VB.NET Update và nhận giá trị Update không kịp

[tandangminh]

Imports System.Data.OleDb

Public Class Form1
Dim PathFileName As String = Application.StartupPath & "\db1.mdb"
Dim CnnMain As OleDbConnection

Sub Ketnoi_OleDb()
CnnMain = New OleDbConnection
CnnMain.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & PathFileName & ";Persist Security Info=False"
CnnMain.Open()
End Sub

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Call Ketnoi_OleDb()
End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnGan.Click
Dim myOleDbCommand As New OleDbCommand("UPDATE Table1 SET Col1=1234", CnnMain)
myOleDbCommand.ExecuteNonQuery()
End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnSuavaNhan.Click
Dim da As OleDbDataAdapter
Dim dt As DataTable

Dim myOleDbCommand As New OleDbCommand("UPDATE Table1 SET Col1=4", CnnMain)
myOleDbCommand.ExecuteNonQuery()

da = New OleDbDataAdapter("SELECT Col1 FROM Table1", CnnMain.ConnectionString)
dt = New DataTable
da.Fill(dt)

MsgBox(dt.Rows(0).Item("Col1"))
'Tai sao Ket qua la 1234 ma khong phai 4
End Sub
End Class