Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim b As String = ""

        If TextBox1.Text = "" Or TextBox2.Text = "" Then
            MsgBox("Data tidak lengkap", MsgBoxStyle.Information, "Login")
        Else
            conect = "select * from tbl_id"
            cmd = New SqlCommand(conect)
            dr = cmd.ExecuteReader()
            Try
                While dr.Read
                    If TextBox1.Text = dr("id") And TextBox2.Text = dr("pass") Then
                        b = "Ya"
                        Exit While
                    End If
                End While
                If b = "Ya" Then

                    Me.Hide()
                Else
                    MsgBox("ID Karyawan atau Password tidak ditemukan", MsgBoxStyle.OkOnly, "Login")
                End If
            Catch ex As Exception
                MsgBox(ex.Message)

            End Try
            dr.Close()

        End If
    End Sub

Your program is incomplete. See the database section (Chapter 13) of this tutorial

You didn't set the connection string. There is the same problem, just search this forum.