Code

class SwimlaneGrid : ISwimlaneGrid
{
	public SwimlaneGrid(MindFusion.Diagramming.Silverlight.Lanes.Grid laneGrid)
	{
		this.laneGrid = laneGrid;
	}

	public int GetColumnCount()
	{
		return laneGrid.ColumnCount;
	}

	public double GetColumnWidth(int index)
	{
		return laneGrid.ColumnHeaders[index].Width;
	}

	public int GetRowCount()
	{
		return laneGrid.RowCount;
	}

	public double GetRowHeight(int index)
	{
		return laneGrid.RowHeaders[index].Height;
	}

	public void SetColumnCount(int value)
	{
		// Do nothing to prevent columns from being dropped
	}

	public void SetColumnWidth(int index, double value)
	{
		laneGrid.ColumnHeaders[index].Width = value;
	}

	public void SetLeftMargin(double value)
	{
		laneGrid.LeftMargin = value - laneGrid.GetRowHeaderBounds().Width;
	}

	public void SetRowCount(int value)
	{
		// Do nothing to prevent rows from being dropped
	}

	public void SetRowHeight(int index, double value)
	{
		laneGrid.RowHeaders[index].Height = value;
	}

	public void SetTopMargin(double value)
	{
		laneGrid.TopMargin = value - laneGrid.GetColumnHeaderBounds().Height;
	}

	private MindFusion.Diagramming.Silverlight.Lanes.Grid laneGrid;
} 

Code

layout.SwimlaneGrid = new SwimlaneGrid(diagram.LaneGrid);