<UserControl ...
       ...>
  <Grid>
    <DocumentViewer x:Name="documentViewer"/>
  </Grid>
</UserControl>

<!--隐藏DocumentViewer边框-->
<UserControl.Resources>
  <Style x:Key="{x:Type DocumentViewer}" TargetType="{x:Type DocumentViewer}">
    <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.WindowTextBrushKey}}" />
    <Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}" />
    <Setter Property="FocusVisualStyle" Value="{x:Null}" />
    <Setter Property="Template">
      <Setter.Value>
        <ControlTemplate TargetType="{x:Type DocumentViewer}">
          <Border BorderThickness="{TemplateBinding BorderThickness}" BorderBrush="{TemplateBinding BorderBrush}" Focusable="False">
            <Grid KeyboardNavigation.TabNavigation="Local">
              <Grid.Background>
                <SolidColorBrush Color="{DynamicResource ControlLightColor}" />
              </Grid.Background>
              <Grid.RowDefinitions>
                <RowDefinition Height="Auto" />
                <RowDefinition Height="*" />
                <RowDefinition Height="Auto" />
              </Grid.RowDefinitions>
              <ScrollViewer Grid.Row="1" CanContentScroll="true" HorizontalScrollBarVisibility="Auto" x:Name="PART_ContentHost" IsTabStop="true">
                <ScrollViewer.Background>
                  <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                    <GradientStop Color="{DynamicResource ControlLightColor}" Offset="0" />
                    <GradientStop Color="{DynamicResource ControlMediumColor}" Offset="1" />
                  </LinearGradientBrush>
                </ScrollViewer.Background>
              </ScrollViewer>
            </Grid>
          </Border>
        </ControlTemplate>
      </Setter.Value>
    </Setter>
  </Style>
</UserControl.Resources>

  //ElementHost
  private System.Windows.Forms.Integration.ElementHost elementHost1;
  //XpsPreviewer变量
  private WPF.XpsPreviewer xpsPreviewer1;

  private void InitializeComponent()
  {
    this.elementHost1 = new System.Windows.Forms.Integration.ElementHost();
    this.xpsPreviewer1 = new WPF.XpsPreviewer();

    //初始化
    //其他属性初始化...
    this.elementHost1.Child = this.xpsPreviewer1;
    //其他属性初始化...
  }

  /// <summary>
  /// 加载XPS文件
  /// </summary>
  /// <param name="fileName">XPS文件名</param>
  internal void LoadXps(string fileName)
  {
    var xpsDocument = new XpsDocument(fileName, FileAccess.Read);
    this.xpsPreviewer1.documentViewer.Document = xpsDocument.GetFixedDocumentSequence();
    xpsDocument.Close();
  }

  /// <summary>
  /// 将Excel文件转换为XPS文件
  /// </summary>
  /// <param name="execelFileName">Excel文件名</param>
  /// <param name="xpsFileName">转换的xps文件名</param>
  public void ConvertExcelToXps(string excelFileName, string xpsFileName)
  {
    if (string.IsNullOrWhiteSpace(excelFileName))
      throw new ArgumentNullException(excelFileName);
    if (string.IsNullOrWhiteSpace(xpsFileName))
      throw new ArgumentNullException(xpsFileName);

    var fileInfo = new FileInfo(xpsFileName);
    if (!fileInfo.Directory.Exists)
      fileInfo.Directory.Create();

    //删除已存在的文件
    if (File.Exists(xpsFileName))
      File.Delete(xpsFileName);

    Excel.Application app = new Excel.Application();
    app.DisplayAlerts = false;
    Excel.Workbooks wbs;
    Excel.Workbook wb;

    wbs = app.Workbooks;
    wb = wbs.Add(excelFileName);
    dynamic Nothing = System.Reflection.Missing.Value;
    wb.ExportAsFixedFormat(Excel.XlFixedFormatType.xlTypeXPS, xpsFileName, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing);
    wb.Close(true);
    wbs.Close();
    app.Quit();
    KillExcelProcess(app);
  }

  [DllImport("User32.dll")]
  private static extern int GetWindowThreadProcessId(IntPtr hWnd, out int ProcessId);

  /// <summary>
  /// 结束Excel进程
  /// </summary>
  /// <param name="obj"></param>
  private void KillExcelProcess(Excel.Application app)
  {
    if (app == null)
      return;
    try
    {
      IntPtr intptr = new IntPtr(app.Hwnd);
      int id;
      GetWindowThreadProcessId(intptr, out id);
      var p = Process.GetProcessById(id);
      p.Kill();
    }
    catch { }
  }