As title, in the use of QWT graph, need to read the file, every time read a new file, need to delete the last curve drawing, the new data mapped, now in this case, the method of using the BBS
Qwtplot - & gt; DetachItems ();
Qwtplot - & gt; Replot;
Find old curve has not been cleared, a new curve is added directly, to solve how to solve this problem