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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)

Syntax

'Declaration
Public Class ContextNode
'Usage
Dim instance As ContextNode
public class ContextNode
public ref class ContextNode
public class ContextNode

Remarks

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.

Examples

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 Sub BuildTree() 
    ' Remove the old nodes from the TreeView and add the current results. 
    Me.theResultsTreeView.Items.Clear()

    Dim rootNode As New TreeViewItem()
    rootNode.Tag = Me.theInkAnalyzer.RootNode
    rootNode.Header = theInkAnalyzer.RootNode.ToString()

    Me.theResultsTreeView.Items.Add(rootNode)

    WalkTree(Me.theInkAnalyzer.RootNode, rootNode)

End Sub 'BuildTree


Private Shared Sub WalkTree(ByVal parentContextNode As ContextNode, ByVal parentTreeNode As TreeViewItem) 

    parentTreeNode.IsExpanded = True 

    For Each theContextSubnode As ContextNode In parentContextNode.SubNodes
        Dim newTreeNode As New TreeViewItem()
        newTreeNode.Header = theContextSubnode.ToString()

        If TypeOf theContextSubnode Is InkWordNode Then
            newTreeNode.Header += ": " + CType(theContextSubnode, InkWordNode).GetRecognizedString()
        ElseIf TypeOf theContextSubnode Is InkDrawingNode Then
            newTreeNode.Header += ": " + CType(theContextSubnode, InkDrawingNode).GetShapeName()
        End If 

        ' If the context node is confirmed, add a note to the 
        ' tree view item. 
        If (theContextSubnode.IsConfirmed(ConfirmationType.NodeTypeAndProperties)) Then

            newTreeNode.Header += " Confirmed." 
        End If 


        ' 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)
    Next theContextSubnode

End Sub 'WalkTree

Sub theResultsTreeView_SelectedItemChanged(ByVal sender As Object, _
                                           ByVal e As RoutedPropertyChangedEventArgs(Of Object))
    Dim selectedTreeViewItem As TreeViewItem = e.NewValue '

    If selectedTreeViewItem Is Nothing Then 
        Return 
    End If 

    ' Get the context node 
    Dim selectedNode As ContextNode = CType(selectedTreeViewItem.Tag, ContextNode)

    MarkNodeAsRed(selectedNode)

    timeStampLabel.Content = "" 

    ' Show selected results 
    If Not (selectedNode Is Nothing) Then 
        If selectedNode.Type = ContextNodeType.WritingRegion Then 
            Dim writingRegion As WritingRegionNode = CType(selectedNode, WritingRegionNode)
            selectedResultsTextBox.Text = writingRegion.GetRecognizedString()
        ElseIf selectedNode.Type = ContextNodeType.Paragraph Then 
            Dim paragraph As ParagraphNode = CType(selectedNode, ParagraphNode)
            selectedResultsTextBox.Text = paragraph.GetRecognizedString()
        ElseIf selectedNode.Type = ContextNodeType.Line Then 
            Dim line As LineNode = CType(selectedNode, LineNode)
            selectedResultsTextBox.Text = line.GetRecognizedString()
        ElseIf selectedNode.Type = ContextNodeType.InkWord Then 
            Dim inkWord As InkWordNode = CType(selectedNode, InkWordNode)
            Dim parentNode As ContextNode = inkWord.ParentNode
            If TypeOf parentNode Is LineNode Then 
                Dim parentLine As LineNode = CType(parentNode, LineNode)
                ' Put parent line's recognized string into the text box
                selectedResultsTextBox.Text = parentLine.GetRecognizedString()

                ' Select the text that corresponds to the ink word 
                Dim subNodes As New ContextNodeCollection(theInkAnalyzer)
                subNodes.Add(inkWord)
                Dim start As Integer 
                Dim length As Integer
                parentLine.GetTextRangeFromNodes(subNodes, start, length)
                If start >= 0 AndAlso length > 0 Then
                    selectedResultsTextBox.Select(start, length)
                End If 
            End If 
        ElseIf selectedNode.Type = ContextNodeType.InkDrawing Then 
            Dim drawingNode As InkDrawingNode = CType(selectedNode, InkDrawingNode)
            selectedResultsTextBox.Text = drawingNode.GetShapeName()
        ElseIf selectedNode.Type = ContextNodeType.InkBullet Then 
            Dim bulletNode As InkBulletNode = CType(selectedNode, InkBulletNode)
            selectedResultsTextBox.Text = bulletNode.GetRecognizedString()
        ElseIf selectedNode.Type = ContextNodeType.CustomRecognizer Then 
            Dim customRecognizer As CustomRecognizerNode = CType(selectedNode, CustomRecognizerNode)
            selectedResultsTextBox.Text = customRecognizer.GetRecognizedString()
        ElseIf selectedNode.Type = ContextNodeType.Object Then 
            Dim selectedObject As ObjectNode = CType(selectedNode, ObjectNode)
            selectedResultsTextBox.Text = selectedObject.GetRecognizedString()
        Else
            selectedResultsTextBox.Text = "" 
        End If 
        If TypeOf selectedNode Is InkWordNode Then 
            Dim inkWord As InkWordNode = CType(selectedNode, InkWordNode)

            ' Show the time stamp 
            If inkWord.ContainsPropertyData(Me.timeStampGuid) Then 
                Dim timeStamp As DateTime = CType(inkWord.GetPropertyData(Me.timeStampGuid), DateTime)
                timeStampLabel.Content = timeStamp.ToShortTimeString()
            End If 
            ' Snippet to demonstrate GetPropertyDataIds 
            Dim propertyDataIds As Guid() = inkWord.GetPropertyDataIds()
            ' Snippets to demonstrate loading and saving 
            Dim data As Byte() = inkWord.SavePropertiesData()
            If Not inkWord.LoadPropertiesData(data) Then
                MessageBox.Show("Cannot load property data")
            End If 
        End If 
    End If
    PopulateLinksList(selectedNode)
    Me.currentNode = selectedNode
End Sub 

Private Sub PopulateLinksList(ByVal selectedNode As ContextNode)

    linksListBox.Items.Clear()

    If selectedNode Is Nothing Then 
        Return 
    End If 

    Dim link As ContextLink
    For Each link In selectedNode.Links
        linksListBox.Items.Add(link.SourceNode.ToString() + ", " & _
                                    link.DestinationNode.ToString() & ": " & _
                                    link.LinkDirection.ToString())
    Next 
End Sub 

Sub MarkNodeAsRed(ByVal selectedNode As ContextNode)
    ' Set all node strokes to black, but this one to red 
    Dim stroke As Stroke
    For Each stroke In Me.theInkCanvas.Strokes
        If Not (selectedNode Is Nothing) AndAlso selectedNode.Strokes.Contains(stroke) Then
            stroke.DrawingAttributes.Color = Colors.Red
        Else
            stroke.DrawingAttributes.Color = Me.theInkCanvas.DefaultDrawingAttributes.Color
        End If 
    Next stroke

End Sub 'theResultsTreeView_SelectedItemChanged 
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;
    }
}

Inheritance Hierarchy

System.Object
  System.Windows.Ink.ContextNode
    System.Windows.Ink.AnalysisHintNode
    System.Windows.Ink.CustomRecognizerNode
    System.Windows.Ink.ImageNode
    System.Windows.Ink.InkBulletNode
    System.Windows.Ink.InkDrawingNode
    System.Windows.Ink.InkWordNode
    System.Windows.Ink.LineNode
    System.Windows.Ink.ObjectNode
    System.Windows.Ink.ParagraphNode
    System.Windows.Ink.RootNode
    System.Windows.Ink.TextWordNode
    System.Windows.Ink.UnclassifiedInkNode
    System.Windows.Ink.WritingRegionNode

Thread Safety

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

Platforms

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.

Version Information

.NET Framework

Supported in: 3.0

See Also

Reference

ContextNode Members

System.Windows.Ink Namespace

InkAnalyzer.Analyze

InkAnalyzer.RootNode

System.Windows.Ink.ContextNodeType