C＃中的打印预览制作问题

如何解决C＃中的打印预览制作问题

当我单击打印预览按钮时。它显示了我列出的项目。但是当我关闭打印预览屏幕并添加更多项目并单击打印预览时。它仅显示我稍后输入的项目。我清除了旧添加的项。

这是我正在尝试的代码

private void printDocument1_PrintPage(object sender,System.Drawing.Printing.PrintPageEventArgs e)
{
    e.Graphics.DrawString("Date: " + DateTime.Now.ToShortDateString(),new Font("Calibri",11,FontStyle.Regular),Brushes.Black,new Point(300,150));
    e.Graphics.DrawString("Customer Name: " + customername.Text.Trim(),new Point(20,150));

    int yPos = 200;
    int xPos = 20;
    int brandyPos = 180;

    for (int i = numberOfItemsPrintedSoFar; i < beltlist.Count; i++)
    {
        numberOfItemsPerPage++;

        if (numberOfItemsPerPage <= 15 && count <= 3)
        {
            numberOfItemsPrintedSoFar++;

            if (numberOfItemsPrintedSoFar <= beltlist.Count)
            {

                e.Graphics.DrawString(beltlist[i].BrandName,new Point(xPos,brandyPos));
                brandyPos = yPos + 20;
                e.Graphics.DrawString(beltlist[i].BeltSize.ToString() + "--" + beltlist[i].QTY.ToString(),yPos));
                yPos += 20;

            }
            else
            {
                e.HasMorePages = false;
            }
        }
        else
        {
            count++;
            yPos = 180;
            xPos += 150;
            numberOfItemsPerPage = 0;
            if (count > 3)
            {
                e.HasMorePages = true;
                xPos = 20;
                count = 1;
                return;
            }
        }
    }
}