趋势图片保存

    private void btn_Save_Click(object sender, EventArgs e)
    {
        SaveFileDialog saveFileDialog = new SaveFileDialog();
        saveFileDialog.Filter = "图片文件(*.jpg)|*.jpg|所有文件|*.*";
        saveFileDialog.Title = "历史趋势图片";
        saveFileDialog.FileName = "历史趋势图片" + DateTime.Now.ToString("yyyyMMddHHmmss");
        saveFileDialog.DefaultExt = "jpg";
        saveFileDialog.AddExtension = true;

        if (saveFileDialog.ShowDialog() == DialogResult.OK)
        {
            this.chart_ActualTrend.SaveAsImage(saveFileDialog.FileName);

            if (new frmWithAck("打开趋势图片", "图片保存成功，是否立即打开？").ShowDialog() == DialogResult.OK)
            {
                Process.Start(saveFileDialog.FileName);
            }
        }
    }