Change the text in a field with a VBA function - database

Question

I'm currently working on a database in Access which has a table (Pro_Cons) who compares the pros and cons of different product-types. This table has 3 columns; Type (Product_type), Pros (Pro) and Cons.
For each of product-type I created a form which includes the pro- and the cons-field of the according type out of this table.
For adding new text to this fields I'm creating a VBA-function which is triggered by a button-click.
Because nothing worked as supposed to, I created the following function, which should only replace the Pro -field of the product type1 to change1.
Access doesnt throw an error, but nothing changes in the table.
Has someone an idea whats happening here?
Sub Change_Pos_Inf()
Dim db As DAO.Database
Dim rst As DAO.Recordset
Dim strSQL As String
Dim strSensortyp As String
Dim strNew As String
Set db = CurrentDb()
strProduct_type = "type1"
strNew = "change1"
strSQL = "SELECT Pro FROM Pro_Cons WHERE Product_type='strProduct_type';"
Set rst = db.OpenRecordset(strSQL, dbOpenDynaset)
With rst
If .RecordCount > 0 Then
.MoveFirst
.Edit
!Pro.Value = strNew
.Update
End If
End With
End Sub

Answer 1

I think your literal should be changed to reference a form control:
strSQL = "SELECT Pro FROM Pro_Cons WHERE Product_type='strProduct_type';"
Changes to:
strSQL = "SELECT Pro FROM Pro_Cons WHERE Product_type='" & Me!strProduct_type &
"'";

Answer 2

Please try the following code. It corrects your WHERE clause:
Sub Change_Pos_Inf()
Dim db As DAO.Database
Dim rst As DAO.Recordset
Dim strSQL As String
Dim strSensortyp As String
Dim strNew As String
Set db = CurrentDb()
strProduct_type = "type1"
strNew = "change1"
strSQL = "SELECT Pro FROM Pro_Cons WHERE Product_type= '" & strProduct_type & "';"
Set rst = db.OpenRecordset(strSQL, dbOpenDynaset)
With rst
If Not rst.EOF Then
.Edit
!Pro.Value = strNew
.Update
Else
MsgBox "No Record found!!"
End If
End With
rst.Close
Set rst = Nothing
End Sub