SampleCsModelessForm.SampleCsForm.button1_Click C# (CSharp) Method

        private void button1_Click(object sender, EventArgs e)
        {
            // Since our form is modeless, the user can run commands
              // while our form is visible, including the Open command,
              // which closes the current document and opens a new one.
              // Thus, it's best to always ask for the active document
              // instead of maintaining a reference to the document passed
              // to the command that created this form.
              MRhinoDoc doc = RhUtil.RhinoApp().ActiveDoc();
              if (null != doc)
              {
            On3dPoint a = new On3dPoint(0.0, 0.0, 0.0);
            On3dPoint b = new On3dPoint(5.0, 5.0, 5.0);
            OnLine line = new OnLine(a, b);
            doc.AddCurveObject(line);
            doc.Redraw();
              }
        }