myfirstcontrol.vb

This is a book about vb.you could learn this from this book

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

Namespace WroxControls 

	Public Class MyFirstControlPB
		Inherits Control
		Implements IPostBackEventHandler

		Public Property Number As Integer
		
			Get
				If Not (ViewState("Number") Is Nothing) Then
					return ViewState("Number")
				End If
				return 50
			End Get

			Set
				ViewState("Number") = value
			End Set
			
		End Property


		Protected Overloads Sub RaisePostBackEvent(eventArgument As String) Implements IPostBackEventHandler.RaisePostBackEvent
		
			If eventArgument = "inc" Then
				Number += 1
			End If

			If eventArgument = "dec" Then
				Number -= 1
			End If

		End Sub
		
		
		Protected Overrides Sub Render(writer As HtmlTextWriter)
		
			writer.Write("The Number is " & Number.ToString() & " (" )

			writer.Write("<a href=""javascript:" _ 
				& Page.GetPostBackEventReference(Me,"inc") _
				& """>Increase Number</a>")

			writer.Write(" or " )

			writer.Write("<a href=""javascript:" _
				& Page.GetPostBackEventReference(Me,"dec") _
				& """>Decrease Number)</a>")
	
		End Sub
			
	End Class
	
End Namespace