>I created my first simple winforms host xaml application containing one simple page.
>
>Trying to run it causes error
>
>System.Windows.Markup.XamlParseException was unhandled
>Message: Cannot create instance of 'Page1' defined in assembly 'WPFHost,
>Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'. Exception has been
>thrown by the target of an invocation. Error in markup file 'Page1.xaml'
>Line 1 Position 7.
>
>There is no any other inforamtion available about this error.
>How to fix?
>
>Andrus.
>
>Page1.xaml:
>

><Page x:Class="WPFHost.Page1"
>    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
>    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
>    Title="Page1">
>    <Grid>
>        <StackPanel Margin="0,0,0,0" Name="stackPanel"
>           HorizontalAlignment="Left" VerticalAlignment="Top" />
>    </Grid>
></Page>
>
>
>
>
>page1.xaml.cs:
>
>
>using System.Windows.Controls;
>using System.Windows.Forms.Integration;
>using MyApp.UI;
>
>namespace WPFHost
>{
>    /// <summary>
>    /// Interaction logic for Page1.xaml
>    /// </summary>
>    public partial class Page1 : Page
>    {
>        private readonly MainForm mainForm = new MainForm();
>
>        public Page1()
>        {
>            InitializeComponent();
>
>            //Create a Windows Forms Host to host a form
>            WindowsFormsHost windowsFormsHost = new WindowsFormsHost();
>
>            stackPanel.Width = mainForm.Width;
>            stackPanel.Height = mainForm.Height;
>            windowsFormsHost.Width = mainForm.Width;
>            windowsFormsHost.Height = mainForm.Height;
>
>            mainForm.TopLevel = false;
>
>            windowsFormsHost.Child = mainForm;
>
>            stackPanel.Children.Add(windowsFormsHost);
>        }
>    }
>}
>

Hi,

I think the problem is probably in the c# constructor code for Page1 but it's not possible to say where since you don't show code for WindowsFormsHost or mainForm (if you chop out all of the constructor code except InitializeComponent it compiles OK)
Regards,
Viv