สอบถาการ connect database โดยสร้างไฟล์ฐานข้อมูลที่ตัว Project vb.net เลยครับ

  Private _duration As Integer
    ' Private conStr As String = "Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\dtEmployee.mdf;Integrated Security=True;User Instance=Ture"
    Private conStr As String = "Data Source=SED32\SQLEXPRESS;AttachDbFilename=|DataDirectory|\dtEmployee.mdf;Integrated Security=True;uid=sa; pwd=matco1234;"

    Private mycon As SqlConnection
    Private Sub Form3_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        Try
            mycon = New SqlConnection(conStr)

            If mycon.State = ConnectionState.Closed Then
                mycon.Open()
            End If
        Catch ex As Exception
            MsgBox("Invalid connectionString")
        End Try

        sizeFont()
        btnStart.Enabled = True
        btnStop.Enabled = False

        txtNum1.[ReadOnly] = True
        txtNum2.[ReadOnly] = True
        txtNum3.[ReadOnly] = True
        txtNum4.[ReadOnly] = True


    End Sub