controls positions missed when maximized window in WPF - wpf

Question

I was dragged the controls on the form and when i run it and maximized the window the controls don't keep on the same place which i put it on.
how to keep controls in the same place when the window is maximized ??
this is the XAML code:
<Window x:Class="Wpf_App1.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_App1"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<Grid>
<Grid.Background>
<ImageBrush/>
</Grid.Background>
<Grid HorizontalAlignment="Left" Height="319" VerticalAlignment="Top" Width="517">
<Image x:Name="image" HorizontalAlignment="Left" Height="319" VerticalAlignment="Top" Width="517" Stretch="Fill" Source="C:\Users\Moath\OneDrive\Documents\Visual Studio 2015\Projects\Wpf_App1\Wpf_App1\Images\LoginScr.jpg"/>
<Grid HorizontalAlignment="Left" Height="52" Margin="310,112,0,0" VerticalAlignment="Top" Width="122">
<Grid.RowDefinitions>
<RowDefinition Height="1*" />
<RowDefinition Height="1*" />
</Grid.RowDefinitions>
<TextBox x:Name="textBox" HorizontalAlignment="Left" TextWrapping="Wrap" Text="TextBox" VerticalAlignment="Top" Height="16" Width="120
" Margin="0,10,0,0" >
<TextBox.Background>
<ImageBrush Stretch="None"/>
</TextBox.Background>
</TextBox>
<TextBox x:Name="textBox1" HorizontalAlignment="Left" Margin="0,10,0,0" Grid.Row="1" TextWrapping="Wrap" Text="TextBox" VerticalAlignment="Top" Height="16
" Width="120
" >
<TextBox.Background>
<ImageBrush Stretch="None"/>
</TextBox.Background>
</TextBox>
</Grid>
</Grid>
</Grid>
</Window>

Answer 1

EDIT in your 3rd Inner Grid you are setting Margin="310,112,0,0" that is the cause of your problem. The Margin is work like this Margin="left,top,right,bottom" so you set the left Margin to 310 and top Margin to 112 that is why the textbox not in top left always. try to set the Margin to 0.
so it will look like this:
<Grid HorizontalAlignment="Left" Height="52" Margin="0" VerticalAlignment="Top" Width="122">