Use custom hidden ObjectManipulator to move entities

This sample uses a hidden custom ObjectManipulator to move the entities.
After the entity is selected with a mouse click, you can start the dragging of the selected entity on view.
When the viewport is clicked again the translation is applied to the entities.

using devDept.Eyeshot;
using devDept.Eyeshot.Entities;
using devDept.Geometry;

class MyOM : ObjectManipulator
{
    public MyOM(ObjectManipulator another) : base(another.Size, another.Visible, another.ShowOriginalWhileEditing, another.Translate, another.TranslateX,
    another.TranslateY, another.TranslateZ, another.RotateX, another.RotateY, another.RotateZ, another.RotationStep, another.TranslationStep)
    {

    }

    private bool first = true;

    public void EnableDragging(bool enable, Viewport viewport, MouseEventArgs e)
    {
        if (enable)
        {                
            Enable(new Identity(), true);
            PickedEntity = Entities[0];
        }
        else
        {
            PickedEntity = null;
        }

        OnMouseDown(e, viewport);

        first = true;
    }

    protected override bool OnMouseUp(System.Windows.Forms.MouseEventArgs e, Viewport viewport)
    {
        var res = base.OnMouseUp(e, viewport);

        Dragging = true;

        return res;
    }

    protected override bool OnDrag(ref System.Drawing.Point lastPoint, System.Drawing.Point curPoint, Viewport viewport)
    {
        if (first)
            lastPoint = curPoint;

        first = false;
        return base.OnDrag(ref lastPoint, curPoint, viewport);

    }

    public override void Draw(RenderParams data)
    {
        //base.Draw(data);
    }
}

public Form1()
{

    InitializeComponent();
    ...        
    viewportLayout1.Click += VpOnClick;
}

private bool dragging = false;
private int entityIndex = -1;

private void VpOnClick(object sender, EventArgs eventArgs)
{
    if (viewportLayout1.ActionMode != actionType.None)
        return;

    if (dragging)
    {
        viewportLayout1.ObjectManipulator.Apply();
        viewportLayout1.Entities.Regen();
        viewportLayout1.Entities[entityIndex].Selected = false;
    }
    else
    {
        MouseEventArgs me = (MouseEventArgs) eventArgs;            
        entityIndex = viewportLayout1.GetEntityUnderMouseCursor(me.Location);
        if (entityIndex < 0)
            return;
        viewportLayout1.Entities[entityIndex].Selected = true;
        ((MyOM)viewportLayout1.ObjectManipulator).EnableDragging(true, viewportLayout1.Viewports[0], me); 
    }
    
    viewportLayout1.Invalidate();
    dragging = !dragging;
}

protected override void OnLoad(EventArgs e)
{
    viewportLayout1.Entities.Add(Mesh.CreateSphere(10, 10, 10));

    viewportLayout1.ObjectManipulator = new MyOM(viewportLayout1.ObjectManipulator);
    viewportLayout1.ObjectManipulator.ShowOriginalWhileEditing = false;
    viewportLayout1.CompileUserInterfaceElements();  

    viewportLayout1.ZoomIn(120);
    viewportLayout1.PanUp(200); 
}