saveFileDialog1.Title = "保存";
            saveFileDialog1.Filter = "*.png|*.png";
            saveFileDialog1.RestoreDirectory = true;
            if (saveFileDialog1.ShowDialog() == DialogResult.OK)
            {
                timer1.Enabled = true;
            }

timer1.Enabled = false;
            Bitmap bit = new Bitmap(this.Width, this.Height);//實例化一個和窗體一樣大的bitmap
            Graphics g = Graphics.FromImage(bit);
            g.CompositingQuality = CompositingQuality.HighQuality;//質量設為最高
            //g.CopyFromScreen(this.Left, this.Top, 0, 0, new Size(this.Width, this.Height));//保存整個窗體為圖片
            g.CopyFromScreen(chartType.PointToScreen(Point.Empty), Point.Empty, chartType.Size);//只保存某個控件
            bit.Save(saveFileDialog1.FileName);//默認保存格式為PNG，保存成jpg格式質量不是很好
            if (File.Exists(saveFileDialog1.FileName.ToString()))
            {
                MessageBox.Show("截圖成功！");
                return;
            }