ASPxDiagram.NodeDataSource Property

public class Node {
    public string Key { get; set; }
    public string Text { get; set; }
    public string Type { get; set; }
    public Double Width { get; set; }
    public Double Height { get; set; }
}
public class Edge {
    public string Key { get; set; }
    public string Text { get; set; }
    public string FromKey { get; set; }
    public string ToKey { get; set; }
}

public static class DiagramDataProvider {
    const string
        NodeSessionKey = "Node",
        EdgeSessionKey = "Edge";

    static HttpSessionState Session { get { return HttpContext.Current.Session; } }
    public static object GetNodes() { return Nodes; }
    public static object GetEdges() { return Edges; }

    public static List<Node> Nodes {
        get {
            if (Session[NodeSessionKey] == null)
                Session[NodeSessionKey] = CreateNodes();
            return (List<Node>)Session[NodeSessionKey];
        }
    }
    public static List<Edge> Edges {
        get {
            if (Session[EdgeSessionKey] == null)
                Session[EdgeSessionKey] = CreateEdges();
            return (List<Edge>)Session[EdgeSessionKey];
        }
    }

    static List<Node> CreateNodes() {
        var result = new List<Node>();
        result.Add(new Node() { Key = "101", Text = "A new ticket", Type = "Terminator", Width = 1.25, Height = 0.5 });
        result.Add(new Node() { Key = "102", Text = "Analyze the issue", Type = "Process", Width = 1.5, Height = 0.5 });
        result.Add(new Node() { Key = "103", Text = "Do we have all \n information to \n work with?", Type = "Decision", Width = 1.75, Height = 1 });
        result.Add(new Node() { Key = "104", Text = "Request additional information or clarify the scenario", Type = "Process", Width = 1.5, Height = 0.5 });
        result.Add(new Node() { Key = "105", Text = "Process the ticket", Type = "Process", Width = 1.5, Height = 0.5 });
        result.Add(new Node() { Key = "106", Text = "Work with the \n R & D team", Type = "Process", Width = 1.5, Height = 0.5 });
        result.Add(new Node() { Key = "107", Text = "Answered", Type = "Terminator", Width = 1.25, Height = 0.5 });
        result.Add(new Node() { Key = "108", Text = "Prepare an example in Code Central", Type = "Process", Width = 1.5, Height = 0.5 });
        result.Add(new Node() { Key = "109", Text = "Update the documentation", Type = "Process", Width = 1.5, Height = 0.5 });
        return result;
    }
    static List<Edge> CreateEdges() {
        var result = new List<Edge>();
        result.Add(new Edge() { Key = "201", FromKey = "101", ToKey = "102" });
        result.Add(new Edge() { Key = "202", FromKey = "102", ToKey = "103" });
        result.Add(new Edge() { Key = "203", FromKey = "103", ToKey = "104", Text = "No" });
        result.Add(new Edge() { Key = "204", FromKey = "104", ToKey = "102" });
        result.Add(new Edge() { Key = "205", FromKey = "103", ToKey = "105", Text = "Yes" });
        result.Add(new Edge() { Key = "206", FromKey = "105", ToKey = "106", Text = "Need developer assistance?" });
        result.Add(new Edge() { Key = "207", FromKey = "106", ToKey = "107" });
        result.Add(new Edge() { Key = "208", FromKey = "105", ToKey = "107" });
        result.Add(new Edge() { Key = "209", FromKey = "107", ToKey = "108" });
        result.Add(new Edge() { Key = "209", FromKey = "107", ToKey = "109" });
        return result;
    }
}

protected void Page_Init(object sender, EventArgs e) {
    ASPxDiagram1.NodeDataSource = DiagramDataProvider.Nodes;
    ASPxDiagram1.EdgeDataSource = DiagramDataProvider.Edges;
    ASPxDiagram1.DataBind();
}