I am new to WPF , i can't find a way to open a new WPF window on the same main WPF app i tried Frame method , here is the code :-
<Window x:Class="WPF_FINAL.MainWindow"
        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:WPF_FINAL"
        mc:Ignorable="d"
        xmlns:materialDesign="http://materialdesigninxaml.net/winfx/xaml/themes"
        TextElement.Foreground="{DynamicResource MaterialDesignBody}"
        TextElement.FontWeight="Regular"
        TextElement.FontSize="13"
        TextOptions.TextFormattingMode="Ideal"
        TextOptions.TextRenderingMode="Auto"
        Background="{DynamicResource MaterialDesignPaper}"
        Height="768"
        Width="1366"
        WindowState="Maximized"
        Title="MainWindow">
    <Grid Background="#dff9fb"
          Margin="33,10,-33,-10">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="20" />
            <ColumnDefinition Width="13.5" />
            <ColumnDefinition Width="152" />
            <ColumnDefinition Width="auto"
                              MinWidth="335.5" />
            <ColumnDefinition />
            <ColumnDefinition Width="20" />
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="20" />
            <RowDefinition Height="auto" />
            <RowDefinition Height="auto" />
            <RowDefinition Height="auto" />
            <RowDefinition Height="*" />
            <RowDefinition Height="20" />
        </Grid.RowDefinitions>
        <Frame Margin="0,0,0.5,10"
               Grid.ColumnSpan="5"
               x:Name="main"
               Grid.RowSpan="6">
        </Frame>
    </Grid>
</Window>
cs code
            main.Content = new Window1();
but when i run it gives me break exception i tried also navigation service but i found it's only associated with Pages any suggestion how to do this ? thank you