Nevron Forum

Cycling through shapes on a diagram editor

https://www.nevron.com/Forum/Topic4709.aspx

By Ron Sawyer - Wednesday, January 5, 2011

I have tried to implement this but am just not quite getting it...

In the editor, I want an easy way to select a shape that is underneath the current shape - but I don't want to send the current shape behind.

Let me give an example to try to better explain.

I have a circle on a diagram. Above it is a triangle, and above that is a rectangle.

The first click would select the rectangle so I could edit its properties.
I could then click in the same location to select the next shape below it - in this case the triangle.
I could then click again in the same location to select the next shape below that - the circle.

I want to preserve their Z-Order in the end diagram, I just want to edit the circle's properties without moving the shapes above it (or changing their Z-orders.)

Is this easily done?
By Nevron Support - Wednesday, January 5, 2011

Hi,

You can get all 2D shapes under the mouse cursor using the following piece of code:

 

NPointF location = view.GetMousePositionInDevice();

NHitTestContext hitTestContext = view.ProvideDocumentHitTestContext();

NNodeList nodes = document.HitTest(location, -1, NFilters.Shape2D, hitTestContext);

                                                           

To select one of the shapes use:

 

view.Selection.SingleSelect(nodes[index]);
By Ron Sawyer - Wednesday, January 26, 2011

Thank you for the very quick reply - and my apologies for not responding sooner.

The code you provided allowed me to add a solution that the product manager is happy with - and so things are mostly good. It isn't exactly as I described, but he is content.

I tried a different solution, which kind of works, but sometimes causes an exception. Since the other solution works, we aren't too worried, but I am kind of interested in what I'm missing/doing wrong.

In the nDrawingView1_Click event I check to see if the control key and the alt key is down. If so, I try to cycle through the shapes under the mouse (in our case, we have a class attached to the tag to store some custom properties) and then try to do a single select on the next shape under the mouse. Most of the time this works. Sometimes I get an exception. I am thinking that maybe the _click event is the wrong event? Is there a better one? here is the code:

if ((Control.ModifierKeys & Keys.Control) == Keys.Control)
{



if ((Control.ModifierKeys & Keys.Alt) == Keys.Alt)
{
try
{
//////////////////////////////////////
// Get a list of nodes under the
// mouse ointer
NPointF location = nDrawingView1.GetMousePositionInDevice();
NHitTestContext hitTestContext = nDrawingView1.ProvideDocumentHitTestContext();
NNodeList nodes = nDrawingDocumentEditors.HitTest(location, -1, NFilters.Shape2D, hitTestContext);
if (nodes != null)
{
if (nodes.Count > 1)
{
/////////////////////////////////////
// Go through each node and grab
// its tag.
int MyNodesSelectedIndex = 0;
for (int ii = 0; ii < nodes.Count; ii++)
{
NShape LclShape;
LclShape = nodes[ii] as NShape;
if (LclShape != null)
{
MentorCustomShapeTagBase LclTag;
LclTag = LclShape.Tag as MentorCustomShapeTagBase;
if (LclTag != null)
{
/////////////////////////////////////
// Compare the current tag with the
// tag on the property grid. If it
// is the right one, select the next
// one or wrap to the beginning of the
// list
if (propertyGrid1.SelectedObject != null)
{
if (LclTag == propertyGrid1.SelectedObject)
{
MyNodesSelectedIndex = ii + 1;
if (MyNodesSelectedIndex >= nodes.Count)
{
MyNodesSelectedIndex = 0;
}
break;
}
}
}
} // end if
}
try
{
nDrawingView1.Selection.SingleSelect(nodes[MyNodesSelectedIndex]);
}
catch (Exception ex)
{
string LclString = ex.Message;

}

}
}
}
catch (Exception ex)
{
string LclString = ex.Message; // for debug purposes
}
}
}
By Nevron Support - Friday, January 28, 2011

Hi Ron,

What's the exception you get? May be it is best to send your sample project to support@nevron.com. We'll check on it and tell you what's wrong.
By Ron Sawyer - Friday, January 28, 2011

I was *afraid* you'd ask for that...

The project is too large to send at this time - but it is fair enough that you want a sample. I think for now we'll stick with the solution we have and try to create a sample sometime in the future.

As always, thanks for the quick reply.