ControlBuilderAttribute 類別

參考

定義

命名空間:: System.Web.UI

組件:: System.Web.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

指定 ControlBuilder 類別以便在 ASP.NET 剖析器 (Parser) 內建置自訂控制項。此類別無法獲得繼承。

public ref class ControlBuilderAttribute sealed : Attribute

[System.AttributeUsage(System.AttributeTargets.Class)]
public sealed class ControlBuilderAttribute : Attribute

[<System.AttributeUsage(System.AttributeTargets.Class)>]
type ControlBuilderAttribute = class
    inherit Attribute

Public NotInheritable Class ControlBuilderAttribute
Inherits Attribute

繼承: Object

Attribute
ControlBuilderAttribute

屬性: AttributeUsageAttribute

範例

下列程式代碼範例會建立自定義的選取清單，用來根據 SelectedIndex 運行時間定義的和 Message 值來顯示訊息。下列命令行是用來建置可執行檔。

vbc /r:System.dll /r:System.Web.dll /r:System.Drawing.dll /t:library /out:myWebAppPath/Bin/vb_MyControlBuilderAtt.dll ControlBuilderAtt.vb

csc /t:library /out:myWebAppPath/Bin/cs_MyControlBuilderAtt.dll ControlBuilderAtt.cs


/* File name: controlBuilderAttribute.cs. */

using System;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Collections;

namespace CustomControls

{
  public class MyCS_Item : Control 
  /* Class name: MyCS_Item. 
   * Defines the child control class.
   */
    {

      private String _message;

      public String Message 
      {
        get 
        {
          return _message;
        }
        set 
        {
           _message = value;
        }
     }
    }

    public class CustomParseControlBuilder : ControlBuilder 
    /* Class name: CustomParserControlBuilder.
     * Defines the functions and data to be used in building custom controls. 
     * This class is referenced using the ControlBuilderAttribute class. See class below.
     */
    {
      [System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name="FullTrust")] 
      public override Type GetChildControlType(String tagName, IDictionary attributes) 
      {
        if (String.Compare(tagName, "customitem", true) == 0) 
        {
           return typeof(MyCS_Item);
        }
        return null;
      }
    }

    [ 
       ControlBuilderAttribute(typeof(CustomParseControlBuilder)) 
    ]
    public class MyCS_CustomParse : Control 
    /* Class name: MyCS_CustomParse.
     * Performs custom parsing of a MyCS_CustomParse control type 
     * child control. 
     * If the child control is of the allowed type, it is added to an 
     * array list. This list is accessed, using the container control attribute 
     * SelectedIndex, to obtain the related child control Message attribute to be displayed.
     */
    {

       private ArrayList _items         = new ArrayList();
       private int       _selectedIndex = 0;

       public int SelectedIndex 
       { 
           get 
           {
              return _selectedIndex;
           }
           set 
           {
              _selectedIndex = value;
           }
       }

       [System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name="FullTrust")] 
       protected override void AddParsedSubObject(Object obj) 
       /* Function name: AddParsedSubObject.
        * Updates the array list with the allowed child objects.
        * This function is called during the parsing of the child controls and 
        * after the GetChildControlType function defined in the associated control 
        * builder class.
        */
       {
          if (obj is MyCS_Item) 
         {
              _items.Add(obj);
           }
       }

       [System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name="FullTrust")] 
       protected override void Render(HtmlTextWriter output) 
       /* Function name: Render.
        * Establishes the rules to render the built control. In this case, a message is
        * rendered that is a function of the parent control SelectedIndex attribute and 
        * the related child Message attribute.
        */
       {
          if (SelectedIndex < _items.Count) 
         {
              output.Write("<span style='background-color:aqua; color:red; font:8pt tahoma, verdana;'><b>" +
              ((MyCS_Item) _items[SelectedIndex]).Message + "</b></span>" );
         }
       }
    }    
}


'File name: controlBuilderAttribute.vb.

Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Collections



Namespace CustomControls

Public Class MyVB_Item: Inherits Control
      
      Private _message As String
      
      Public Property Message() As String
         Get
            Return _message
         End Get
         Set
            _message = value
         End Set
      End Property
   End Class
   
   Public Class VB_CustomParseControlBuilder: Inherits ControlBuilder

      <System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.Demand, Name:="FullTrust")>  _
      Public Overrides Function GetChildControlType(TagName As String, attributes As IDictionary) As Type
          If (TagName = "customitem")  Then
            Return GetType(CustomControls.MyVB_Item)
         End If
         Return Nothing
      End Function 'GetChildControlType
   End Class
   
   <ControlBuilderAttribute(GetType(VB_CustomParseControlBuilder))>  Public Class MyVB_CustomParse: Inherits Control
      
      Private _items As New ArrayList
      Private _selectedIndex As Integer = 0
      
      
      Public Property SelectedIndex() As Integer
         Get
            Return _selectedIndex
         End Get
         Set
            _selectedIndex = value
         End Set
      End Property
      
      <System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.Demand, Name:="FullTrust")> _
      Protected Overrides Sub AddParsedSubObject(obj As Object)
         If TypeOf obj Is MyVB_Item Then
            _items.Add(obj)
         End If
      End Sub
      
      <System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.Demand, Name:="FullTrust")> _
      Protected Overrides Sub Render(output As HtmlTextWriter)        
        output.Write(("<span style='background-color:aqua; color:red; font:8pt tahoma, verdana;'><b>" + CType(_items(SelectedIndex), MyVB_Item).Message + "</b></span>"))
      End Sub
   End Class
   
End Namespace 'CustomControls

下列範例使用上述定義的自定義控制項。特別是，它會在運行時間指派 SelectedIndex 和 Message 值，以判斷要轉譯的訊息。請注意，指示詞中顯示的 Register 值會反映上一個命令行。

<%@ Register TagPrefix="custom" Assembly="myControlBuilderAtt" Namespace="CustomControls" %>  
 <h4>Using ControlBuilderAttribute Class<h4>  
 <form runat="server">  
  <custom:MyVB_CustomParse SelectedIndex="3" runat=server>  
  <customitem Message="Visual Basic version. Item One selected"/>  
  <customitem Message="Visual Basic version. Item Two selected"/>  
  <customitem Message="Visual Basic version. Item Three selected"/>  
  <customitem Message="Visual Basic version. Item Four selected"/>  
  </custom:MyVB_CustomParse>  
 </form>

<%@ Register TagPrefix="custom" Assembly="myControlBuilderAtt" Namespace="CustomControls" %>  
 <h4>Using ControlBuilderAttribute Class<h4>  
 <form runat="server">  
  <custom:MyCS_CustomParse SelectedIndex="2" runat=server>  
  <customitem Message="C# version. Item One selected"/>  
  <customitem Message="C# version. Item Two selected"/>  
  <customitem Message="C# version. Item Three selected"/>  
  <customitem Message="C# version. Item Four selected"/>  
  </custom:MyCS_CustomParse>  
 </form>

備註

此屬性會指定要用來建立自定義控制元件的產生器 Type ，如下列程式代碼所示：

[ControlBuilderAttribute(typeof(ControlBuilderType))]

建構函式

ControlBuilderAttribute(Type)

為自訂控制項指定控制項產生器。

欄位

Default

指定新的 ControlBuilderAttribute 物件。根據預設，新的物件會設定為 null。此欄位為唯讀。

屬性

BuilderType	取得與屬性關聯的控制項 Type。這個屬性是唯讀的。
TypeId	在衍生類別中實作時，取得這個 Attribute 的唯一識別碼。 (繼承來源 Attribute)

方法

Equals(Object)	取得值，指出目前的 ControlBuilderAttribute 是否與指定的物件相同。
GetHashCode()	傳回 ControlBuilderAttribute 物件的雜湊程式碼。
GetType()	取得目前執行個體的 Type。 (繼承來源 Object)
IsDefaultAttribute()	判斷目前的控制項產生器是否為預設值。
Match(Object)	在衍生類別中覆寫時，會傳回值，表示這個執行個體是否等於指定物件。 (繼承來源 Attribute)
MemberwiseClone()	建立目前 Object 的淺層複製。 (繼承來源 Object)
ToString()	傳回代表目前物件的字串。 (繼承來源 Object)

明確介面實作

_Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)	將一組名稱對應至一組對應的分派識別項 (Dispatch Identifier)。 (繼承來源 Attribute)
_Attribute.GetTypeInfo(UInt32, UInt32, IntPtr)	擷取物件的類型資訊，可以用來取得介面的類型資訊。 (繼承來源 Attribute)
_Attribute.GetTypeInfoCount(UInt32)	擷取物件提供的類型資訊介面數目 (0 或 1)。 (繼承來源 Attribute)
_Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)	提供物件所公開的屬性和方法的存取權。 (繼承來源 Attribute)

適用於

共用方式為

ControlBuilderAttribute 類別

定義

範例

備註

建構函式

欄位

屬性

方法

明確介面實作

適用於

另請參閱

其他資源