Adding an Interactive Selection Routine using SelectObject(...) and SelectObjects(...)

Adding an interactive selection routine also allows you to generalize your journal and make it more useful. Limiting, or filtering the allowed selection types is vital to getting your journal to work correctly.  The selection object will give you the power and flexibility needed for selecting one or more objects of one or more different types.

Using the Basic SelectObject(...)

This method of the selection object allows the user to select only a single object of a given type. To use it, you’ll need a reference to the UserInterface (UI) object (Journals that reference the UI object will not be able to run in batch mode). As of this writing, there are at least 3 ways to call the SelectObject Method. Technically speaking, the method is overloaded. If you don’t know or don’t care what that means, don’t worry the code samples will still work for you.

Here’s the signature of the first version:

Public Function SelectObject( _
    message As String, _
    title As String, _
    scope As Selection.SelectionScope, _
    keepHighlighted As Boolean, _
    typeArray As Selection.SelectionType(), _
    <OutAttribute> ByRef object As NXObject, _
    <OutAttribute> ByRef cursor As Point3d _
) As Selection.Response

The first 5 parameters are input to the function, setting certain desired behavior for the selection routine. The last 2 parameters are variables that will be modified (returned) by the function (note the <OutAttribute> tags).

When the method is called, a small dialog box will be presented to the user. This dialog box looks similar to the Export Parasolid dialog box, but with even fewer options. You can specify the title and prompt of this dialog box with the message and title parameters. The title parameter you pass in will appear in the title bar of the dialog box and the message parameter will show up in the cue line (which may be above or below the graphics window depending on the user interface layout options).

Limiting the SelectObject(...)

Next up, you can limit where a valid selection can take place with the scope parameter. The available options here are:

• Selection.SelectionScope.UseDefaultSelection
• SelectionScope.WorkPart - limit selection to only entities within the work part
• Selection.SelectionScope.AnyInAssembly - select from pretty much anywhere
• Selection.SelectionScope.WorkPartAndOccurrence - limit selection to the work part and its components

A boolean parameter (True or False), keepHighlighted, will control the highlight behavior of the selected object. A False value should be passed in, unless you have a good reason to keep the object highlighted for longer than what is normal for NX. Should you decide that keepHighlighted is what you need, you will need to add additional code to un-highlight the objects where you see fit. If you are using the dialog styler, you may need the control that keepHighlighting = True will give you. Should your journal end before the objects have been unhighlighted, they will remain highlighted until the user selects/deselects the object, or runs a part cleanup with the ‘Remove Extraneous Highlighting’ option; an annoyance your users will likely complain about. You have been warned.

The typeArray parameter is an array of Selection.SelectionType objects. The values you choose to pass in to this parameter will limit the types of objects allowed for selection. The available values to use are:

• Selection.SelectionType.All
• Selection.SelectionType.Features
• Selection.SelectionType.Curves
• Selection.SelectionType.Faces
• Selection.SelectionType.Edges
• Selection.SelectionType.CurvesAndEdges

If you want to limit selection to faces and edges, your type array would look like this:

Dim typeArray() As Selection.SelectionType = _
   {Selection.SelectionType.Faces, _
   Selection.SelectionType.Edges}

(Note: the variable does not need to be named typeArray, any valid variable name will work)
SelectionType.All is a little misleading, in reality it seems to mean all except faces, edges, and features. If you want to give the user the ability to select from anything use:

Dim typeArray() As Selection.SelectionType = _
   {Selection.SelectionType.All, _
   Selection.SelectionType.Faces, _
   Selection.SelectionType.Edges, _
   Selection.SelectionType.Features}

By using the filters on the selection toolbar, the user will be able to further narrow the selection type. For instance, if the journal specifies SelectionType.CurvesAndEdges, the user can filter his selection to only curves; he cannot, however, broaden the filter to include objects other than curves or edges.

The object variable passed in will be set to a reference of the object the user picked and the cursor variable will return the cursor location when the object was picked; unless the user opted to select by name (the dialog box mentioned earlier allows for input of an object’s name) in which case cursor would be undefined.

An example program follows, I encourage you to change the members of typeArray to see what affect they have on the selection.

Option Strict Off
Imports System
Imports NXOpen
 
Module NXJournal
Sub Main
 
Dim theSession As Session = Session.GetSession()
Dim workPart As Part = theSession.Parts.Work
Dim displayPart As Part = theSession.Parts.Display
Dim lw As ListingWindow = theSession.ListingWindow
Dim mySelectedObject As NXObject
 
lw.Open
 
'Continue prompting for a selection until the user
'  presses Cancel or Back.
Do Until SelectAnObject("Hey, select something", _
                       mySelectedObject) = Selection.Response.Cancel
   lw.WriteLine("Object Tag: " & mySelectedObject.Tag)
   lw.WriteLine("Object Type: " & mySelectedObject.GetType.ToString)
   lw.WriteLine("")
Loop
 
' The close method closes the text stream to the window,
'   it does not close the window itself
'   (use the .CloseWindow() method for that).
' Also, if you are using the listing window to write
'   to a file, the close method will clean up and close the file.
lw.Close
 
End Sub
 
    Function SelectAnObject(prompt As String, _
               ByRef selObj As NXObject) As Selection.Response
 
       Dim theUI As UI = UI.GetUI
       Dim cursor As Point3d
       Dim typeArray() As Selection.SelectionType = _
           {Selection.SelectionType.All, _
               Selection.SelectionType.Faces, _
               Selection.SelectionType.Edges, _
               Selection.SelectionType.Features}
 
       Dim resp As Selection.Response = theUI.SelectionManager.SelectObject( _
               prompt, "Selection", _
               Selection.SelectionScope.AnyInAssembly, _
               False, typeArray, selobj, cursor)
 
       If resp = Selection.Response.ObjectSelected Or _
               resp = Selection.Response.ObjectSelectedByName Then
           Return Selection.Response.Ok
       Else
           Return Selection.Response.Cancel
       End If
 
    End Function
 
End Module

Using SelectObjects(...)

If you need to allow selection of multiple objects, try out the SelectObjects(...) method. The parameter signature of this method is very similar to the single select version; two notable exceptions are you must create and pass in an array variable to hold the selected object(s) and there is no cursor parameter (Point3d) passed to or returned from the function.

Option Strict Off
Imports System
Imports NXOpen
 
Module NXJournal
Sub Main
 
Dim theSession As Session = Session.GetSession()
Dim workPart As Part = theSession.Parts.Work
Dim displayPart As Part = theSession.Parts.Display
Dim lw As ListingWindow = theSession.ListingWindow
Dim mySelectedObjects as NXObject()
 
lw.Open
 
If SelectObjects("Hey, select multiple somethings", _
               mySelectedObjects) = Selection.Response.Ok Then
       lw.WriteLine("You selected " & mySelectedObjects.Length & " object(s)")
       lw.WriteLine("")
   For Each mySelObj As NXObject in mySelectedObjects
       lw.WriteLine("Object Tag: " & mySelObj.Tag)
       lw.WriteLine("Object Type: " & mySelObj.GetType.ToString)
       lw.WriteLine("")
   Next
 
End if
 
' The close method closes the text stream to the window,
'   it does not close the window itself
'   (use the .CloseWindow() method for that).
' Also, if you are using the listing window to write
'   to a file, the close method will clean up and close the file.
lw.Close
 
End Sub
 
    Function SelectObjects(prompt As String, _
               ByRef selObj as NXObject()) As Selection.Response
 
       Dim theUI As UI = UI.GetUI
       Dim typeArray() As Selection.SelectionType = _
           {Selection.SelectionType.All, _
               Selection.SelectionType.Faces, _
               Selection.SelectionType.Edges, _
               Selection.SelectionType.Features}
 
       Dim resp As Selection.Response = theUI.SelectionManager.SelectObjects( _
               prompt, "Selection", _
               Selection.SelectionScope.AnyInAssembly, _
               False, typeArray, selobj)
 
       If resp = Selection.Response.ObjectSelected Or _
               resp = Selection.Response.ObjectSelectedByName Or _
               resp = Selection.Response.OK Then
           Return Selection.Response.Ok
       Else
           return Selection.Response.Cancel
       End If
 
    End Function
 
End Module

Recap:

By using the SelectObject()or SelectObjects() methods, we can easily prompt the user, limit the selected object types, and even limit the user to the selection of a single object. These methods also provide for an easy way to allow the user to select anything in the file.

The drawback to the typeArray method of selection is it may not give enough control. What if you needed to limit selection to circular edges, for example? The bad news is this version of SelectObjects won’t get you there; the good news is there is a version that will. This level of granularity comes at a price - it is more difficult to set up, but that’s a story for another article on selection SelectObjectMaskTriple().

Objectives:

In this tutorial we have identified the four options of the selection routine, discussed their purposes, and looked at the code behind each option.