By default, the visual designer of a tool such as Visual Studio, creates an empty tag. This is a tag representing a control in its default state, when the control is dropped from the toolbox of a visual designer onto the design surface. To specify initial default values, a control can make use of this attribute. You can use this attribute to customize the initial HTML content that is placed in the designer when the control is dragged from the toolbox onto the form.

[ ToolboxData("<{0}:MyLabel runat= server Text= 
       MyLabel><{0}:MyLabel>") ]public class MyLabel : Label {...}

In the following code example, the previous code sets several properties specific to MyLabel. All occurrences of {0} are replaced, by the designer, with the tag prefix associated with the MyLabel class.

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


Namespace CustomControls
  <ToolboxData("<{0}:MyLabel Text='MyLabel' BorderColor='Yellow' BackColor='Magenta' BorderWidth = '10'  runat='server'></{0}:MyLabel>")>  _
  Public Class MyLabel
    Inherits Label

    Public Sub New()
      'Your code goes here.
    End Sub 'New

  End Class 'MyLabel

End Namespace 'CustomControls




    

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


namespace CustomControls
{

  [ ToolboxData("<{0}:MyLabel Text='MyLabel' BorderColor='Yellow' BackColor='Magenta' BorderWidth = '10'  runat='server'></{0}:MyLabel>") ]	
  public class MyLabel : Label 
  {
    public  MyLabel()
    { 
      // Your code goes here.
    } 
  }

}



    

.NET Framework

Windows 8 Consumer Preview, Windows Server 8 Beta, Windows 7, Windows Server 2008 SP2, Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Reference

Other Resources