Binding Warning When Expand Nested Property - FieldIndicatorVisibility

[Joel]

verson: 2014.3.1021.40

xaml:

<telerik:RadPropertyGrid x:Name="grdTestProperty"
                          Item="{Binding TestProperty, Mode=OneWay}" SearchBoxVisibility="Collapsed" SearchInNestedProperties="False"
                          FieldIndicatorVisibility="Visible"
                          AutoGeneratePropertyDefinitions="True"
                          NestedPropertiesVisibility="Visible"
                          LabelColumnWidth="110" RenderMode="Flat"
                          AutoGeneratingPropertyDefinition="grdTestProperty_AutoGeneratingPropertyDefinition" />

 

Code Behind:

private void grdTestProperty_AutoGeneratingPropertyDefinition(object sender, Telerik.Windows.Controls.Data.PropertyGrid.AutoGeneratingPropertyDefinitionEventArgs e)
        {
            // http://www.telerik.com/forums/expand-nested-properties-at-startup
            // Encounter this warning when set IsExpanded = true:
            e.PropertyDefinition.IsExpanded = true;
        }

 

Nested Property:

[DataMember()]
[Browsable(true)]
[Display(Order = 5, GroupName = "PropGroup_Electrical", Name = "PropName_ElecItem", Description = "PropDesc_ElecItem", ResourceType = typeof(UIStringTable))]
public ElectricalTestItem ElecItem
{
    get { return m_ElecItem; }
    private set
    {
        m_ElecItem = value;
        NotifyOfPropertyChange(() => ElecItem);
    }
}

 

Warning:

System.Windows.Data Error: 4 : Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='Telerik.Windows.Controls.RadPropertyGrid', AncestorLevel='1''. BindingExpression:Path=FieldIndicatorVisibility; DataItem=null; target element is 'Grid' (Name='FieldIndicator'); target property is 'Visibility' (type 'Visibility')

[Joel]

view model for the xaml (which contains the property grid):

public class TestPropertyViewModel : PaneViewModel, IHandle<TestListEntity>
{
        public TestItem TestProperty
        {
            // Bind to property grid.
            get { return m_TestItem; }
            set
            {
                m_TestItem = value;
                NotifyOfPropertyChange(() => TestProperty);
            }
        }
}

TestItem class which contains the Nested Property ElectricalTestItem

public class TestItem : PropertyChangedBase
{
    [DataMember()]
    [Browsable(true)]
    [Display(Order = 5, GroupName = "PropGroup_Electrical", Name = "PropName_ElecItem", Description = "PropDesc_ElecItem", ResourceType = typeof(UIStringTable))]
    public ElectricalTestItem ElecItem
    {
        get { return m_ElecItem; }
        private set
        {
            m_ElecItem = value;
            NotifyOfPropertyChange(() => ElecItem);
        }
    }
}

 

 I would like to expand the nested property when the property grid's Item has changed. 

 Why expanding the nested property with the code behind generates the warning - even though the nested property did expand in the view? Have i missed out anything?

p/s:  Expanding the nested property by clicking the "+" sign is OK. 

[Stefan]

Hi Joel,

As I am not able to reproduce such warning with the version you are using, I am attaching a sample project. Would it be possible for you to modify in a way that reproduces the error, open a new support thicket and attach it in it, so I can debug it on my side and guide you accordingly?

Best Regards,
Stefan X1
Telerik

[Joel]

Hi Stefan,

 I have submitted a support ticket ID: 936977

 Instead of assigning the property item at Load, I have created a button to assign the property when it is clicked.

void btnShow_Click(object sender, RoutedEventArgs e)
{
    this.propertyGrid.Item = Club.GetClubs().ElementAt(0);
}

[Stefan]

Hi Joel,

Thank you for the provided project.

This error is harmless and is handled internally by the Framework. Please check the Resolving harmless binding errors in WPF blog post, as well the System.Windows.Data Error: 4 : Cannot find source for binding with reference in WPF Tree View / Tree View Item forum thread for further reference.

Best Regards,
Stefan X1
Telerik