Imports System
Imports System.Web
Imports System.Web.UI
Imports System.Collections
Imports System.Collections.Specialized

Namespace CustomWebFormsControls

    <System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.Demand, Name:="FullTrust")> Public Class MyTextBox
        Inherits Control
        Implements IPostBackDataHandler


        Public Property Text() As String
            Get
                Return CType(Me.ViewState("Text"), String)
            End Get

            Set
                Me.ViewState("Text") = value
            End Set
        End Property


        Public Event TextChanged As EventHandler


        Public Overridable Shadows Function LoadPostData( _
        postDataKey As String, _
        postCollection As System.Collections.Specialized.NameValueCollection) _
        As Boolean Implements IPostBackDataHandler.LoadPostData

            Dim presentValue As String = Text
            Dim postedValue As String = postCollection(postDataKey)

            If presentValue Is Nothing Or Not presentValue.Equals(postedValue) Then
                Text = postedValue
                Return True
            End If

            Return False
        End Function


        Public Overridable Shadows Sub RaisePostDataChangedEvent() _
        Implements IPostBackDataHandler.RaisePostDataChangedEvent

            OnTextChanged(EventArgs.Empty)
        End Sub


        Protected Overridable Sub OnTextChanged(e As EventArgs)
            RaiseEvent TextChanged(Me, e)
        End Sub


        Protected Overrides Sub Render(output As HtmlTextWriter)
            output.Write("<INPUT type= text name = " & Me.UniqueID & _
                " value = " & Me.Text & " >")
        End Sub

    End Class

End Namespace

using System;
using System.Web;
using System.Web.UI;
using System.Collections;
using System.Collections.Specialized;


namespace CustomWebFormsControls {

   [System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name="FullTrust")] 
   public class MyTextBox: Control, IPostBackDataHandler {


      public String Text {
         get {
            return (String) ViewState["Text"];
         }

         set {
            ViewState["Text"] = value;
         }
      }      


      public event EventHandler TextChanged;


      public virtual bool LoadPostData(string postDataKey, 
         NameValueCollection postCollection) {

         String presentValue = Text;
         String postedValue = postCollection[postDataKey];

         if (presentValue == null || !presentValue.Equals(postedValue)) {
            Text = postedValue;
            return true;
         }

         return false;
      }


      public virtual void RaisePostDataChangedEvent() {
         OnTextChanged(EventArgs.Empty);
      }


      protected virtual void OnTextChanged(EventArgs e) {
         if (TextChanged != null)
            TextChanged(this,e);
      }


      protected override void Render(HtmlTextWriter output) {
         output.Write("<INPUT type= text name = "+this.UniqueID
            + " value = " + this.Text + " >");
      }
   }   
}