My app installed in two system and access the data from txt file from a remote location/system.sql server compact(.sdf) file as database. After installation it is ok fine. But updation not happening. How to clear or refresh the sdf file to null.if tge sdf file to be null it will read from txt. Dataset.Reset command shows error.both app to be updated after reopen. Not preferring the delete command because the ID numbering will change. How it possible? Please give me a suggestion/solution. Thanks

What I have tried:

  1  Imports System.Data.SqlServerCe
  2  Imports System.Data
  3  Imports System.IO
  4  
  5  Public Class Form1
  6      Dim CONN As New SqlCeConnection("Data Source=|DataDirectory|\Contactdb.sdf")
  7      Dim CMD As SqlCeCommand
  8      Dim DA As SqlCeDataAdapter
  9      Dim TABLE As DataTable
 10      Dim SRDR As StreamReader
 11      Dim SWR As StreamWriter
 12  
 13      Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
 14          If CONN.State = ConnectionState.Closed Then
 15              CONN.Open()
 16          End If
 17          If Not My.Computer.FileSystem.DirectoryExists(DIRECTORY) Then My.Computer.FileSystem.CreateDirectory(DIRECTORY)
 18          End If
 19          If Not System.IO.File.Exists(fname) Then
 20              System.IO.File.CreateText(fname)
 21          End If
 22  
 23          dgv1.Rows.Clear()
 24  
 25  SRDR = New IO.StreamReader(fname)
 26          While SRDR.Peek <> -1
 27              txt1 = SRDR.ReadLine()
 28              TXT = txt1.Split(vbTab)
 29              STR = "INSERT INTO Contactdb(Name,[Mobile],Office) VALUES ('" & TXT(0) & "','" & TXT(1) &"','" & TXT(2) & "')"
 30              CMD = New SqlCeCommand(STR)
 31              CMD.Connection = CONN
 32              CMD.ExecuteNonQuery()
 33          End While
 34          SRDR.Close() 
 35      End Sub
 36  
 37      Private Sub btnsave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnsave.Click
 38          STR = "INSERT INTO Contactdb(Name,[Mobile],Office)VALUES ('" & txtname.Text & "','" & txtmob.Text & "',,'" & txtoff.Text & "')"
 39          CMD = New SqlCeCommand(STR, CONN)
 40          CMD.ExecuteNonQuery() 
 41          MsgBox("Contact of " & txtname.Text & " Saved", vbExclamation, "SAVE")
 42  
 43  Dim wr As New StreamWriter(fname)
 44          Dim RC As Integer = dgv1.Rows.Count
 45          Dim CC As Integer = dgv1.Columns.Count
 46          For i As Integer = 0 To RC - 2 Step +1
 47              For j As Integer = 0 To CC - 1 Step +1
 48                  wr.Write(dgv1.Rows(i).Cells(j).Value & vbTab) 
 49              Next
 50              wr.Write(wr.NewLine)
 51          Next
 52          wr.Close()
 53      End Sub