Hi,

If the four object types from the page linked below are all symbols used in such diagrams, it should be possible to create them with the following DiagramItem types:

http://www.agilemodeling.com/artifacts/dataFlowDiagram.htm

1. A rectangular ShapeNode.
2. A ShapeNode with Shape set to RoundRect, or a TableNode with Style set to RoundRect.
3. DiagramLinks.
4. You might create a custom Shape for such open-ended rectangles, with an empty outline and only decoration elements added for drawing the three existing sides of the rectangle. Another option is to set CustomDraw = Full, handle DrawNode and call e.Graphics.DrawLine to render the three sides.

Also it's not hard to derive from DiagramNode and create the three node types you need with properties and drawing code specific to each type.

I hope that helps,
Stoyan