Article
11/18/2011

List<T>.RemoveRange Method

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Removes a range of elements from the List<T>.

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

Syntax

'Declaration
Public Sub RemoveRange ( _
    index As Integer, _
    count As Integer _
)

public void RemoveRange(
    int index,
    int count
)

Parameters

index
Type: System.Int32
The zero-based starting index of the range of elements to remove.

count
Type: System.Int32
The number of elements to remove.

Exceptions

Exception	Condition
ArgumentOutOfRangeException	index is less than 0. -or- count is less than 0.
ArgumentException	index and count do not denote a valid range of elements in the List<T>.

ArgumentOutOfRangeException

index is less than 0.

-or-

count is less than 0.

ArgumentException

index and count do not denote a valid range of elements in the List<T>.

Remarks

The items are removed and all the elements following them in the List<T> have their indexes reduced by count.

This method is an O(n) operation, where n is Count.

Examples

The following code example demonstrates the RemoveRange method and various other methods of the List<T> class that act on ranges. After the list has been created and modified, the RemoveRange method is used to remove two elements from the list, beginning at index location 2.

Imports System.Collections.Generic

Public Class Example

   Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)

      Dim input() As String = {"Brachiosaurus", _
                                "Amargasaurus", _
                                "Mamenchisaurus"}

      Dim dinosaurs As New List(Of String)(input)

      outputBlock.Text += String.Format(vbLf & "Capacity: {0}", dinosaurs.Capacity) & vbCrLf

      outputBlock.Text &= vbCrLf
      For Each dinosaur As String In dinosaurs
         outputBlock.Text &= dinosaur & vbCrLf
      Next

      outputBlock.Text &= vbLf & "AddRange(dinosaurs)" & vbCrLf
      dinosaurs.AddRange(dinosaurs)

      outputBlock.Text &= vbCrLf
      For Each dinosaur As String In dinosaurs
         outputBlock.Text &= dinosaur & vbCrLf
      Next

      outputBlock.Text += String.Format(vbLf & "RemoveRange(2, 2)") & vbCrLf
      dinosaurs.RemoveRange(2, 2)

      outputBlock.Text &= vbCrLf
      For Each dinosaur As String In dinosaurs
         outputBlock.Text &= dinosaur & vbCrLf
      Next

      input = New String() {"Tyrannosaurus", _
                             "Deinonychus", _
                             "Velociraptor"}

      outputBlock.Text += String.Format(vbLf & "InsertRange(3, input)") & vbCrLf
      dinosaurs.InsertRange(3, input)

      outputBlock.Text &= vbCrLf
      For Each dinosaur As String In dinosaurs
         outputBlock.Text &= dinosaur & vbCrLf
      Next

      outputBlock.Text += String.Format(vbLf & "output = dinosaurs.GetRange(2, 3).ToArray") & vbCrLf
      Dim output() As String = dinosaurs.GetRange(2, 3).ToArray()

      outputBlock.Text &= vbCrLf
      For Each dinosaur As String In output
         outputBlock.Text &= dinosaur & vbCrLf
      Next

   End Sub
End Class

' This code example produces the following output:
'
'Capacity: 3
'
'Brachiosaurus
'Amargasaurus
'Mamenchisaurus
'
'AddRange(dinosaurs)
'
'Brachiosaurus
'Amargasaurus
'Mamenchisaurus
'Brachiosaurus
'Amargasaurus
'Mamenchisaurus
'
'RemoveRange(2, 2)
'
'Brachiosaurus
'Amargasaurus
'Amargasaurus
'Mamenchisaurus
'
'InsertRange(3, input)
'
'Brachiosaurus
'Amargasaurus
'Amargasaurus
'Tyrannosaurus
'Deinonychus
'Velociraptor
'Mamenchisaurus
'
'output = dinosaurs.GetRange(2, 3).ToArray
'
'Amargasaurus
'Tyrannosaurus
'Deinonychus

using System;
using System.Collections.Generic;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      string[] input = { "Brachiosaurus", 
                           "Amargasaurus", 
                           "Mamenchisaurus" };

      List<string> dinosaurs = new List<string>(input);

      outputBlock.Text += String.Format("\nCapacity: {0}", dinosaurs.Capacity) + "\n";

      outputBlock.Text += "\n";
      foreach (string dinosaur in dinosaurs)
      {
         outputBlock.Text += dinosaur + "\n";
      }

      outputBlock.Text += "\nAddRange(dinosaurs)" + "\n";
      dinosaurs.AddRange(dinosaurs);

      outputBlock.Text += "\n";
      foreach (string dinosaur in dinosaurs)
      {
         outputBlock.Text += dinosaur + "\n";
      }

      outputBlock.Text += String.Format("\nRemoveRange(2, 2)") + "\n";
      dinosaurs.RemoveRange(2, 2);

      outputBlock.Text += "\n";
      foreach (string dinosaur in dinosaurs)
      {
         outputBlock.Text += dinosaur + "\n";
      }

      input = new string[] { "Tyrannosaurus", 
                               "Deinonychus", 
                               "Velociraptor"};

      outputBlock.Text += String.Format("\nInsertRange(3, input)") + "\n";
      dinosaurs.InsertRange(3, input);

      outputBlock.Text += "\n";
      foreach (string dinosaur in dinosaurs)
      {
         outputBlock.Text += dinosaur + "\n";
      }

      outputBlock.Text += String.Format("\noutput = dinosaurs.GetRange(2, 3).ToArray()") + "\n";
      string[] output = dinosaurs.GetRange(2, 3).ToArray();

      outputBlock.Text += "\n";
      foreach (string dinosaur in output)
      {
         outputBlock.Text += dinosaur + "\n";
      }
   }
}

/* This code example produces the following output:

Capacity: 3

Brachiosaurus
Amargasaurus
Mamenchisaurus

AddRange(dinosaurs)

Brachiosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Amargasaurus
Mamenchisaurus

RemoveRange(2, 2)

Brachiosaurus
Amargasaurus
Amargasaurus
Mamenchisaurus

InsertRange(3, input)

Brachiosaurus
Amargasaurus
Amargasaurus
Tyrannosaurus
Deinonychus
Velociraptor
Mamenchisaurus

output = dinosaurs.GetRange(2, 3).ToArray()

Amargasaurus
Tyrannosaurus
Deinonychus
 */

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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