Open CASCADE Technology  7.0.0
OCCT CSharp sample

This sample demonstrates how to use OCCT libraries in .Net application written using CSharp and Windows Forms or Windows Presentation Foundation (WPF).

The connection between .Net and OCCT (C++) level is provided by proxy library OCCProxy, written in C++/CLI. The proxy library contains a single ref class encapsulating OCCT viewer and providing the functionality to manipulate this viewer and to import / export OCCT shapes from / to several supported CAD file formats (IGES, STEP, BREP).

The sample implements two approaches to the development of a user interface with C#. Both applications provide the same functionality as the standard OCCT Import/Export sample. The first project is called IE_WinForms and uses Windows Forms for GUI. The second application is called IE_WPF_WinForms and uses Windows Presentation Foundation.

Note a few important details:

  • OCCT template class NCollection_Haft is used to encapsulate C++ class into a field of ref class;
  • It is necessary to explicitly set the target platform for C# assemblies to x86 in project Properties - Build to work consistently on 64-bit systems with OCCT libraries built in 32-bit mode;
  • this sample demonstrates indirect method of wrapping C++ to C# using a manually created proxy library. There is an alternative method of wrapping individual OCCT classes to C# equivalents to make their full API available to a C# user and to let the code be programmed on C# level similarly to C++ one. See the description of OCCT C# Wrapper in Advanced Samples and Tools at
  • in WPF sample, WinForms control is used to encapsulate OCC viewer since WPF does not provide the necessary interface to embed OpenGl view. Other possible solution could be to render OpenGl scene in an off-screen buffer and to map it to WPF control as an image. That approach would allow using all WPF features to control the OCCT viewer.

Run msvc.bat to start MS Visual Studio for building the sample. Note that project files are provided only for VS 2010, you can open them in newer versions of Visual Studio the using automatic converter.

After conversion check option Target framework in the properties of C# projects (tab Application) to make sure that it corresponds to the version set in the properties of C++ projects (e.g. .Net Framework 4.0 for VS 2010).

Run run_winforms.bat or run_wpf.bat to launch the corresponding sample.

Note that all batch scripts use the configuration defined in OCCT custom.bat file as default; you can provide arguments specifying VS version, bitness, and mode to override these settings, e.g.:

> msvc.bat vc10 win64 Debug