c# - WPF Navigate to other page -

i want navigate between pages

public partial class mainwindow : window {     public mainwindow()     {         initializecomponent();     }      private void routeitems(object sender, routedeventargs e)     {         navigationservice nav = navigationservice.getnavigationservice(this);         nav.navigate(new itemspage());     } } 

getnavigationservice returns null

<window x:class="special.mainwindow"         name="window"                           xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"         xmlns:local="clr-namespace:special"         mc:ignorable="d"         title="mainwindow" windowstate="maximized">  <button content="go" click="routeitems"/> </window> 

i don't want use other method (changing content).

edit

this.navigationservice undefined

you need to, first add frame xaml:

<grid >       <grid.rowdefinitions>           <rowdefinition height="*"/>           <rowdefinition height="auto"/>       </grid.rowdefinitions>    <frame x:name="mainframe"></frame>     <button content="go" click="routeitems" grid.row="1"/>  </grid> 

then after add xaml pages, use mainframe navigate:

 private void routeitems(object sender, routedeventargs e)     {         mainframe.navigationservice.navigate(new uri("page1.xaml", urikind.relativeorabsolute));     }