Object Array Sample
Source code for Object Array sample is available in Samples\NET\VB
folder of the installation directory. It is recommended to
copy the folder to location outside of the installation folder
before loading or compilation.
ObjArray is an .NET Windows Forms application, which demonstrates dynamic creation of objects.
See also C# Object Array sample
C++ Object Array sample
All VB .NET Samples, Visual Basic .NET Samples,
All samples
Running the application
Controls on the right allow navigation between objects in the currently
loaded model. (see Structure of DInsight models). They
represent a simplified version of Model Explorer of 3D Debugger.
Children group displays number of children in the current object and allows to
make current one of them. The current object is highlighted in 3D with blue
color and its name is displayed at the top of the dialogue. On load
"Children" group displays information about objects in the model,
meaning that the whole model is considered as the top object in the
hierarchy.
"Delete" button deletes the child selected in the "Child"
edit box.
"Switch to parent" button on the top of the dialogue makes parent the
current object.
"Position" edit boxes allow modification of location of the current
object.
"New Child" group allows adding new objects to the model or new
children to the current object.
File submenu allows saving and loading models.
"Current Object" submenu contains operations with the model
structure:
Operations
"Delete" command deletes the child selected in the "Child"
edit box.
"Detach" command makes the current object independent top level
object of the model. On this command nothing will change in the 3D view. To make
sure that the command was carried out try to modify position of the current
object using "Position" edit boxes. The object should move
independently of its previous parent.
"Join" command makes the first top level object (different from the
current) child
of the current object. This command is invalid when a top object is being attached to
its child. As the result the object will move together with its parent.
Implementation
The most important work specific to this sample is done
using IArray interface. IArray is a topological interface, which means it
changes structure of the model rather than changing its parameters. Actions
performed by IArray depend on context. In this sample IArray adds or deletes
child objects from/to the entity or model it was queried from. It is done in
ButtonAdd_Click() and ButtonDelete_Click() methods of
ObjArrayForm class.
New objects are added in ButtonAdd_Click() handler. Depending on
selection in Type radio button group either NewStandardObjectForm or
NewGenericObjectForm is displayed. NewStandardObjectForm uses
IStdShape interface to create
new objects. NewGenericObjectForm uses Object
Generators to demonstrate more flexible but more complex object creation.
NewGenericObjectForm.Create3DS()
method
creates new Sect3DGeneratorClass object, which is a generic constructor of 3D entity objects.
Sect3DGeneratorClass has a single interface I3DSectionGenerator, which is queried
immediately from the object. Creation of the actual 3D Entity is done by using Create() method of
I3DSectionGenerator. Create() returns an
ISection interface, implemented by the
new entity, which is used later to add to the array of objects of the model or
parent entity. Prior to that, default parameters for the required entity are
collected into a DI3DSectInfo structure by Set3DSDefaults() function.
Method NewGenericObjectForm.CreateSOR() of the form does the same job for Surface Of
Revolution type of objects. All other generic objects are constructed with the
help of DIObjGenerator.
Suggested exercise
Add operation to change order of top level object in the model.
|