adressing object by variable - vba

Question

In my form I have a number of 8 text fields named with consecutive numbers (tbx_MyID1 to tbx_MyID8). I want to loop through all 8 text fields to create new records out of the text fields' values. So I am trying to store the text fields names in a variable and address the text fields by this variable. This only creates an error, saying the object does not exist.
Private Sub btn_Enter_Click()
Dim db As Database
Dim rs As Recordset
Set db = CurrentDb
Set rs = db.OpenRecordset("tbl")
Dim x As Integer
x = 1
While x < 9
Dim y As String
y = "tbx_MyID" & x
rs.AddNew
rs.Fields("ID") = Me!y.Value
x = x+1
Wend
rs.Update
rs.Close
Set rs = Nothing
db.Close
End Sub

Answer 1

Replace rs.Fields("ID") = Me!y.Value
with rs.Fields("ID") = Me.Controls("tbx_MyID" & x)
It will work because the default property of the underlying control type (a text box) is the "Text" property.
There are a lot of ways to reference controls dynamically on a form. It might be clearer to declare a variable for the text box, get a reference to it, and then specifically reference the Text property:
Dim ctl As TextBox
Dim x As Integer
x = 1
While x < 9
ctl = Me.Controls("tbx_MyID" & x)
rs.AddNew
rs.Fields("ID") = ctl.Text
x = x+1
Wend

Answer 2

As noted previously, you need to access the form's Controls property.
Additionally, you probably want to store your text box prefix and the number of text boxes in constants, to make your code more readable.
Finally, even Microsoft suggests you replace While...Wend loops with the Do...Loop construct. So updated code might look something like this:
Option Explicit
Private Const TEXT_BOX_PREFIX As String = "tbx_MyID"
Private Const TEXT_BOX_COUNT As Integer = 8
Private Sub Command18_Click()
Dim x As Integer
Dim txtBox As Access.TextBox
For x = 1 To TEXT_BOX_COUNT
Set txtBox = Me.Controls(TEXT_BOX_PREFIX & x)
Debug.Print txtBox.Value
' put your code to add/update records here.
Next x
End Sub
If you clarify your question to indicate how specifically the text boxes relate to new records, I can update my answer to address that part.