Imports System.Data.SqlClient
Class MainWindow
Private Sub BtnLogin_Click(sender As Object, e As RoutedEventArgs) Handles btnLogin.Click

End Sub

Sub CheckLogin()
    Dim RetVal As Integer
    Dim conn = New SqlConnection("Data Source=(localdb)MSSQLLocalDB;Initial Catalog=dbProject;Integrated Security=True")
    Using cmd = New SqlCommand("select count(*) from tblLogin where username = @Username and password= @Password;", conn)
        cmd.Parameters.Add("@Username", System.Data.SqlDbType.VarChar).Value = txtUsername.Text.Trim
        cmd.Parameters.Add("@Password", System.Data.SqlDbType.VarChar).Value = txtPassword.Text.Trim
        conn.Open()
        If conn.State = ConnectionState.Open Then
            RetVal = CInt(cmd.ExecuteScalar)
            If RetVal = 1 Then

            Else
                txtUsername.Clear()
                txtPassword.Clear()
                txtUsername.Focus()
            End If
        Else
            MessageBox.Show("The connection is not open, contact an administrator!")
            End
        End If
    End Using
End Sub
End Class