StringCollection.Contains Method (String)


Determines whether the specified string is in the StringCollection.

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

Public Function Contains (
	value As String
) As Boolean


Type: System.String

The string to locate in the StringCollection. The value can be null.

Return Value

Type: System.Boolean

true if value is found in the StringCollection; otherwise, false.

The Contains method can confirm the existence of a string before performing further operations.

This method determines equality by calling Object.Equals. String comparisons are case-sensitive.

This method performs a linear search; therefore, this method is an O(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 searches the StringCollection for an element.

Imports System
Imports System.Collections
Imports System.Collections.Specialized

Public Class SamplesStringCollection   

   Public Shared Sub Main()

      ' Creates and initializes a new StringCollection.
      Dim myCol As New StringCollection()
      Dim myArr() As [String] = {"RED", "orange", "yellow", "RED", "green", "blue", "RED", "indigo", "violet", "RED"}

      Console.WriteLine("Initial contents of the StringCollection:")

      ' Checks whether the collection contains "orange" and, if so, displays its index.
      If myCol.Contains("orange") Then
         Console.WriteLine("The collection contains ""orange"" at index {0}.", myCol.IndexOf("orange"))
         Console.WriteLine("The collection does not contain ""orange"".")
      End If 

   End Sub 'Main

   Public Shared Sub PrintValues(myCol As IEnumerable)
      Dim obj As [Object]
      For Each obj In  myCol
         Console.WriteLine("   {0}", obj)
      Next obj
   End Sub 'PrintValues

End Class 'SamplesStringCollection 

'This code produces the following output.
'Initial contents of the StringCollection:
'   RED
'   orange
'   yellow
'   RED
'   green
'   blue
'   RED
'   indigo
'   violet
'   RED
'The collection contains "orange" at index 1.

Universal Windows Platform
Available since 10
.NET Framework
Available since 1.1
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