Problème pour instancier un usercontrol

Bonsoir,
j'ai un problème au niveau de mon application wpf "GALERIE":
j'ai créé un usercontrol "galerie" où de même j'ai créé un usercontrol flow.
Dans le mainwindow j'ai voulu instancier un usercontrol galerie mais un erreur se signale:"impossible de créer une instance de galerie"
voilà mon code:
galerie.xaml
<UserControl x:Class="GALERIE.galerie"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Width="1000" Height="700" KeyDown="Window_KeyDown"
xmlns:flow="clr-namespace:GALERIE">

<Grid>
<Grid.Background>
<LinearGradientBrush StartPoint="0,0" EndPoint="0,1">
<LinearGradientBrush.GradientStops>
<GradientStop Color="Black" Offset="0"/>
<GradientStop Color="Red" Offset="1"/>
</LinearGradientBrush.GradientStops>
</LinearGradientBrush>


</Grid.Background>

<Grid>
<flow:FlowControl x:Name="flow" Margin="0">

</flow:FlowControl>
<Canvas>

<TextBlock x:Name="tblock" Canvas.Left="600" Canvas.Top="50" Height="30"


Foreground="Red"

FontFamily="Andalus"
FontSize="18"
FontStretch="UltraExpanded"
FontStyle="Italic"
FontWeight="UltraBold"

LineHeight="Auto"
Padding="5,10,5,10"
TextAlignment="Center"
TextWrapping="Wrap">
</TextBlock>

</Canvas>
</Grid>
</Grid>
</UserControl>


galerie.xaml.cs:
namespace GALERIE
{
/// <summary>
/// Logique d'interaction pour galerie.xaml
/// </summary>
public partial class galerie : UserControl
{
private void Window_KeyDown(object sender, KeyEventArgs e)
{
switch (e.Key)
{
case Key.Right:
flow.GoToNext();
tblock.Text = flow.get_element.get_imagename;
break;
case Key.Left:
flow.GoToPrevious();
tblock.Text = flow.get_element.get_imagename;
break;
case Key.Enter:
new RotatedWindow().ShowDialog();
break;


}
}

public galerie()
{
InitializeComponent();
MySqlConnection wConnexion = new MySqlConnection();
wConnexion.ConnectionString = "Data Source=127.0.0.1; Database=galerie_img;User id=root ";
// Connexion à la base de données
try
{
wConnexion.Open();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
return;
}

MySqlCommand wCommand = wConnexion.CreateCommand();

// Définition de la requête
wCommand.CommandText = "SELECT * FROM zones where id<10 ";

// Lecture des résultats
MySqlDataReader wReader = wCommand.ExecuteReader();
// string previousd="bizerte";

string image;
string iname;
// string name;
while (wReader.Read())
{
image =(string) wReader["image"];
//name = (string)wReader["Nom"];
//tblock.Text = name;
iname = (string)wReader["Nom"];




flow.Loadf(image,iname);
image = "";
iname = "";


}

tblock.Text = flow.get_element.get_imagename;

}




}

}

mainwindow.xaml
<Window x:Class="GALERIE.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" WindowState="Maximized"
xmlns:control="clr-namespace:GALERIE" >
<Grid>
<control:galerie x:Name="gal"/>
<Grid.Background>
<LinearGradientBrush StartPoint="0,0" EndPoint="0,1">
<LinearGradientBrush.GradientStops>
<GradientStop Color="Black" Offset="0"/>
<GradientStop Color="Red" Offset="1"/>
</LinearGradientBrush.GradientStops>
</LinearGradientBrush>

</Grid.Background>


</Grid>
</Window>


mainwindow.xaml.cs:

public partial class MainWindow : Window
{


public MainWindow()
{
InitializeComponent();


}
}