Using aspx controls in base class - asp.net

Question

I've got two aspx pages which are very similar and have various identical functions in the code behind. I'd like to create a base class which both the code behind classes derive from. Is it possible for the base class to access the controls on the aspx page. For instance:
class base
inherits System.Web.UI.Page
Sub prepareScreen()
'txtName is a text box on the aspx page
Me.txtName.text = "George"
end sub
end class
class codeBehind
inherits base
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
prepareScreen()
end sub
end class
Somewhat understandably the code fails to compile with:
'txtName' is not a member of 'clsbase'
Is it possible to link the two together?

Answer 1

You need to declare the control as a property of the base class. Then in the ASP markup, use the CodeFileBaseClass attribute.
The MSDN reference is no longer available.
class base
inherits System.Web.UI.Page
Protected Property txtName() As TextBox
Sub prepareScreen()
'txtName is a text box on the aspx page
Me.txtName.text = "George"
end sub
end class
class codeBehind
inherits base
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
prepareScreen()
end sub
end class
<%# page CodeFileBaseClass="base" inherits="codebehind" ... %>

Answer 2

It would be better if you refactor your code, so that you have no need to do something like this.
One better idea will be if you create a virtual method in the base class, which you can override in your child page(s), and set the value of your textbox, as you'll have an easy access to the textbox.

Answer 3

You could use FindControl, eg.
TextBox txtName=FindControl("txtName");
which would find the control on the rendered page even though it was rendered by the descendant class. Though this is breaking the point of OO and separation of function/data somewhat.

Answer 4

You can use ((TextBox)Page.FindControl("txtName")) to get the textbox. Be careful because if you use this base class else where the control might not exist

Answer 5

In response to your clarification:
You could Create a property:
protected TextBox txtName
{
get{return (TextBox)Page.FindControl("txtName");}
set{Page.FindControl("txtName") = vale;}
}
Or Create a Virtual property:
protected virtual TextBox txtName{get;set;}
In this case you would have to override it at your main class
protected override TextBox txtName{/*same as above*/}