IContextNode::GetSubNodes method

Article
01/07/2021

Gets the direct child nodes of the IContextNode object.

Syntax

HRESULT GetSubNodes(
  [out] IContextNodes **ppSubContextNodes
);

Parameters

ppSubContextNodes [out]: A collection of the IContextNode objects that are direct child nodes of this IContextNode.

Return value

For a description of the return values, see Classes and Interfaces - Ink Analysis.

Remarks

Caution

To avoid a memory leak, call IUnknown::Release on *ppSubContextNodes when you no longer need to use the collection of subnodes.

This returns only the direct child nodes, not all of the descendant nodes.

Examples

This example shows a method, ExploreContextNode, that examines an IContextNode. The method does the following:

Gets the context node's type.
Examines specific properties of the node type by calling a helper method, if the context node is an unclassified ink, analysis hint, or custom recognizer node.
Examines each subnode by calling itself, if the node has subnodes.
Examines the stroke data for the node by calling a helper method, if the node is an ink leaf node.

HRESULT CMyClass::ExploreContextNode(
    IContextNode *pContextNode)
{
    // Check for certain types of context nodes.
    GUID ContextNodeType;
    HRESULT hr = pContextNode->GetType(&ContextNodeType);

    if (SUCCEEDED(hr))
    {
        if (IsEqualGUID(GUID_CNT_UNCLASSIFIEDINK, ContextNodeType))
        {
            // Call a helper method that explores unclassified ink nodes.
            hr = this->ExploreUnclassifiedInkNode(pContextNode);
        }
        else if (IsEqualGUID(GUID_CNT_ANALYSISHINT, ContextNodeType))
        {
            // Call a helper method that explores analysis hint nodes.
            hr = this->ExploreAnalysisHintNode(pContextNode);
        }
        else if (IsEqualGUID(GUID_CNT_CUSTOMRECOGNIZER, ContextNodeType))
        {
            // Call a helper method that explores custom recognizer nodes.
            hr = this->ExploreCustomRecognizerNode(pContextNode);
        }

        if (SUCCEEDED(hr))
        {
            // Check if this node is a branch or a leaf node.
            IContextNodes *pSubNodes = NULL;
            hr = pContextNode->GetSubNodes(&pSubNodes);

            if (SUCCEEDED(hr))
            {
                ULONG ulSubNodeCount;
                hr = pSubNodes->GetCount(&ulSubNodeCount);

                if (SUCCEEDED(hr))
                {
                    if (ulSubNodeCount > 0)
                    {
                        // This node has child nodes; explore each child node.
                        IContextNode *pSubNode = NULL;
                        for (ULONG index=0; index<ulSubNodeCount; index++)
                        {
                            hr = pSubNodes->GetContextNode(index, &pSubNode);

                            if (SUCCEEDED(hr))
                            {
                                // Recursive call to explore the child node of this
                                // context node.
                                hr = this->ExploreContextNode(pSubNode);
                            }

                            // Release this reference to the child context node.
                            if (pSubNode != NULL)
                            {
                                pSubNode->Release();
                                pSubNode = NULL;
                            }

                            if (FAILED(hr))
                            {
                                break;
                            }
                        }
                    }
                    else
                    {
                        // This is a leaf node. Check if it contains stroke data.
                        ULONG ulStrokeCount;
                        hr = pContextNode->GetStrokeCount(&ulStrokeCount);

                        if (SUCCEEDED(hr))
                        {
                            if (ulStrokeCount > 0)
                            {
                                // This node is an ink leaf node; call helper
                                // method that explores available stroke data.
                                hr = this->ExploreNodeStrokeData(pContextNode);
                            }
                        }
                    }
                }
            }

            // Release this reference to the subnodes collection.
            if (pSubNodes != NULL)
            {
                pSubNodes->Release();
                pSubNodes = NULL;
            }
        }
    }

    return hr;
}

Requirements

Requirement	Value
Minimum supported client	Windows XP Tablet PC Edition [desktop apps only]
Minimum supported server	None supported
Header	IACom.h (also requires IACom_i.c)
DLL	IACom.dll

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