WPF Open New Form problem

A WPF Form, I use C#;


I have a window named "MainWindow_1" and another named"MainWindow_2",

in MainWindow_1 I have a button to open "MainWindow_2". My codes are:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using DevExpress.Xpf.Core;
using DevExpress.Xpf.Ribbon;
using DevExpress.Xpf.Bars;
using namespace.DXWPFApplication3;

namespace DXWPFApplication16 
 
{
    public partial class MainWindow_1 : DXRibbonWindow
    {
        public MainWindow_1()
        {
            InitializeComponent();

        }

        private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            

        }

        private void Button_Click_2(object sender, RoutedEventArgs e)
        {

           MainWindow_2 win2 = new MainWindow_2.Show();
           win2.Show();
//I want this button opens another WPF form (which namespace DXWPFApplication3)//
            

        }

    }


}
();

But VS2012, underlines "MainWindow_2" word.It says "Type or namespace couldn't be found"

How can i solve it?

Thanks.

Tags: C#, Visual Studio 2012, DevExpress