Linq-to-SQL SubmitChanges not updating physical database - database

Question

I am new here and only signed up because I desperately need the solution to my problem. I have a VB.NET project that is using a local .MDF file that I have imported into my project. The primary keys are intact so I know that isn't my issue.
I am using Linq-to-SQL to query the database and make changes. On my main form I use a Data Grid View that is populated by a query. I am having an issue with my insert where the query works fine and the DGV gets updated with newly created data, but when I call SubmitChanges() the changes do not get saved to the actual physical database. I am not sure what I am missing or doing wrong.
Here is my code to better assist your educated answer.
Public Class frmCell_Leader
'Reference DataContext
Private db As New MarquardtClassesDataContext()
Private Sub frmCell_Leader_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
FillProductionGrid()
PrepareInsertFields()
End Sub
Private Sub FillProductionGrid()
''''''''''''''''''''''''''''''''''
'E.Salce Last Modified 11.29.2012
'Comments: Working
''''''''''''''''''''''''''''''''''
'Populate DGV
Dim query = From marq In db.tblProductivities
Select
marq.PartNum, marq.Produced, marq.Packed, marq.Issue, marq.StationNum, _
marq.PlanDownTime, marq.UnplannedDownTime, marq.CurDate
dgvProduction.DataSource = query
End Sub
Private Sub PrepareInsertFields()
''''''''''''''''''''''''''''''''''
'E.Salce Last Modified 11.29.2012
'Comments: Working
''''''''''''''''''''''''''''''''''
'Fill Planned Downtime Combo Box
Dim PlannedQuery = From planned In db.tblPlannedDownTimes
Select planned.Plan_ID, planned.Description, planned.Active
Where Active = True
cboPlanned.DataSource = PlannedQuery
cboPlanned.DisplayMember = "Description"
cboPlanned.ValueMember = "Plan_ID"
'Fill UnPlanned Downtime Combo Box
Dim UnPlannedQuery = From unplanned In db.tblUnplannedDownTimes
Select unplanned.Unplan_ID, unplanned.Description, unplanned.Active
Where Active = True
cboUnplanned.DataSource = UnPlannedQuery
cboUnplanned.DisplayMember = "Description"
cboUnplanned.ValueMember = "UnPlan_ID"
End Sub
Private Sub btnAdd_Click(sender As System.Object, e As System.EventArgs) Handles btnAdd.Click
'Add the new Production to database
'Create an productivity object
Dim marqpro As New tblProductivity With {
.PartNum = CShort(txtPartNumber.Text),
.Produced = CShort(txtProduced.Text),
.Packed = CShort(txtPacked.Text),
.Issue = txtIssue.Text,
.PlanDownTime = CShort(cboPlanned.SelectedValue),
.UnplannedDownTime = CShort(cboUnplanned.SelectedValue),
.CurDate = Date.Today}
'insert newly created data
Try
'Submit changes too database
db.tblProductivities.InsertOnSubmit(marqpro)
db.SubmitChanges()
db.Refresh(Data.Linq.RefreshMode.KeepCurrentValues, marqpro)
'Refresh DGV
FillProductionGrid()
MessageBox.Show("Data added successfully")
Catch ex As Exception
MessageBox.Show("Error: " & ex.Message)
End Try
End Sub
End Class

Answer 1

Perhaps you have an .mdf file in your project that is getting copied to the bin/debug folder everytime you build.
Why isn't my SubmitChanges() working in LINQ-to-SQL?