List<T>.GetRange Method
Microsoft Silverlight will reach end of support after October 2021. Learn more.
Creates a shallow copy of a range of elements in the source List<T>.
Namespace: System.Collections.Generic
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
Public Function GetRange ( _
index As Integer, _
count As Integer _
) As List(Of T)
public List<T> GetRange(
int index,
int count
)
Parameters
- index
Type: System.Int32
The zero-based List<T> index at which the range starts.
- count
Type: System.Int32
The number of elements in the range.
Return Value
Type: System.Collections.Generic.List<T>
A shallow copy of a range of elements in the source List<T>.
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>. |
Remarks
A shallow copy of a collection of reference types, or a subset of that collection, contains only the references to the elements of the collection. The objects themselves are not copied. The references in the new list point to the same objects as the references in the original list.
A shallow copy of a collection of value types, or a subset of that collection, contains the elements of the collection. However, if the elements of the collection contain references to other objects, those objects are not copied. The references in the elements of the new collection point to the same objects as the references in the elements of the original collection.
In contrast, a deep copy of a collection copies the elements and everything directly or indirectly referenced by the elements.
This method is an O(n) operation, where n is count.
Examples
The following code example demonstrates the GetRange method and other methods of the List<T> class that act on ranges. At the end of the code example, the GetRange method is used to get three items from the list, beginning with index location 2. The ToArray method is called on the resulting List<T>, creating an array of three elements. The elements of the array are displayed.
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.
See Also