ASP.NET - Add Validator to Dynamically Created Control

Dim objValidator As New RegularExpressionValidator()

objValidator.ControlToValidate = txtItem.ClientID

objValidator.ValidationExpression = "[0-9]"

objValidator.Text = "*"

objValidator.ErrorMessage = "Must be in correct format"

objValidator.SetFocusOnError = True

phPlaceholder.Controls.Add(objValidator)