Проблема с биндом после евента

У меня проблема с биндом текста второго TextBox_SeriallBuffer после ивента первого TextBox_Scan. После ивента TextBox_Scan не остается текст в TextBox_SeriallBuffer

XAML TextBox_SerialBuffer :

<TextBox x:Name ="TextBox_SerialBuffer" 
    TextWrapping="Wrap"
    TextAlignment="Justify"
    Margin="1,1,1,1" 
    Background="{DynamicResource {x:Static SystemColors.HighlightTextBrushKey}}"
    Padding="1"
    FontSize="13"
    FontFamily="Consolas"
    Text="{Binding Path=Text, 
    ElementName=TextBox_Scan, 
    Mode=TwoWay,
    UpdateSourceTrigger=PropertyChanged}" />
                         

XAML TextBox_Scan :

<TextBox x:Name="TextBox_Scan" 
    HorizontalAlignment="Left" 
    Margin="173,165,0,0" 
    TextWrapping="NoWrap" 
    VerticalAlignment="Top"
    Width="302" 
    FontSize="13"
    KeyDown="TextBox_Scan_KeyDown" 
    FontFamily="Consolas"
    FontWeight="Normal"/>

Ивент KeyDown="TextBox_Scan_KeyDown"

C# :

   private void TextBox_Scan_KeyDown(object sender, System.Windows.Input.KeyEventArgs e)
    {
        string Inputed_value = TextBox_Scan.Text;

        if (Keyboard.IsKeyDown(Key.Enter))
        {
            if (Inputed_value.Length == 0)
            {
                MessageBox.Show("You didn't scan anything", nameApp, MessageBoxButton.OK, MessageBoxImage.Information);
                logger.Info(nameWin + Fail + "You didn't scan anything");
                return;
            }
            else
            {
                Count_value++;
                logger.Info(nameWin + Pass + "Entered value : " + Count_value + "." + Inputed_value);
                TextBox_Scan.Clear();
                return;
            }

        }
    }

Помогите пожалуйста решить проблему.