EmptyControlCollection-Klasse
Bietet Standardunterstützung für eine ControlCollection-Auflistung, die immer leer ist.
Namespace: System.Web.UI
Assembly: System.Web (in system.web.dll)
Syntax
'Declaration
Public Class EmptyControlCollection
Inherits ControlCollection
'Usage
Dim instance As EmptyControlCollection
public class EmptyControlCollection : ControlCollection
public ref class EmptyControlCollection : public ControlCollection
public class EmptyControlCollection extends ControlCollection
public class EmptyControlCollection extends ControlCollection
Hinweise
Diese Klasse wird verwendet, wenn Sie ein benutzerdefiniertes Steuerelement definieren möchten, für das keine untergeordneten Steuerelemente zulässig sind.
Beispiel
' File name: emptyControlCollection.vb.
Imports System
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Collections
Namespace CustomControls
Public Class MyVB_EmptyControl
Inherits Control
<System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.Demand, Name:="FullTrust")> _
Protected Overrides Function CreateControlCollection() As ControlCollection
' Function Name: CreateControlCollection.
' Denies the creation of any child control by creating an empty collection.
' Generates an exception if an attempt to create a child control is made.
Return New EmptyControlCollection(Me)
End Function
<System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.Demand, Name:="FullTrust")> _
Protected Overrides Sub CreateChildControls()
' Sub Name: CreateChildControls.
' Populates the child control collection (Controls).
' Note: This function will cause an exception because the control does not allow
' child controls.
Dim text As LiteralControl
text = New LiteralControl("<h5>Composite Controls</h5>")
Controls.Add(text)
End Sub
End Class
End Namespace
/* File name: emptyControlCollection.cs. */
using System;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Collections;
namespace CustomControls
{
// Defines a simple custom control.
public class MyCS_EmptyControl : Control
{
[System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name="FullTrust")]
protected override ControlCollection CreateControlCollection()
/*
* Function Name: CreateControlCollection.
* Denies the creation of any child control by creating an empty collection.
* Generates an exception if an attempt to create a child control is made.
*/
{
return new EmptyControlCollection(this);
}
[System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name="FullTrust")]
protected override void CreateChildControls()
/*
* Function Name: CreateChildControls.
* Populates the child control collection (Controls).
* Note: This function will cause an exception because the control does not allow
* child controls.
*/
{
// Create a literal control to contain the header and add it to the collection.
LiteralControl text;
text = new LiteralControl("<h5>Composite Controls</h5>");
Controls.Add(text);
}
}
}
/* File name: emptyControlCollection.jsl. */
import System.*;
import System.Web.*;
import System.Web.UI.*;
import System.Web.UI.WebControls.*;
import System.Collections.*;
// Defines a simple custom control.
public class MyJSL_EmptyControl extends Control
{
// /** @attribute System.Security.Permissions.PermissionSet(
// System.Security.Permissions.SecurityAction.Demand, Name = "FullTrust")
// */
protected ControlCollection CreateControlCollection()
/*
Function Name: CreateControlCollection.
Denies the creation of any child control by creating an empty
collection.
Generates an exception if an attempt to create a child control is
made.
*/
{
return new EmptyControlCollection(this);
} //CreateControlCollection
/** @attribute System.Security.Permissions.PermissionSet(
System.Security.Permissions.SecurityAction.Demand, Name = "FullTrust")
*/
protected void CreateChildControls()
/*
Function Name: CreateChildControls.
Populates the child control collection (Controls).
Note: This function will cause an exception because the control
does not allow child controls.
*/
{
// Create a literal control to contain the header and add it to the
// collection.
LiteralControl text;
text = new LiteralControl("<h5>Composite Controls</h5>");
get_Controls().Add(text);
} //CreateChildControls
} //MyJSL_EmptyControl
Vererbungshierarchie
System.Object
System.Web.UI.ControlCollection
System.Web.UI.EmptyControlCollection
Threadsicherheit
Alle öffentlichen statischen (Shared in Visual Basic) Member dieses Typs sind threadsicher. Bei Instanzmembern ist die Threadsicherheit nicht gewährleistet.
Plattformen
Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.
Versionsinformationen
.NET Framework
Unterstützt in: 2.0, 1.1, 1.0