How to prevent the diagram area from scrolling down while adding a new element in WinForms Diagram?

In our WinForms Diagram control, you can prevent the diagram area from scrolling down while adding a new element by overriding the GetBoundingRect method in the custom DiagramController class. By updating the bounds of the model, you can maintain the original behavior where the top-left corner of the diagram remains fixed. We have provided a code snippet to demonstrate how to achieve this.

this.diagram1.Controller = new CustomDiagramController();

public class CustomDiagramController : DiagramController
{
   public override System.Drawing.RectangleF GetBoundingRect(System.Collections.ICollection nodes, MeasureUnits units)
   {
       Model model = this.Model;

       // get model node collection
       NodeCollection modelNodes = Model.Nodes;

       // get content bounds
       RectangleF rcNodeBounds;

       SizeF m_originoffset = new SizeF(new PointF(0, 0));
       RectangleF returnBounds = new RectangleF(m_originoffset.ToPointF(), SizeF.Empty);
       foreach (Node node in modelNodes)
       {
           //Caluculates the total bounds of the model content
           rcNodeBounds = ((IUnitIndependent)node).GetBoundingRectangle(model.MeasurementUnits, false);
           returnBounds = RectangleF.Union(returnBounds, rcNodeBounds);
       }
       //Updates the position of the origin based on the model content.
       m_originoffset.Width -= returnBounds.X;
       m_originoffset.Height -= returnBounds.Y;

       //Updates the Model's size
       returnBounds.Width = Math.Max(model.MinimumSize.Width + m_originoffset.Width, returnBounds.Width);
       returnBounds.Height = Math.Max(model.MinimumSize.Height + m_originoffset.Height, returnBounds.Height);
       return returnBounds;
   }

}

Conclusion:

I hope you enjoyed learning about how to prevent the diagram area from scrolling down while adding a new element in WinForms Diagram

You can refer to our WinForms Diagram feature tour page to learn about its other groundbreaking feature representations and documentation. You can also explore our WinForms Diagram example to understand how to create and manipulate data.

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