Q:

How to create a WPF Window without a border and the window display complete?

I setting the window property ResizeMode="CanResize", WindowStyle="None",
but when the WindowState="Maximized",the left side display incomplete.
Very strange.
<Window x:Class="WpfApp24.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:WpfApp24"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800"
        AllowsTransparency="True"
        WindowStartupLocation="CenterScreen" 
        WindowState="Maximized"
        ResizeMode="CanResize"
        WindowStyle="None" 
        >
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="220"/>
            <ColumnDefinition Width="*"/>
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="38"/>
            <RowDefinition Height="*"/>
            <RowDefinition Height="25"/>
        </Grid.RowDefinitions>

        <TextBlock Text="navBarGroup1" Grid.Row="1" Grid.Column="0"/>

    </Grid>
</Window>

C# code
        public MainWindow()
        {
            InitializeComponent();

            this.MaxHeight = SystemParameters.MaximizedPrimaryScreenHeight;
            this.MaxWidth = SystemParameters.MaximizedPrimaryScreenWidth;
        }

here display uncomplete

A:

When you have WindowState="Maximized" and WindowStyle="None", the window extends beyond the actual edge of the screen by several pixels on all sides. When maximized, Windows crops the edges of the window to obscure what would normally be the resize edges.

Solution 1

Since you want the window to be maximized, and remove the style, the property ResizeMode="CanResize" is useless. 
If you set the property like this it will solve your problem:
ResizeMode="NoResize"

Full code of xaml:
<Window x:Class="WpfApp24.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:WpfApp24"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800"
        AllowsTransparency="True"
        WindowStartupLocation="CenterScreen" 
        WindowState="Maximized"
        ResizeMode="NoResize"
        WindowStyle="None" 
        >
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="220"/>
            <ColumnDefinition Width="*"/>
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="38"/>
            <RowDefinition Height="*"/>
            <RowDefinition Height="25"/>
        </Grid.RowDefinitions>

        <TextBlock Text="navBarGroup1" Grid.Row="1" Grid.Column="0"/>

    </Grid>
</Window>

Solution 2

Give a margin of 6 in you grid, to prevent elements fallout to the edges:
<Grid Margin="6">

Full code:
<Window x:Class="WpfApp24.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:WpfApp24"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800"
        AllowsTransparency="True"
        WindowStartupLocation="CenterScreen" 
        WindowState="Maximized"
        ResizeMode="CanResize"
        WindowStyle="None" 
        >
    <Grid Margin="6">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="220"/>
            <ColumnDefinition Width="*"/>
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="38"/>
            <RowDefinition Height="*"/>
            <RowDefinition Height="25"/>
        </Grid.RowDefinitions>

        <TextBlock Text="navBarGroup1" Grid.Row="1" Grid.Column="0"/>

    </Grid>
</Window>

