How to add cursor in CW3DGraph?

[小榕]

My CVI version is 7.0, not Measurement Studio for Vx.

I cannot add a cursor on CW3DGraph.

Can someone fix it?

[小榕]

Who could give me a example about using Cursor3D with 3DGraph in cvi 7.0, not measurement studio for Vx. And I couldn't find a example about Cursor3D in "CVI70\samples" directory.
In my project, I cannot add a cursor in 3DGraph control. my code as following:
   
CW3DGraphLib__DCWGraph3DGetPlots(gGraph, NULL, &plots));

//here, the 'status' value is 0
 status = CW3DGraphLib_CWCursors3DAdd (plots, NULL, &val);

//here, the 'status' value is -2147467262.the succedent 'status' is also -2147467262
 status = CW3DGraphLib_CWCursors3DItem (val, NULL, CA_VariantInt(1), &cursor);
 status = CW3DGraphLib_CWCursor3DSetName (gGraph, NULL, "cursor");//the 'status'
 status = CW3DGraphLib_CWCursor3DSetEnabled (cursor, NULL, VTRUE);
 status = CW3DGraphLib_CWCursor3DSetVisible (cursor, NULL, VTRUE);
 status = CW3DGraphLib_CWCursor3DSetNameVisible (cursor, NULL, VTRUE);
 status = CW3DGraphLib_CWCursor3DSetColor (cursor, NULL, MakeColor (0, 0, 1));
 status = CW3DGraphLib_CWCursor3DSetXPosition (cursor, NULL, 2.0);
 status = CW3DGraphLib_CWCursor3DSetYPosition (cursor, NULL, 2.0);
 status = CW3DGraphLib_CWCursor3DSetZPosition (cursor, NULL, 2.0);
 status = CW3DGraphLib_CWCursor3DSetPositionVisible (cursor, NULL, VTRUE);
 status = CW3DGraphLib_CWCursor3DSetLineWidth (cursor, NULL, 5.0);