Loop through controls in Panel with MasterPage

Hi,


I am trying to use the following code to loop through and find all the Textboxes in a Panel.
all the controls are located in the content page and I am using a master page.
I am not recieving an Error but the code is not working as it should


For Each mControl As Control In pnlClientsMaster.Controls
If TypeOf mControl Is TextBox Then
Response.Write("testing here")
Dim txt As TextBox = mControl
txt.Text = "testing"
txt.BackColor = Drawing.Color.Blue
End If
Next

Just to get it going I am trying to change every textbox to have "testing" as the text and a new back color.
my requirement for using this code is to recycle the textboxes and use them as view only.  yellow borders when I press the edit linkbutton et ...