Problem with XmlDocument deleting import prefixes.

Question

I create a xml document and try to get the string out of it like this:

string path = "c:\temp\window.xaml";
FileStream stream = new FileStream(@path, FileMode.Open);
XmlDocument doc = new XmlDocument();
doc.Load(stream);

string insideString = doc.FirstChild.OuterXml;

Here is the content of a window.xaml file:

<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"  mc:Ignorable="d"
 x:Name="Window"
 Title="MainWindow"
 Width="1024" Height="768">
<Grid/>
</Window>

However, the content of a string insideString from the code above does not match this xaml file. It looks like this:

<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"  Ignorable="d"
     x:Name="Window"
     Title="MainWindow"
     Width="1024" Height="768">
    <Grid/>
    </Window>

The difference is in the mc:Ignorable and Ignorable. The mc: prefix is missing in the output. Is there a way, how to prevent the Xml Document from deleting this prefix?

Thanks for any answer