Hi Paul,

Hosted controls are serialized using the WPF's XalmWriter and XamlReader classes. We'll check if anything can be done to avoid this.

Stoyan

Thanks for the suggestion.  Unfortunately for us this has no effect - the loading of the XML still generates the same messgae of an already registered name.  As our User Control inherrits from a base class, I added the above to the constructor of the base class too, but again without effect.

OK, having found that I had put one call in the wrong place.  We have now serialized and deserialized a very simple diagram with a couple of our user controls.  We are however still having some issues as in some instances a null reference exception is getting thrown:

   at MindFusion.Diagramming.Wpf.Diagram.LoadFromXml(XmlDocument document)
   at MindFusion.Diagramming.Wpf.Diagram.LoadFromString(String str)

I have compared two very similar diagrams using the same controls (one loads the other does not) and cannot seem to see any difference or areas that may create null references - do you have any tools that validate diagram xmls?  I'm happy to send you an XML that does not load but obviously you won't have any of our control DLLs to make proper use of it.


Many thanks


Paul

The call stack does not not make any reference to the mindfusion DLL (or the exception generally), but the try-catches are not capturing anything in my object constructors either - as soon as the last control is instanced, the code steps out of my user control code straight into the exception handler around the Diagram.LoadFromString call. My previous post mentioning the exception was truncated by one line (but the last line was my call). For completeness, full exception message as follows:

A first chance exception of type 'System.NullReferenceException' occurred in MindFusion.Diagramming.Wpf.dll
<MyMethodName>:Object reference not set to an instance of an object.
at MindFusion.Diagramming.Wpf.Diagram.LoadFromXml(XmlDocument document)
at MindFusion.Diagramming.Wpf.Diagram.LoadFromString(String str)
at <MyNamespace>.<my control>.<MyMethodName>(String pDiagramData, String pDiagramName) in <reference to line number in my method>

There would also appear to be an issue when controls on the diagram reference styles:

Cannot add content of type 'System.Windows.Style' to an object of type 'System.Windows.ResourceDictionary'.  Error at object 'btnStyle', Line 1 Position 583.

The following code can be used to reproduce this error;

*window xaml*
<Window x:Class="SerializationTest.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
       xmlns:local="clr-namespace:SerializationTest"
       xmlns:MF="clr-namespace:MindFusion.Diagramming.Wpf;assembly=MindFusion.Diagrammi
ng.Wpf"
    Title="Window1" Height="300" Width="300">
    <Grid>
       <MF:Diagram x:Name="oDiag"/>
    </Grid>
</Window>

*\Window code behind*
    public partial class Window1 : Window
    {
       public Window1()
       {
           InitializeComponent();

           TestControl testControl = new TestControl();
           testControl.Click += new RoutedEventHandler(testControl_Click);

           oDiag.Items.Add(testControl);

           Diagram.SetItemBounds(testControl, new Rect(0, 0, 50, 25));
       }

       void testControl_Click(object sender, RoutedEventArgs e)
       {
           Diagram newDiag = new Diagram();
           
           string diagXml =oDiag.SaveToString(SaveToStringFormat.Xml,true);

           //' exception thrown on this line
           newDiag.LoadFromString(diagXml);

       }
    }


*user control xaml*
<UserControl x:Class="SerializationTest.TestControl"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Height="Auto" Width="Auto">
    <UserControl.Resources>
       <Style x:Key="btnStyle" TargetType="{x:Type Button}">
           <Setter Property="Foreground" Value="White" />
       </Style>
    </UserControl.Resources>
    <Grid>
       <Button Style="{StaticResource btnStyle}" Height="25" Width="50" Content="Test button" x:Name="btnTest" />
    </Grid>
</UserControl>

*user control code behind
namespace SerializationTest
{
    /// <summary>
    /// Interaction logic for TestControl.xaml
    /// </summary>
    [Serializable]
    public partial class TestControl : UserControl
    {

       #region Click
           /// <summary>
           /// Routed event to pass out a click event to the main window
           /// </summary>
           public static readonly RoutedEvent ClickEvent = EventManager.RegisterRoutedEvent("Click",
                                                                                RoutingStrategy.Bubble,
                                                                                typeof(RoutedEvent),
                                                                                typeof(TestControl));

           public event RoutedEventHandler Click
           {
               add { AddHandler(ClickEvent, value); }
               remove { RemoveHandler(ClickEvent, value); }
           }

           void RaiseClickEvent()
           {
               RoutedEventArgs newEventArgs = new RoutedEventArgs(ClickEvent);
               RaiseEvent(newEventArgs);
           }
       #endregion

       public TestControl()
       {
           InitializeComponent();
           btnTest.Click += new RoutedEventHandler(btnTest_Click);
           NameScope.SetNameScope(this, new NameScope());
       }

       void btnTest_Click(object sender, RoutedEventArgs e)
       {
           RaiseClickEvent();
       }


    }
}

Is this solution going to be the same when using resource dictionaries?  I've managed to get the same behaviour in a control libraray and a resource dictionary file referenced in the following manor:

       <ResourceDictionary>
           <ResourceDictionary.MergedDictionaries>
               <ResourceDictionary Source="pack://application:,,,/cControls;Component/Dictionary1.xaml"/>
           </ResourceDictionary.MergedDictionaries>
       </ResourceDictionary>

We haven't tried this with resource dictionaries. What behavior did you got with them - still throwing the "Cannot add content" exception?