void GLCanvas2D::OnPaint(System::Windows::Forms::PaintEventArgs^ e)
{
    // Save previous context and make our context current

    HDC mhOldDC = wglGetCurrentDC();
    HGLRC mhOldGLRC = wglGetCurrentContext();
    wglMakeCurrent(mhDC, mhGLRC);

    /* Drawing code goes here
    ....
    .... */

    // Restore previous context

    wglMakeCurrent(mhOldDC, mhOldGLRC);
}