How to pass content of edited node as parameter

[hokushin]

Hello,

I am developing Silverlight application using MVVM design pattern and Telerik TreeView control. I want to pass the content of the Edited Node to ViewModel class. I am trying to do it like below. It doesn't work though. Please advise.

<telerikNavigation:RadTreeView Grid.Row="1" x:Name="tree" IsEditable="True" BorderThickness="1" BorderBrush="#FF9ABFE5" Margin="3">

            <i:Interaction.Triggers>
                <i:EventTrigger EventName="Edited">
                    <i:InvokeCommandAction Command="{Binding ItemEditedCommand}" CommandParameter="{Binding CurrentTerritory, Mode=OneWay" />
                </i:EventTrigger>
            </i:Interaction.Triggers>

            <telerikNavigation:RadTreeView.ItemTemplate>
                <telerik:HierarchicalDataTemplate ItemsSource="{Binding Childs}"  >
                    <StackPanel Orientation="Horizontal">
                        <TextBlock Text="{Binding Name, Mode=TwoWay}" HorizontalAlignment="Stretch" VerticalAlignment="Center"/>
                    </StackPanel>
                </telerik:HierarchicalDataTemplate>
            </telerikNavigation:RadTreeView.ItemTemplate>
            <telerikNavigation:RadTreeView.ItemContainerStyle>
                <Style TargetType="telerikNavigation:RadTreeViewItem">
                    <Setter Property="HorizontalAlignment" Value="Stretch"/>
                    <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
                    <Setter Property="IsExpanded" Value="True" />
                </Style>
            </telerikNavigation:RadTreeView.ItemContainerStyle>
            <telerikNavigation:RadTreeView.ItemEditTemplate>
                <DataTemplate>
                    <TextBox Text="{Binding Name, Mode=TwoWay}" >
                    </TextBox>
                </DataTemplate>
            </telerikNavigation:RadTreeView.ItemEditTemplate>
        </telerikNavigation:RadTreeView>



public TerritoryListVM(IUIMessageBox uiMessageBox, AsyncCaller asyncCaller)
        {
            ItemEditedCommand = new DelegateCommand((a) => { this.ItemEditedCommandAction(a); }, (p) => { return true; });

            LoadData();
        }

public const string PnCurrentTerritory = "CurrentTerritory";
        private TerritoryDB _currentTerritory;
        public virtual TerritoryDB CurrentTerritory
        {
            get
            {
                return _currentTerritory;
            }
            set
            {
                if (_currentTerritory != value)
                {
                    _currentTerritory = value;
                    OnPropertyChanged(PnCurrentTerritory);
                }
            }
        }

public DelegateCommand ItemEditedCommand { get; set; }

        private void ItemEditedCommandAction(object param)
        {
            string filter = param as string;
.......................................
         }

[hokushin]

I've figured out the problem with GalaSoft.mvvmlight. The question is how can I persist the node in edit mode while performing node validation via WCF service

[Petar Mladenov]

Hello Hokushin,

 Could you please elaborate more on your last question? This way we would be better able to advice you.

Regards,
Petar Mladenov
the Telerik team

[hokushin]

Actually, I found the way to persist the node in edit node. Please see below how I did it

private GalaSoft.MvvmLight.Command.RelayCommand<RadTreeViewItemEditedEventArgs> myCommand;

        public GalaSoft.MvvmLight.Command.RelayCommand<RadTreeViewItemEditedEventArgs> MyCommand
        {
            get
            {
                return myCommand;
            }
        }

private void myCommand_Execute(RadTreeViewItemEditedEventArgs e)
        {
            RadTreeViewItem clickedItem = e.OriginalSource as RadTreeViewItem;
            _asyncCaller.Call(c => _context.BeginGetDublicateCountForTerritory(CurrentTerritory, c, null), _context.EndGetDublicateCountForTerritory, cnt =>
            {
                if (cnt)
                {
                    // node in edit mode
                    (e.Source as RadTreeViewItem).IsInEditMode = true;
                    (e.Source as RadTreeViewItem).Focus();
                    (e.Source as RadTreeViewItem).Background = new SolidColorBrush(Colors.Red);
                    //_uiMessageBox.Show("Данная территория уже уже добавлена в базу данных.");
                }
                else
                {
                    // 5.5.2012 сохраняем изменения в базу данных
                    (e.Source as RadTreeViewItem).IsInEditMode = false;
                    _asyncCaller.Call(c => _context.BeginModifyTerritories(_collectionInspector.GetDiff(), c, null), _context.EndModifyTerritories, null);
                }

            });
        }

Now I want to apply some validation style to the node (instead of MessageBox) I've implemented INotifyDataErrorInfo interface for the node but it doesn't work:

<telerikNavigation:RadTreeView.ItemEditTemplate>
                <DataTemplate>
                    <TextBox Text="{Binding Name, Mode=TwoWay, ValidatesOnExceptions=True,ValidatesOnNotifyDataErrors=True}" />             
                </DataTemplate>
            </telerikNavigation:RadTreeView.ItemEditTemplate>

So I am thinking of looping through the control tree and then using ControlValidationHelper helper class: http://stackoverflow.com/questions/4158503/set-validation-message-on-control-manually. But it's time consuming. So I wish the RadTreeView had some built in validation stuff. I've drilled down through the forum but failed to find what I needed.

[hokushin]

Hi Petar,
How are you doing? I hope that you are well.
So, I've created a couple of methods below. Everything works fine with DataForm:

private void ValidateTerritory()
{
   if (string.IsNullOrEmpty(this.TerritoryDB.Name))
   {
      Extensions.ValidateField<TextBox>(this.addTerritoryDataForm, "Name", ErrorResources.RequiredField);
   }
   else
   {
      Extensions.ClearField<TextBox>(this.addTerritoryDataForm, "ValidateName");
   }

How can I access the item in the ItemEditTemplate on the RadTreeView ?

<telerikNavigation:RadTreeView.ItemEditTemplate>
                <DataTemplate>
                    <TextBox Text="{Binding ValidatedName, Mode=TwoWay, ValidatesOnExceptions=True, NotifyOnValidationError=True}" />
                </DataTemplate>
            </telerikNavigation:RadTreeView.ItemEditTemplate>

I\ve tried the approach below etc but it didn't make the trick:

FrameworkElement element = e.OriginalSource as FrameworkElement;
Extensions.ValidateField<RadTreeViewItem>(element, "ValidateName", ErrorResources.RequiredField);

Your comments and suggestions would be greatly appreciated.

public static class Extensions
    {
        public static T FindChild<T>(DependencyObject parent, string childName)
   where T : DependencyObject
        {
            // Confirm parent and childName are valid.
            if (parent == null) return null;

            T foundChild = null;

            int childrenCount = VisualTreeHelper.GetChildrenCount(parent);
            for (int i = 0; i < childrenCount; i++)
            {
                var child = VisualTreeHelper.GetChild(parent, i);
                // If the child is not of the request child type child
                T childType = child as T;
                if (childType == null)
                {
                    // recursively drill down the tree
                    foundChild = FindChild<T>(child, childName);

                    // If the child is found, break so we do not overwrite the found child.
                    if (foundChild != null) break;
                }
                else if (!string.IsNullOrEmpty(childName))
                {
                    var frameworkElement = child as FrameworkElement;
                    // If the child's name is set for search
                    if (frameworkElement != null && frameworkElement.Name == childName)
                    {
                        // if the child's name is of the request name
                        foundChild = (T)child;
                        break;
                    }
                }
                else
                {
                    // child element found.
                    foundChild = (T)child;
                    break;
                }
            }

            return foundChild;
        }


        // http://stackoverflow.com/questions/636383/wpf-ways-to-find-controls
        public static void ValidateField<T>(DependencyObject dobj, string strField, string strErrorMessage)
            where T : DependencyObject
        {
            object foundControl = FindChild<T>(dobj, strField);

            if (foundControl is T)
            {
                // Following executed if Text element was found.

                var controlToValidate = foundControl as FrameworkElement;

                var helper = new ControlValidationHelper() { Message = strErrorMessage };
                controlToValidate.SetBinding(Control.TagProperty, new Binding("ValidationError")
                {
                    Mode = BindingMode.TwoWay,
                    NotifyOnValidationError = true,
                    ValidatesOnDataErrors = true,
                    UpdateSourceTrigger = UpdateSourceTrigger.Explicit,
                    Source = helper
                });
                controlToValidate.GetBindingExpression(Control.TagProperty).UpdateSource();
            }
        }

        public static void ClearField<T>(DependencyObject dobj, string strFieldName)
            where T : DependencyObject
        {
            object foundControl = FindChild<T>(dobj, strFieldName);

            if (foundControl is T)
            {
                // Following executed if Text element was found.
                var controlToClear = foundControl as FrameworkElement;

                BindingExpression b = controlToClear.GetBindingExpression(Control.TagProperty);
                if (b != null)
                {
                    ((ControlValidationHelper)b.DataItem).Message = null;
                    b.UpdateSource();
                }
            }
        } 

    }

[Petar Mladenov]

Hi V A,

 As I managed to understand, you need to access in code behind the TextBox from the ItemEditTemplate.
If so, have you tried the Telerik's Extension method ChildrenOfType<> from Telerik.Windows.Controls namespace ?

All the best,
Petar Mladenov
the Telerik team