EmptyControlCollection クラスとは何？わかりやすく解説 Weblio辞書

.NET Framework クラスライブラリリファレンス

索引トップ用語の索引ランキング

EmptyControlCollection クラス

常に空の ControlCollection コレクションの標準サポートを提供します。

名前空間: System.Web.UI
アセンブリ: System.Web (system.web.dll 内)
構文

Visual Basic (宣言)

Public Class EmptyControlCollection
    Inherits ControlCollection

Visual Basic (使用法)

Dim instance As EmptyControlCollection

public class EmptyControlCollection : ControlCollection

C++

public ref class EmptyControlCollection : public
 ControlCollection

public class EmptyControlCollection extends
 ControlCollection

JScript

public class EmptyControlCollection extends
 ControlCollection

解説

このクラスは、子コントロールを許可しないカスタムコントロールを定義する場合に使用されます。

使用例

Visual Basic

' 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