I not entirely sure if this is what you are asking (Tell me if I am wrong) however if I need to isolate the contents of a field for checking purposes I usually use
if me.fieldname= "Yourinfohere" then ...
in the Form_Current() method. This will isolate the context of the textbox/combobox being used. For check boxes use true/false as necessary.
Below are a couple of examples
If Me.Loggedin_txt = "Usernamehere" Then
'If so then allow new users button
Me.NewUser_btn.Visible = True
Me.NewUser_lbl.Visible = True
<h3> Example 2 checkboxes</h3>
If recClone.RecordCount = 0 Then
MsgBox "There is no one to be billed this month"
'If to see if the URL expiry is within next month, add to bill.
If Me.NextRenewel_URL <= Date + 31 Then
BillTotal = Me.CostPA
BillTotal = 0
'more code here
Alright it's crude, probably not the most efficient way of doing things, but it works. If anyone else reading this knows more efficient ways of checking data, please let me know.
If however you want to edit control source based on the contents of a text box try this (Once again crude, and almost certainly not totally efficient)
If Me.ClientName = "fhjk" Then
Me.Text1.ControlSource = "= DomainName" 'Due to fact its a text field
Me.Text1.ControlSource = "=" & ExtentionNumber 'not text field therefore no need
David Thorne, Student