Hi,

I'm trying to create my own custom control based on the textbox, but
with additional properties to specify whether or not the textbox is a
required field, and if its needs to be validated against a regular
expression. I'd also like it to change its backcolor and be focused on
if it's invalid.

Here is my current VB code:-

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

Public Class CustomTextBox
   Inherits TextBox

   Private req As RequiredFieldValidator
   Private reg As RegularExpressionValidator
   Dim _bgErrorColor As System.Drawing.Color
   Dim _required As Boolean
   Dim _regExp As String

   Protected Overloads Overrides Sub OnInit(ByVal e As EventArgs)

       req = New RequiredFieldValidator
       req.ControlToValidate = Me.ID
       req.ErrorMessage = "Value required for " & Me.ID
       req.Text = "*"

       reg = New RegularExpressionValidator
       reg.ControlToValidate = Me.ID
       reg.ErrorMessage = "Invalid value for " & Me.ID
       reg.Text = "*"
       If Me.RegExp <> "" Then reg.ValidationExpression = Me.RegExp

       Controls.Add(req)
       Controls.Add(reg)

   End Sub

   Protected Overloads Overrides Sub Render(ByVal w As HtmlTextWriter)
       MyBase.Render(w)
       If Me.Required Then req.RenderControl(w)
       If Me.RegExp <> "" Then reg.RenderControl(w)
   End Sub

   <Bindable(True), Category("Appearance"), DefaultValue("")> Property
[Required]() As Boolean
       Get
           Return _required
       End Get

       Set(ByVal Value As Boolean)
           _required = Value
       End Set
   End Property

   <Bindable(True), Category("Appearance"), DefaultValue("")> Property
[RegExp]() As String
       Get
           Return _regExp
       End Get

       Set(ByVal Value As String)
           _regExp = Value
       End Set
   End Property

   <Bindable(True), Category("Appearance"), DefaultValue("Red")>
Property [BgErrorColor]() As System.Drawing.Color
       Get
           Return _bgErrorColor
       End Get

       Set(ByVal Value As System.Drawing.Color)
           _bgErrorColor = Value
       End Set
   End Property

End Class

It seems to half work, but my required field validator does not appear
to the immediate right of my textbox, and if I put a validation summary
on my page, it shows the error message regardless of whether or not
i've specified the Required property of my control to true or false.

Does anyone know how i can get this to work, aswell as adding event
handlers or methods to set the focus to my control and make its
background color set to whatever i specify in my BgErrorColor property,
if the control is invalid?

Many thanks in advance for any suggestions

Dan Williams