Hi, Stoyo

First of all thanks for your help.

I working with diagram, as code here

dim BGBounds as rect = New Rect(0, 0, TemplateWidth, TemplateHeight)
BGNode = diagram.Factory.CreateContainerNode(BGBounds)
With BGNode
.Id = BackgroundID
.Constraints.KeepInsideParent = True
.AllowRemoveChildren = False
.Locked = True
.ImageAlign = ImageAlign.Center
.Transparent = True
.Name = BackgroundName
End With
With diagram
.AutoResize = AutoResize.None
.Behavior = Behavior.Modify
.AlignToGrid = True
.AutoScroll = True
.MeasureUnit = MindFusion.Diagramming.Silverlight.GraphicsUnit.Pixel
.AdjustmentHandlesSize = 10
.ShapeBrush = NodeBrush
.Bounds = BGBounds
.ShowGrid = True
End With


This code show canvas area in my screen. I can draw any shape node and also increase border size from numeric up down button. Code is here:-

For Lop = 0 To diagram.Nodes.Count - 1
If diagram.Nodes(Lop).Selected = True Then
Dim node As ShapeNode = diagram.Nodes(Lop)
Dim Pen As Pen = node.Pen
node.Pen = Nothing
node.Pen = Pen
node.StrokeThickness = spnBorderSize.Value
End If
Next Lop

spnBorderSize is name of numeric up down button. The problem is, If the control is placed very near the the canvas area, on increasing border thickness the increased thickness gets out of the canvas area. I want to restrict this within the canvas area. also when I move the control somewhere in the middle of the canvas, I should see the whole border with the specified thickness.

As you can see in snap shot. Blue line show canvas area boundary.

Thanks in advance.