Imports System
Imports System.Collections
Imports System.Collections.Specialized
Public Class SamplesStringDictionary
Public Shared Sub Main()
' Creates and initializes a new StringDictionary.
Dim myCol As New StringDictionary()
myCol.Add("red", "rojo")
myCol.Add("green", "verde")
myCol.Add("blue", "azul")
' Display the contents of the collection using For Each. This is the preferred method.
Console.WriteLine("Displays the elements using For Each:")
PrintKeysAndValues1(myCol)
' Display the contents of the collection using the enumerator.
Console.WriteLine("Displays the elements using the IEnumerator:")
PrintKeysAndValues2(myCol)
' Display the contents of the collection using the Keys, Values, Count, and Item properties.
Console.WriteLine("Displays the elements using the Keys, Values, Count, and Item properties:")
PrintKeysAndValues3(myCol)
' Copies the StringDictionary to an array with DictionaryEntry elements.
Dim myArr(myCol.Count) As DictionaryEntry
myCol.CopyTo(myArr, 0)
' Displays the values in the array.
Console.WriteLine("Displays the elements in the array:")
Console.WriteLine(" KEY VALUE")
Dim i As Integer
For i = 0 To myArr.Length - 1
Console.WriteLine(" {0,-10} {1}", myArr(i).Key, myArr(i).Value)
Next i
Console.WriteLine()
' Searches for a value.
If myCol.ContainsValue("amarillo") Then
Console.WriteLine("The collection contains the value ""amarillo"".")
Else
Console.WriteLine("The collection does not contain the value ""amarillo"".")
End If
Console.WriteLine()
' Searches for a key and deletes it.
If myCol.ContainsKey("green") Then
myCol.Remove("green")
End If
Console.WriteLine("The collection contains the following elements after removing ""green"":")
PrintKeysAndValues1(myCol)
' Clears the entire collection.
myCol.Clear()
Console.WriteLine("The collection contains the following elements after it is cleared:")
PrintKeysAndValues1(myCol)
End Sub 'Main
' Uses the For Each statement which hides the complexity of the enumerator.
' NOTE: The For Each statement is the preferred way of enumerating the contents of a collection.
Public Shared Sub PrintKeysAndValues1(myCol As StringDictionary)
Console.WriteLine(" KEY VALUE")
Dim de As DictionaryEntry
For Each de In myCol
Console.WriteLine(" {0,-25} {1}", de.Key, de.Value)
Next de
Console.WriteLine()
End Sub 'PrintKeysAndValues1
' Uses the enumerator.
' NOTE: The For Each statement is the preferred way of enumerating the contents of a collection.
Public Shared Sub PrintKeysAndValues2(myCol As StringDictionary)
Dim myEnumerator As IEnumerator = myCol.GetEnumerator()
Dim de As DictionaryEntry
Console.WriteLine(" KEY VALUE")
While myEnumerator.MoveNext()
de = CType(myEnumerator.Current, DictionaryEntry)
Console.WriteLine(" {0,-25} {1}", de.Key, de.Value)
End While
Console.WriteLine()
End Sub 'PrintKeysAndValues2
' Uses the Keys, Values, Count, and Item properties.
Public Shared Sub PrintKeysAndValues3(myCol As StringDictionary)
Dim myKeys(myCol.Count) As String
myCol.Keys.CopyTo(myKeys, 0)
Console.WriteLine(" INDEX KEY VALUE")
Dim i As Integer
For i = 0 To myCol.Count - 1
Console.WriteLine(" {0,-5} {1,-25} {2}", i, myKeys(i), myCol(myKeys(i)))
Next i
Console.WriteLine()
End Sub 'PrintKeysAndValues3
End Class 'SamplesStringDictionary
'This code produces the following output.
'
'Displays the elements using For Each:
' KEY VALUE
' red rojo
' blue azul
' green verde
'
'Displays the elements using the IEnumerator:
' KEY VALUE
' red rojo
' blue azul
' green verde
'
'Displays the elements using the Keys, Values, Count, and Item properties:
' INDEX KEY VALUE
' 0 red rojo
' 1 blue azul
' 2 green verde
'
'Displays the elements in the array:
' KEY VALUE
' red rojo
' blue azul
' green verde
'
'
'The collection does not contain the value "amarillo".
'
'The collection contains the following elements after removing "green":
' KEY VALUE
' red rojo
' blue azul
'
'The collection contains the following elements after it is cleared:
' KEY VALUE