How to show Document-viewer in c#.net(Windows)

using System;
using System.IO;
//using System.Windows.Controls;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Forms;
using System.Windows.Xps.Packaging;
using System.Xml;

namespace HelloXPSWorld {
  public partial class Form1: Form {
      DocumentViewer viewer;
      private System.Windows.Forms.TextBox txt;
    public Form1() {
      InitializeComponent();
    }

    private void Form1_Load(object sender,EventArgs e) {
      viewer = new DocumentViewer();
    XpsDocument xd = new XpsDocument("test.xps",FileAccess.ReadWrite);
     viewer.Document = xd.GetFixedDocumentSequence();
      viewer.Visibility = Visibility.Collapsed;
     bool bln = viewer.IsVisible;//here it is false
    viewer.BringIntoView();
    }
  }
}