ControlBuilderAttribute Class
 
System_CAPS_noteNote

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Specifies a ControlBuilder class for building a custom control within the ASP.NET parser. This class cannot be inherited.

Namespace:   System.Web.UI
Assembly:  System.Web (in System.Web.dll)

SystemObject
   SystemAttribute
    System.Web.UIControlBuilderAttribute

[AttributeUsageAttribute(AttributeTargets.Class)]
public sealed class ControlBuilderAttribute : Attribute
[AttributeUsageAttribute(AttributeTargets::Class)]
public ref class ControlBuilderAttribute sealed : Attribute
[<Sealed>]
[<AttributeUsageAttribute(AttributeTargets.Class)>]
type ControlBuilderAttribute = 
    class
        inherit Attribute
    end
<AttributeUsageAttribute(AttributeTargets.Class)>
Public NotInheritable Class ControlBuilderAttribute
	Inherits Attribute
NameDescription
System_CAPS_pubmethod ControlBuilderAttribute

This API supports the product infrastructure and is not intended to be used directly from your code. Specifies the control builder for a custom control.

NameDescription
System_CAPS_pubproperty

Gets the Type of the control associated with the attribute. This property is read-only.

System_CAPS_pubproperty

When implemented in a derived class, gets a unique identifier for this Attribute.(Inherited from Attribute.)

NameDescription
System_CAPS_pubmethod Equals

This API supports the product infrastructure and is not intended to be used directly from your code. Gets a value indicating whether the current ControlBuilderAttribute is identical to the specified object. (Overrides AttributeEquals.)

System_CAPS_pubmethod GetHashCode

This API supports the product infrastructure and is not intended to be used directly from your code. Returns the hash code of the ControlBuilderAttribute object. (Overrides AttributeGetHashCode.)

System_CAPS_pubmethod GetType

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethod IsDefaultAttribute

This API supports the product infrastructure and is not intended to be used directly from your code. Determines whether the current control builder is the default.(Overrides AttributeIsDefaultAttribute.)

System_CAPS_pubmethod Match

When overridden in a derived class, returns a value that indicates whether this instance equals a specified object.(Inherited from Attribute.)

System_CAPS_pubmethod ToString

Returns a string that represents the current object.(Inherited from Object.)

NameDescription
System_CAPS_pubfield System_CAPS_static Default

This API supports the product infrastructure and is not intended to be used directly from your code. Specifies the new ControlBuilderAttribute object. By default, the new object is set to null. This field is read-only.

NameDescription
System_CAPS_pubinterface System_CAPS_privmethod _AttributeGetIDsOfNames

Maps a set of names to a corresponding set of dispatch identifiers.(Inherited from Attribute.)

System_CAPS_pubinterface System_CAPS_privmethod _AttributeGetTypeInfo

Retrieves the type information for an object, which can be used to get the type information for an interface.(Inherited from Attribute.)

System_CAPS_pubinterface System_CAPS_privmethod _AttributeGetTypeInfoCount

Retrieves the number of type information interfaces that an object provides (either 0 or 1).(Inherited from Attribute.)

System_CAPS_pubinterface System_CAPS_privmethod _AttributeInvoke

Provides access to properties and methods exposed by an object.(Inherited from Attribute.)

This attribute specifies the builder Type to be used to create a custom control as shown in the following code:

[ControlBuilderAttribute(typeof(ControlBuilderType))]

The following code example creates a customized selection list that is used to display a message based on the SelectedIndex and the Message values defined at run time. The following command line is used to build the executable.

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
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 'MyVB_Item

   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 'CustomParseControlBuilder

   <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 'AddParsedSubObject

      <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 'Render
   End Class 'MyVB_CustomParse 

End Namespace 'CustomControls

The following example uses the custom control defined above. In particular, it assigns the SelectedIndex and Message values at run time to determine the message to be rendered. Notice that the values shown in the Register directive reflect the previous command line.

<%@ 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>
.NET Framework
Available since 1.1

Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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