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Control.AddParsedSubObject(Object) Method

  • Reference

Definition

Namespace:
System.Web.UI
Assembly:
System.Web.dll

Notifies the server control that an element, either XML or HTML, was parsed, and adds the element to the server control's ControlCollection object.

protected:
 virtual void AddParsedSubObject(System::Object ^ obj);
protected virtual void AddParsedSubObject (object obj);
abstract member AddParsedSubObject : obj -> unit
override this.AddParsedSubObject : obj -> unit
Protected Overridable Sub AddParsedSubObject (obj As Object)

Parameters

obj
Object

An Object that represents the parsed element.

Examples

The following example is a custom server control that uses the AddParsedSubObject method to determine if elements declared between the opening and closing tags of this control are TextBox Web server controls. If they are, they are added to an ArrayList object, items. When the overridden CreateChildControls method is called, it iterates through the ArrayList and adds each object in it to the ControlCollection of the custom server control.

Important

This example has a text box that accepts user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview.

// Custom ControlBuilder class. Interprets nested tag name "myitem" as a textbox. 
public class MyControlBuilder : ControlBuilder 
{
   public override Type GetChildControlType(String tagName,
                                       IDictionary attributes)
   {
      if (String.Compare(tagName, "myitem", true) == 0) 
      {
         return typeof(TextBox);
      }
      return null;
   }
}

[ 
ControlBuilderAttribute(typeof(MyControlBuilder)) 
]
public class MyControl : Control
{
   // Store all the controls specified as nested tags.
   private ArrayList items = new ArrayList();
   
   // This function is internally invoked by IParserAccessor.AddParsedSubObject(Object).
   protected override void AddParsedSubObject(Object obj) 
   {
      if (obj is TextBox) 
      {
         items.Add(obj);
      }
   }

   // Override 'CreateChildControls'. 
   protected override void CreateChildControls()
   {
      System.Collections.IEnumerator myEnumerator = items.GetEnumerator();
      while(myEnumerator.MoveNext())
          this.Controls.Add((TextBox)myEnumerator.Current);
   }
}    

' Custom ControlBuilder class. Interprets nested tag name "myitem" as a textbox.
Public Class MyControlBuilder
   Inherits ControlBuilder

   Public Overrides Function GetChildControlType(tagName As String, _
                             attributes As IDictionary) As Type
      If String.Compare(tagName, "myitem", True) = 0 Then
         Return GetType(TextBox)
      End If
      Return Nothing
   End Function
End Class

<ControlBuilderAttribute(GetType(MyControlBuilder))> Public Class MyControl
   Inherits Control
   ' Stores all the controls specified as nested tags.
   Private items As New ArrayList()

   ' This function is internally invoked by IParserAccessor.AddParsedSubObject(Object).
   Protected Overrides Sub AddParsedSubObject(obj As Object)
      If TypeOf obj Is TextBox Then
         items.Add(obj)
      End If
   End Sub

  ' Override 'CreateChildControls'.
   Protected Overrides Sub CreateChildControls()
      Dim myEnumerator As System.Collections.IEnumerator = items.GetEnumerator()
      While myEnumerator.MoveNext()
         Me.Controls.Add(CType(myEnumerator.Current, TextBox))
      End While
   End Sub
End Class

Remarks

Unless you override it, this method automatically adds LiteralControl objects to the server control's ControlCollection object. This collection is accessible through Control.Controls property.

Applies to

See also