Let us first start with that we don't provide an example which demonstrates the mentioned approach in your post but you can achieve it by creating a custom implementation. You can take a look at the TableShape
online example which demonstrates how you can customize the diagram to look like a SQL diagram. Keep in mind that this example is MVVM based and we have created a custom class for the shape, container shape and the diagram itself. As for drag and drop an item from the ItemsControl you can take a look at the Drag and Drop Support
help article in our documentation which demonstrates how you can customize the drag/drop operations. Basically, when you drop an item you can create a model and added it in the graph source of the diagram.
Hope this information is helpful.
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