| Description |
A new Queue is created with the same number of elements, and entries as the current Queue.
When the current queue holds reference (non primitive) data types, the cloned queue element values still refer to the same objects that current queue elements refer to. This is what is referred to as a shallow copy. A deep copy would create new versions of the referred objects.
|
| | Notes | You are obliged to cast the resultant Object to a Queue before assignment to a Queue variable.
|
|
| Microsoft MSDN Links |
System.Collections
System.Collections.Queue
|
|
|
| A simple example |
// Full Unit code.
// -------------------------------------------------------------
// Create a new WinForm application, double click the form to
// create an OnLoad event, and then replace the WinForm unit
// with this text.
unit WinForm;
interface
uses
System.Drawing, System.Collections, System.ComponentModel,
System.Windows.Forms, System.Data;
type
TWinForm = class(System.Windows.Forms.Form)
\{REGION 'Designer Managed Code'\} // Note that REGION and ENREGION should be prefixed by a dollar sign
strict private
///
/// Required designer variable.
///
Components: System.ComponentModel.Container;
///
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
///
procedure InitializeComponent;
procedure TWinForm_Load(sender: System.Object; e: System.EventArgs);
{ENDREGION}
strict protected
///
/// Clean up any resources being used.
///
procedure Dispose(Disposing: Boolean); override;
private
{ Private Declarations }
public
constructor Create;
end;
[assembly: RuntimeRequiredAttribute(TypeOf(TWinForm))]
implementation
\{REGION 'Windows Form Designer generated code'\}
///
/// Required method for Designer support -- do not modify
/// the contents of this method with the code editor.
///
procedure TWinForm.InitializeComponent;
begin
//
// TWinForm
//
Self.AutoScaleBaseSize := System.Drawing.Size.Create(5, 13);
Self.ClientSize := System.Drawing.Size.Create(292, 266);
Self.Name := 'TWinForm';
Self.Text := 'WinForm';
Include(Self.Load, Self.TWinForm_Load);
end;
{ENDREGION}
procedure TWinForm.Dispose(Disposing: Boolean);
begin
if Disposing then
begin
if Components <> nil then
Components.Dispose();
end;
inherited Dispose(Disposing);
end;
constructor TWinForm.Create;
begin
inherited Create;
//
// Required for Windows Form Designer support
//
InitializeComponent;
//
// TODO: Add any constructor code after InitializeComponent call
//
end;
procedure TWinForm.TWinForm_Load(sender: System.Object; e: System.EventArgs);
program Project1;
{$APPTYPE CONSOLE}
uses
System.Collections;
var
Source, Target : System.Collections.Queue;
Enumerator : IEnumerator;
begin
// Create our queues
Source := Queue.Create;
Target := Queue.Create;
// Add entries to the source queue
Source.EnQueue('First');
Source.EnQueue('Second');
Source.Enqueue('Third');
// Display the queue
Console.WriteLine('Source queue :');
Console.WriteLine;
Enumerator := Source.GetEnumerator;
while Enumerator.MoveNext do
Console.WriteLine(Enumerator.Current.ToString);
// Clone the queue!
Target := Queue(Source.Clone);
// Display the target
Console.WriteLine;
Console.WriteLine('Cloned queue :');
Console.WriteLine;
Enumerator := Target.GetEnumerator;
while Enumerator.MoveNext do
Console.WriteLine(Enumerator.Current.ToString);
Console.Readline;
end.
end. | | Hide full unit code | Source queue :
First
Second
Third
Cloned queue :
First
Second
Third
|
| |
|
|
|