKey As Integer = 2
        Dim msg As String 
        If mySL.ContainsKey(myKey) Then
            msg = "in the SortedList" 
        Else
            msg = "NOT in the SortedList" 
        End If
        Console.WriteLine("The key ""{0}"" is {1}.", myKey, msg)
        myKey = 6
        If mySL.ContainsKey(myKey) Then
            msg = "in the SortedList" 
        Else
            msg = "NOT in the SortedList" 
        End If
        Console.WriteLine("The key ""{0}"" is {1}.", myKey, msg)        
        ' Searches for a specific value. 
        Dim myValue As String = "three" 
        If mySL.ContainsValue(myValue) Then
            msg = "in the SortedList" 
        Else
            msg = "NOT in the SortedList" 
        End If
        Console.WriteLine("The value ""{0}"" is {1}.", myValue, msg)
        myValue = "nine" 
        If mySL.ContainsValue(myValue) Then
            msg = "in the SortedList" 
        Else
            msg = "NOT in the SortedList" 
        End If
        Console.WriteLine("The value ""{0}"" is {1}.", myValue, msg)
    End Sub    


    Public Shared Sub PrintIndexAndKeysAndValues(myList As SortedList)
        Console.WriteLine(ControlChars.Tab & "-INDEX-" & ControlChars.Tab & _
           "-KEY-" & ControlChars.Tab & "-VALUE-")
        Dim i As Integer 
        For i = 0 To myList.Count - 1
            Console.WriteLine(ControlChars.Tab & "[{0}]:" & ControlChars.Tab & _
               "{1}" & ControlChars.Tab & "{2}", i, myList.GetKey(i), _
               myList.GetByIndex(i))
        Next i
        Console.WriteLine()
    End Sub 
End Class 

' This code produces the following output. 
'  
' The SortedList contains the following values: 
'     -INDEX-    -KEY-    -VALUE- 
'     [0]:    0    zero 
'     [1]:    1    one 
'     [2]:    2    two 
'     [3]:    3    three 
'     [4]:    4    four 
'  
' The key "2" is in the SortedList. 
' The key "6" is NOT in the SortedList. 
' The value "three" is in the SortedList. 
' The value "nine" is NOT in the SortedList. 

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0
Show:
© 2015 Microsoft