StringCollection Class
Assembly: System (in system.dll)
'Declaration <SerializableAttribute> _ Public Class StringCollection Implements IList, ICollection, IEnumerable 'Usage Dim instance As StringCollection
/** @attribute SerializableAttribute() */ public class StringCollection implements IList, ICollection, IEnumerable
SerializableAttribute public class StringCollection implements IList, ICollection, IEnumerable
Not applicable.
The following code example demonstrates several of the properties and methods of StringCollection.
Imports System Imports System.Collections Imports System.Collections.Specialized Public Class SamplesStringCollection Public Shared Sub Main() ' Create and initializes a new StringCollection. Dim myCol As New StringCollection() ' Add a range of elements from an array to the end of the StringCollection. Dim myArr() As String = {"RED", "orange", "yellow", "RED", "green", "blue", "RED", "indigo", "violet", "RED"} myCol.AddRange(myArr) ' Display the contents of the collection using foreach. This is the preferred method. Console.WriteLine("Displays the elements using foreach:") PrintValues1(myCol) ' Display the contents of the collection using the enumerator. Console.WriteLine("Displays the elements using the IEnumerator:") PrintValues2(myCol) ' Display the contents of the collection using the Count and Item properties. Console.WriteLine("Displays the elements using the Count and Item properties:") PrintValues3(myCol) ' Add one element to the end of the StringCollection and insert another at index 3. myCol.Add("* white") myCol.Insert(3, "* gray") Console.WriteLine("After adding ""* white"" to the end and inserting ""* gray"" at index 3:") PrintValues1(myCol) ' Remove one element from the StringCollection. myCol.Remove("yellow") Console.WriteLine("After removing ""yellow"":") PrintValues1(myCol) ' Remove all occurrences of a value from the StringCollection. Dim i As Integer = myCol.IndexOf("RED") While i > - 1 myCol.RemoveAt(i) i = myCol.IndexOf("RED") End While ' Verify that all occurrences of "RED" are gone. If myCol.Contains("RED") Then Console.WriteLine("*** The collection still contains ""RED"".") End If Console.WriteLine("After removing all occurrences of ""RED"":") PrintValues1(myCol) ' Copy the collection to a new array starting at index 0. Dim myArr2(myCol.Count) As String myCol.CopyTo(myArr2, 0) Console.WriteLine("The new array contains:") For i = 0 To myArr2.Length - 1 Console.WriteLine(" [{0}] {1}", i, myArr2(i)) Next i Console.WriteLine() ' Clears the entire collection. myCol.Clear() Console.WriteLine("After clearing the collection:") PrintValues1(myCol) End Sub 'Main ' Uses the foreach statement which hides the complexity of the enumerator. ' NOTE: The foreach statement is the preferred way of enumerating the contents of a collection. Public Shared Sub PrintValues1(myCol As StringCollection) Dim obj As [Object] For Each obj In myCol Console.WriteLine(" {0}", obj) Next obj Console.WriteLine() End Sub 'PrintValues1 ' Uses the enumerator. ' NOTE: The foreach statement is the preferred way of enumerating the contents of a collection. Public Shared Sub PrintValues2(myCol As StringCollection) Dim myEnumerator As StringEnumerator = myCol.GetEnumerator() While myEnumerator.MoveNext() Console.WriteLine(" {0}", myEnumerator.Current) End While Console.WriteLine() End Sub 'PrintValues2 ' Uses the Count and Item properties. Public Shared Sub PrintValues3(myCol As StringCollection) Dim i As Integer For i = 0 To myCol.Count - 1 Console.WriteLine(" {0}", myCol(i)) Next i Console.WriteLine() End Sub 'PrintValues3 End Class 'SamplesStringCollection 'This code produces the following output. ' 'Displays the elements using foreach: ' RED ' orange ' yellow ' RED ' green ' blue ' RED ' indigo ' violet ' RED ' 'Displays the elements using the IEnumerator: ' RED ' orange ' yellow ' RED ' green ' blue ' RED ' indigo ' violet ' RED ' 'Displays the elements using the Count and Item properties: ' RED ' orange ' yellow ' RED ' green ' blue ' RED ' indigo ' violet ' RED ' 'After adding "* white" to the end and inserting "* gray" at index 3: ' RED ' orange ' yellow ' * gray ' RED ' green ' blue ' RED ' indigo ' violet ' RED ' * white ' 'After removing "yellow": ' RED ' orange ' * gray ' RED ' green ' blue ' RED ' indigo ' violet ' RED ' * white ' 'After removing all occurrences of "RED": ' orange ' * gray ' green ' blue ' indigo ' violet ' * white ' 'The new array contains: ' [0] orange ' [1] * gray ' [2] green ' [3] blue ' [4] indigo ' [5] violet ' [6] * white ' 'After clearing the collection: '
import System.* ;
import System.Collections.* ;
import System.Collections.Specialized.* ;
public class SamplesStringCollection
{
public static void main(String[] args)
{
// Create and initializes a new StringCollection.
StringCollection myCol = new StringCollection();
// Add a range of elements from an array to the end of the
// StringCollection.
String myArr[] = new String[] { "RED", "orange", "yellow", "RED",
"green", "blue", "RED", "indigo", "violet", "RED" };
myCol.AddRange(myArr);
// Display the contents of the collection using foreach. This is the
// preferred method.
Console.WriteLine("Displays the elements using for:");
PrintValues1(myCol);
// Display the contents of the collection using the enumerator.
Console.WriteLine("Displays the elements using the IEnumerator:");
PrintValues2(myCol);
// Display the contents of the collection using the Count and Item
// properties.
Console.WriteLine("Displays the elements using the Count and Item"
+ " properties:");
PrintValues3(myCol);
// Add one element to the end of the StringCollection and insert
// another at index 3.
myCol.Add("* white");
myCol.Insert(3, "* gray");
Console.WriteLine("After adding \"* white\" to the end and inserting"
+ " \"* gray\" at index 3:");
PrintValues1(myCol);
// Remove one element from the StringCollection.
myCol.Remove("yellow");
Console.WriteLine("After removing \"yellow\":");
PrintValues1(myCol);
// Remove all occurrences of a value from the StringCollection.
int i = myCol.IndexOf("RED");
while (i > -1) {
myCol.RemoveAt(i);
i = myCol.IndexOf("RED");
}
// Verify that all occurrences of "RED" are gone.
if (myCol.Contains("RED")) {
Console.WriteLine("*** The collection still contains \"RED\".");
}
Console.WriteLine("After removing all occurrences of \"RED\":");
PrintValues1(myCol);
// Copy the collection to a new array starting at index 0.
String myArr2[] = new String[myCol.get_Count()];
myCol.CopyTo(myArr2, 0);
Console.WriteLine("The new array contains:");
for (i = 0; i < myArr2.length; i++) {
Console.WriteLine(" [{0}] {1}", System.Convert.ToString(i),
myArr2.get_Item(i));
}
Console.WriteLine();
// Clears the entire collection.
myCol.Clear();
Console.WriteLine("After clearing the collection:");
PrintValues1(myCol);
} //main
public static void PrintValues1(StringCollection myCol)
{
Object obj = new Object();
for (int iCtr = 0; iCtr < myCol.get_Count(); iCtr++) {
obj = myCol.get_Item(iCtr);
Console.WriteLine(" {0}", obj);
}
Console.WriteLine();
} //PrintValues1
// Uses the enumerator.
public static void PrintValues2(StringCollection myCol)
{
StringEnumerator myEnumerator = myCol.GetEnumerator();
while (myEnumerator.MoveNext()) {
Console.WriteLine(" {0}", myEnumerator.get_Current());
}
Console.WriteLine();
} //PrintValues2
// Uses the Count and Item properties.
public static void PrintValues3(StringCollection myCol)
{
for (int i = 0; i < myCol.get_Count(); i++) {
Console.WriteLine(" {0}", myCol.get_Item(i));
}
Console.WriteLine();
} //PrintValues3
} //SamplesStringCollection
/*
This code produces the following output.
Displays the elements using for:
RED
orange
yellow
RED
green
blue
RED
indigo
violet
RED
Displays the elements using the IEnumerator:
RED
orange
yellow
RED
green
blue
RED
indigo
violet
RED
Displays the elements using the Count and Item properties:
RED
orange
yellow
RED
green
blue
RED
indigo
violet
RED
After adding "* white" to the end and inserting "* gray" at index 3:
RED
orange
yellow
* gray
RED
green
blue
RED
indigo
violet
RED
* white
After removing "yellow":
RED
orange
* gray
RED
green
blue
RED
indigo
violet
RED
* white
After removing all occurrences of "RED":
orange
* gray
green
blue
indigo
violet
* white
The new array contains:
[0] orange
[1] * gray
[2] green
[3] blue
[4] indigo
[5] violet
[6] * white
After clearing the collection:
*/
System.Collections.Specialized.StringCollection
System.Configuration.CommaDelimitedStringCollection
Public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
This implementation does not provide a synchronized (thread safe) wrapper for a StringCollection, but derived classes can create their own synchronized versions of the StringCollection using the SyncRoot property.
Enumerating through a collection is intrinsically not a thread safe procedure. Even when a collection is synchronized, other threads can still modify the collection, which causes the enumerator to throw an exception. To guarantee thread safety during enumeration, you can either lock the collection during the entire enumeration or catch the exceptions resulting from changes made by other threads.
Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.