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ContextNode Class

Represents a node in a tree of objects that are created as part of ink analysis.

Namespace:  System.Windows.Ink
Assembly:  IAWinFX (in IAWinFX.dll)

public class ContextNode

After an InkAnalyzer performs an ink analysis, it presents the results as a tree of ContextNode objects. The [T:System.Windows.Ink.RootNode is located at the top of the tree]; the tree presents smaller and smaller collections of strokes further down the tree. These nodes can be groups of words (such as paragraphs or lines), analyzed ink (such as words or drawings), or a variety of other types. (See the ContextNodeType class for a full list.)

You can manually add nodes, such as AnalysisHintNode, ImageNode and TextWordNode objects, to the InkAnalyzer.

In cases of corrupt input, this method throws a ArgumentException exception.

This example takes an InkAnalyzer named theInkAnalyzer, and uses its ContextNode tree to fill a [System.Windows.Controls.TreeView] named theTreeView. When a node belonging to a tree view is selected, its associated strokes are set to appear in red. The [System.Windows.FrameworkElement.Tag] property is used to map between tree nodes and the context nodes that they represent.

private void BuildTree()
{
    // Remove the old nodes from the TreeView and add the current results. 
    this.theResultsTreeView.Items.Clear();

    TreeViewItem rootNode = new TreeViewItem();
    rootNode.Tag = this.theInkAnalyzer.RootNode;
    rootNode.Header = theInkAnalyzer.RootNode.ToString();

    this.theResultsTreeView.Items.Add(rootNode);

    WalkTree(this.theInkAnalyzer.RootNode, rootNode);

}

private static void WalkTree(ContextNode parentContextNode, TreeViewItem parentTreeNode)
{
    // Expand the current TreeViewItem.
    parentTreeNode.IsExpanded = true;

    foreach (ContextNode theContextSubnode
        in parentContextNode.SubNodes)
    {
        TreeViewItem newTreeNode = new TreeViewItem();
        newTreeNode.Header = theContextSubnode.ToString();

        if (theContextSubnode is InkWordNode)
        {
            newTreeNode.Header += ": " +
                ((InkWordNode)theContextSubnode).GetRecognizedString();
        }
        else if (theContextSubnode is InkDrawingNode)
        {
            newTreeNode.Header += ": " +
                ((InkDrawingNode)theContextSubnode).GetShapeName();
        }

        // If the context node is confirmed, add a note to the 
        // tree view item. 
        if (theContextSubnode.IsConfirmed(ConfirmationType.NodeTypeAndProperties))
        {
            newTreeNode.Header += " Confirmed.";
        }

        // Add the context node as a tag of the tree view item and 
        // add the new tree view item to the parent node.
        newTreeNode.Tag = theContextSubnode;
        parentTreeNode.Items.Add(newTreeNode);

        WalkTree(theContextSubnode, newTreeNode);
    }
}


void theResultsTreeView_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
    TreeViewItem selectedTreeViewItem = e.NewValue as TreeViewItem;

    if (selectedTreeViewItem == null)
    {
        return;
    }

    // Get the context node
    ContextNode selectedNode = (ContextNode)selectedTreeViewItem.Tag;

    MarkNodeAsRed(selectedNode);

    timeStampLabel.Content = "";

    // Show selected results 
    if (selectedNode != null)
    {
        if (selectedNode.Type == ContextNodeType.WritingRegion)
        {
            WritingRegionNode writingRegion = (WritingRegionNode)selectedNode;
            selectedResultsTextBox.Text = writingRegion.GetRecognizedString();
        }
        else if (selectedNode.Type == ContextNodeType.Paragraph)
        {
            ParagraphNode paragraph = (ParagraphNode)selectedNode;
            selectedResultsTextBox.Text = paragraph.GetRecognizedString();
        }
        else if (selectedNode.Type == ContextNodeType.Line)
        {
            LineNode line = (LineNode)selectedNode;
            selectedResultsTextBox.Text = line.GetRecognizedString();
        }
        else if (selectedNode.Type == ContextNodeType.InkWord)
        {
            InkWordNode inkWord = (InkWordNode)selectedNode;
            ContextNode parentNode = inkWord.ParentNode;
            if (parentNode is LineNode)
            {
                LineNode parentLine = (LineNode)parentNode;
                // Put parent line's recognized string into the text box
                selectedResultsTextBox.Text = parentLine.GetRecognizedString();

                // Select the text that corresponds to the ink word
                ContextNodeCollection subNodes = new ContextNodeCollection(theInkAnalyzer);
                subNodes.Add(inkWord);
                int start;
                int length;
                parentLine.GetTextRangeFromNodes(subNodes, out start, out length);
                if (start >= 0 && length > 0)
                {
                    selectedResultsTextBox.Select(start, length);
                }
            }
        }
        else if (selectedNode.Type == ContextNodeType.InkDrawing)
        {
            InkDrawingNode drawingNode = (InkDrawingNode)selectedNode;
            selectedResultsTextBox.Text = drawingNode.GetShapeName();
        }
        else if (selectedNode.Type == ContextNodeType.InkBullet)
        {
            InkBulletNode bulletNode = (InkBulletNode)selectedNode;
            selectedResultsTextBox.Text = bulletNode.GetRecognizedString();
        }
        else if (selectedNode.Type == ContextNodeType.CustomRecognizer)
        {
            CustomRecognizerNode customRecognizer = (CustomRecognizerNode)selectedNode;
            selectedResultsTextBox.Text = customRecognizer.GetRecognizedString();
        }
        else if (selectedNode.Type == ContextNodeType.Object)
        {
            ObjectNode selectedObject = (ObjectNode)selectedNode;
            selectedResultsTextBox.Text = selectedObject.GetRecognizedString();
        }
        else
        {
            selectedResultsTextBox.Text = "";
        }

        if (selectedNode is InkWordNode)
        {
            InkWordNode inkWord = (InkWordNode)selectedNode;

            // Show the time stamp 
            if (inkWord.ContainsPropertyData(this.timeStampGuid))
            {
                DateTime timeStamp =
                    (DateTime)inkWord.GetPropertyData(this.timeStampGuid);
                timeStampLabel.Content = timeStamp.ToShortTimeString();
            }

            // Snippet to demonstrate GetPropertyDataIds
            Guid[] propertyDataIds = inkWord.GetPropertyDataIds();
            // Snippets to demonstrate loading and saving
            byte[] data = inkWord.SavePropertiesData();
            if (!inkWord.LoadPropertiesData(data))
                MessageBox.Show("Cannot load property data");
        }

    }
    PopulateLinksList(selectedNode);
    this.currentNode = selectedNode;
}

private void PopulateLinksList(ContextNode selectedNode)
{
    linksListBox.Items.Clear();
    if (selectedNode == null)
    {
        return;
    }

    foreach (ContextLink link in selectedNode.Links)
    {
        linksListBox.Items.Add(link.SourceNode.ToString() + ", " +
                                    link.DestinationNode.ToString() + ": " +
                                    link.LinkDirection.ToString());
    }
}

private void MarkNodeAsRed(ContextNode selectedNode)
{
    // Set all node strokes to black, but this one to red 
    foreach (Stroke stroke in this.theInkCanvas.Strokes)
    {
        if (selectedNode != null &&
            selectedNode.Strokes.Contains(stroke))
            stroke.DrawingAttributes.Color = Colors.Red;
        else
            stroke.DrawingAttributes.Color = 
                this.theInkCanvas.DefaultDrawingAttributes.Color;
    }
}

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.0

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