NodeChangingAction

NodeChangingAction enumeration

Specifies the type of node change.

public enum NodeChangingAction

Values

NameValueDescription
Insert0A node is being inserted in the tree.
Remove1A node is being removed from the tree.

Examples

Shows how to use a NodeChangingCallback to monitor changes to the document tree in real-time as we edit it.

public void NodeChangingCallback()
{
    Document doc = new Document();
    doc.NodeChangingCallback = new NodeChangingPrinter();

    DocumentBuilder builder = new DocumentBuilder(doc);
    builder.Writeln("Hello world!");
    builder.StartTable();
    builder.InsertCell();
    builder.Write("Cell 1");
    builder.InsertCell();
    builder.Write("Cell 2");
    builder.EndTable();

    builder.InsertImage(ImageDir + "Logo.jpg");            

    builder.CurrentParagraph.ParentNode.RemoveAllChildren();
}

/// <summary>
/// Prints every node insertion/removal as it takes place in the document.
/// </summary>
private class NodeChangingPrinter : INodeChangingCallback
{
    void INodeChangingCallback.NodeInserting(NodeChangingArgs args)
    {
        Assert.AreEqual(NodeChangingAction.Insert, args.Action);
        Assert.AreEqual(null, args.OldParent);
    }

    void INodeChangingCallback.NodeInserted(NodeChangingArgs args)
    {
        Assert.AreEqual(NodeChangingAction.Insert, args.Action);
        Assert.NotNull(args.NewParent);

        Console.WriteLine("Inserted node:");
        Console.WriteLine($"\tType:\t{args.Node.NodeType}");

        if (args.Node.GetText().Trim() != "")
        {
            Console.WriteLine($"\tText:\t\"{args.Node.GetText().Trim()}\"");
        }

        Console.WriteLine($"\tHash:\t{args.Node.GetHashCode()}");
        Console.WriteLine($"\tParent:\t{args.NewParent.NodeType} ({args.NewParent.GetHashCode()})");
    }

    void INodeChangingCallback.NodeRemoving(NodeChangingArgs args)
    {
        Assert.AreEqual(NodeChangingAction.Remove, args.Action);
    }

    void INodeChangingCallback.NodeRemoved(NodeChangingArgs args)
    {
        Assert.AreEqual(NodeChangingAction.Remove, args.Action);
        Assert.Null(args.NewParent);

        Console.WriteLine($"Removed node: {args.Node.NodeType} ({args.Node.GetHashCode()})");
    }
}

See Also