List<T>.Remove Method
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Removes the first occurrence of a specific object from the List<T>.
Namespace: System.Collections.Generic
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
Public Function Remove ( _
item As T _
) As Boolean
public bool Remove(
T item
)
Parameters
Return Value
Type: System.Boolean
true if item is successfully removed; otherwise, false. This method also returns false if item was not found in the List<T>.
Implements
Remarks
This method determines equality using the default equality comparer EqualityComparer<T>.Default for T, the type of values in the list.
This method performs a linear search; therefore, this method is an O(n) operation, where n is Count.
Examples
The following code example demonstrates Remove method. Several properties and methods of the List<T> generic class are used to add, insert, and search the list. After these operations, the list contains a duplicate. The Remove method is used to remove the first instance of the duplicate item, and the contents are displayed. The Remove method always removes the first instance it encounters.
Imports System.Collections.Generic
Public Class Example
Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
Dim dinosaurs As New List(Of String)
outputBlock.Text &= String.Format(vbLf & "Capacity: {0}", dinosaurs.Capacity) & vbCrLf
dinosaurs.Add("Tyrannosaurus")
dinosaurs.Add("Amargasaurus")
dinosaurs.Add("Mamenchisaurus")
dinosaurs.Add("Deinonychus")
dinosaurs.Add("Compsognathus")
outputBlock.Text &= vbCrLf
For Each dinosaur As String In dinosaurs
outputBlock.Text &= dinosaur & vbCrLf
Next
outputBlock.Text &= String.Format(vbLf & "Capacity: {0}", dinosaurs.Capacity) & vbCrLf
outputBlock.Text &= String.Format("Count: {0}", dinosaurs.Count) & vbCrLf
outputBlock.Text &= vbLf & String.Format("Contains(""Deinonychus"": {0}", _
dinosaurs.Contains("Deinonychus")) & vbCrLf
outputBlock.Text &= String.Format(vbLf & "Insert(2, ""Compsognathus"")") & vbCrLf
dinosaurs.Insert(2, "Compsognathus")
outputBlock.Text &= vbCrLf
For Each dinosaur As String In dinosaurs
outputBlock.Text &= dinosaur & vbCrLf
Next
outputBlock.Text &= String.Format(vbLf & "dinosaurs(3): {0}", dinosaurs(3)) & vbCrLf
outputBlock.Text &= vbLf & "Remove(""Compsognathus"")" & vbCrLf
dinosaurs.Remove("Compsognathus")
outputBlock.Text &= vbCrLf
For Each dinosaur As String In dinosaurs
outputBlock.Text &= dinosaur & vbCrLf
Next
dinosaurs.TrimExcess()
outputBlock.Text &= vbLf & "TrimExcess()" & vbCrLf
outputBlock.Text &= String.Format("Capacity: {0}", dinosaurs.Capacity) & vbCrLf
outputBlock.Text &= String.Format("Count: {0}", dinosaurs.Count) & vbCrLf
dinosaurs.Clear()
outputBlock.Text &= vbLf & "Clear()" & vbCrLf
outputBlock.Text &= String.Format("Capacity: {0}", dinosaurs.Capacity) & vbCrLf
outputBlock.Text &= String.Format("Count: {0}", dinosaurs.Count) & vbCrLf
End Sub
End Class
' This code example produces the following output:
'
'Capacity: 0
'
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Deinonychus
'Compsognathus
'
'Capacity: 8
'Count: 5
'
'Contains("Deinonychus"): True
'
'Insert(2, "Compsognathus")
'
'Tyrannosaurus
'Amargasaurus
'Compsognathus
'Mamenchisaurus
'Deinonychus
'Compsognathus
'
'dinosaurs(3): Mamenchisaurus
'
'Remove("Compsognathus")
'
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Deinonychus
'Compsognathus
'
'TrimExcess()
'Capacity: 5
'Count: 5
'
'Clear()
'Capacity: 5
'Count: 0
using System;
using System.Collections.Generic;
public class Example
{
public static void Demo(System.Windows.Controls.TextBlock outputBlock)
{
List<string> dinosaurs = new List<string>();
outputBlock.Text += String.Format("\nCapacity: {0}", dinosaurs.Capacity) + "\n";
dinosaurs.Add("Tyrannosaurus");
dinosaurs.Add("Amargasaurus");
dinosaurs.Add("Mamenchisaurus");
dinosaurs.Add("Deinonychus");
dinosaurs.Add("Compsognathus");
outputBlock.Text += "\n";
foreach (string dinosaur in dinosaurs)
{
outputBlock.Text += dinosaur + "\n";
}
outputBlock.Text += String.Format("\nCapacity: {0}", dinosaurs.Capacity) + "\n";
outputBlock.Text += String.Format("Count: {0}", dinosaurs.Count) + "\n";
outputBlock.Text += String.Format("\nContains(\"Deinonychus\"): {0}",
dinosaurs.Contains("Deinonychus")) + "\n";
outputBlock.Text += String.Format("\nInsert(2, \"Compsognathus\")") + "\n";
dinosaurs.Insert(2, "Compsognathus");
outputBlock.Text += "\n";
foreach (string dinosaur in dinosaurs)
{
outputBlock.Text += dinosaur + "\n";
}
outputBlock.Text += String.Format("\ndinosaurs[3]: {0}", dinosaurs[3]) + "\n";
outputBlock.Text += "\nRemove(\"Compsognathus\")" + "\n";
dinosaurs.Remove("Compsognathus");
outputBlock.Text += "\n";
foreach (string dinosaur in dinosaurs)
{
outputBlock.Text += dinosaur + "\n";
}
dinosaurs.TrimExcess();
outputBlock.Text += "\nTrimExcess()" + "\n";
outputBlock.Text += String.Format("Capacity: {0}", dinosaurs.Capacity) + "\n";
outputBlock.Text += String.Format("Count: {0}", dinosaurs.Count) + "\n";
dinosaurs.Clear();
outputBlock.Text += "\nClear()" + "\n";
outputBlock.Text += String.Format("Capacity: {0}", dinosaurs.Capacity) + "\n";
outputBlock.Text += String.Format("Count: {0}", dinosaurs.Count) + "\n";
}
}
/* This code example produces the following output:
Capacity: 0
Tyrannosaurus
Amargasaurus
Mamenchisaurus
Deinonychus
Compsognathus
Capacity: 8
Count: 5
Contains("Deinonychus"): True
Insert(2, "Compsognathus")
Tyrannosaurus
Amargasaurus
Compsognathus
Mamenchisaurus
Deinonychus
Compsognathus
dinosaurs[3]: Mamenchisaurus
Remove("Compsognathus")
Tyrannosaurus
Amargasaurus
Mamenchisaurus
Deinonychus
Compsognathus
TrimExcess()
Capacity: 5
Count: 5
Clear()
Capacity: 5
Count: 0
*/
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