How get the DataDirectory path for MS Access MDB file - vb.net

Question

I have code which asks the user for a folder path and then copies an MDB file to that folder for back-up. However, the MDB is being copied from the wrong folder. How can I fix it so that it uses the right data folder when backing-up and restoring the MDB?
Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click
Try
Dim fbd As New FolderBrowserDialog
If fbd.ShowDialog() = vbOK Then
System.IO.File.Copy("MHC.mdb", fbd.SelectedPath & "\MHC.mdb")
MsgBox("Done")
End If
Catch ex As Exception
MsgBox(ex.Message)
End Try
End Sub
Private Sub btnRestore_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRestore.Click
Try
Dim fbd As New FolderBrowserDialog
If fbd.ShowDialog() = vbOK Then
File.Delete("MHC.mdb")
System.IO.File.Copy(fbd.SelectedPath & "\MHC.mdb", "MHC.mdb")
MsgBox("Done")
Application.Restart()
End If
Catch ex As Exception
MsgBox(ex.Message)
End Try
End Sub

Answer 1

Yes I want to know the DataDirectory path.
The |DataDirectory| path placeholder as used in a connection string similar to this example:
Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|\Northwind.MDB
may be retrieved using code similar to this:
Dim objDataDir As Object = AppDomain.CurrentDomain.GetData("DataDirectory")
Dim dataDirectory As String = TryCast(objDataDir, String)
Beware that the above code can return Nothing (null) for dataDirectory. The only scenario that I know of that sets a "DataDirectory" is an application published using ClickOnce.
If dataDirectory is null, then you probably want to assign the Application.StartupPath property to it.
I do not know of any official documentation that states this is the proper procedure, but the code is based off of the ExpandDataDirectory method.
There is also a non-publicly scoped DataDirectory Property on the AppDomain.CurrentDomain.ActivationContext object, but you would need to use reflection to retrieve that property.
Note that if you want to use the |DataDirectory| placeholder, but point it to a path of your choice, you can use:
AppDomain.CurrentDomain.SetData("DataDirectory", "your path here")