打印时放大或缩小

using System.Drawing.Printing;Double  myZoom = 1.0;

 private void toolStripButton5_Click(object sender, EventArgs e)//放大{    myZoom += 0.1;    printPreviewControl1.Zoom = myZoom;}

 private void toolStripButton6_Click(object sender, EventArgs e)//縮小{    myZoom -= 0.1;    printPreviewControl1.Zoom = myZoom;}