我的 SQL 数据库中有 40 行。我想每页显示 15 行。但是当我运行以下代码时，它只是一次又一次地打印前 15 行

Question

while (rdr.Read())
{
    if (itemCounter < itemPerPage)
    {
        e.Graphics.DrawString(rdr["cCode"].ToString(), new Font("Arial", 11, FontStyle.Regular), Brushes.Black, new Point(60, Ypos));
        e.Graphics.DrawString(rdr["cName"].ToString(), new Font("Arial", 11, FontStyle.Regular), Brushes.Black, new Point(120, Ypos));
        e.Graphics.DrawString(rdr["cShortAddress"].ToString(), new Font("Arial", 11, FontStyle.Regular), Brushes.Black, new Point(310, Ypos));
        e.Graphics.DrawString(rdr["cPhone"].ToString(), new Font("Arial", 11, FontStyle.Regular), Brushes.Black, new Point(580, Ypos));

        Ypos = Ypos + 22;
        itemCounter++;
    }
    else
    {
        Ypos = 182;
        e.HasMorePages = true;
    }
}
rdr.Close();

请帮助我，以便我可以控制循环。

我尝试了另一个循环。在for循环中也会出现类似的问题。我想在一页上打印0到14个索引数据，在另一页上打印15到29个索引数据，依此类推。

请了解我是否有任何方法可以通过for循环打印发票。谢谢。

for (i = itenCounter; i < totalItem; i++)
{
    rdr.Read();

    if (itemCounter < itemPerPage)
    {
        e.Graphics.DrawString(rdr["cCode"].ToString(), new Font("Arial", 11, FontStyle.Regular), Brushes.Black, new Point(60, Ypos));
        e.Graphics.DrawString(rdr["cName"].ToString(), new Font("Arial", 11, FontStyle.Regular), Brushes.Black, new Point(120, Ypos));
        e.Graphics.DrawString(rdr["cShortAddress"].ToString(), new Font("Arial", 11, FontStyle.Regular), Brushes.Black, new Point(310, Ypos));
        e.Graphics.DrawString(rdr["cPhone"].ToString(), new Font("Arial", 11, FontStyle.Regular), Brushes.Black, new Point(580, Ypos));

        Ypos = Ypos + 22;
        itemCounter++;
    }
    else
    {
        Ypos = 182;
        e.HasMorePages= true;
    }
}

itenCounter = itenCounter + itemPerPage;

Answer 1

以下是使用 Windows 窗体应用程序中的 PrintDocument 从 SQL 数据库打印每页 15 行的完整 C# 代码。

   public partial class Form1 : Form
   {
       public Form1()
       {
           InitializeComponent();
           printDocument.PrintPage += new PrintPageEventHandler(PrintPage);
           Button printButton = new Button
           {
               Text = "Print",
               Location = new Point(120, 10)
           };
           printButton.Click += PrintButton_Click;
           Controls.Add(printButton);
       }
       private PrintDocument printDocument = new PrintDocument();
      
       private SqlDataReader rdr;
       private int itemCounter = 0;
       private int itemsPerPage = 15;
       private int totalItemCount = 40; 
       private int currentPageIndex = 0;
       private void PrintButton_Click(object sender, EventArgs e)
       {
          
           StartPrint();
       }
       private void PrintPage(object sender, PrintPageEventArgs e)
       {
           if (rdr == null)
           {
               e.HasMorePages = false;
               return;
           }

           int startIndex = currentPageIndex * itemsPerPage;
           int Ypos = 182; 

           while (itemCounter < startIndex + itemsPerPage && itemCounter < totalItemCount)
           {
               if (rdr.Read())
               {
                  
                   e.Graphics.DrawString(rdr["cCode"].ToString(), new Font("Arial", 11, FontStyle.Regular), Brushes.Black, new Point(60, Ypos));
                   e.Graphics.DrawString(rdr["cName"].ToString(), new Font("Arial", 11, FontStyle.Regular), Brushes.Black, new Point(120, Ypos));
                   e.Graphics.DrawString(rdr["cShortAddress"].ToString(), new Font("Arial", 11, FontStyle.Regular), Brushes.Black, new Point(310, Ypos));
                   e.Graphics.DrawString(rdr["cPhone"].ToString(), new Font("Arial", 11, FontStyle.Regular), Brushes.Black, new Point(580, Ypos));

                   Ypos += 22; 
                   itemCounter++;
               }
           }
          
           if (itemCounter < totalItemCount)
           {
               e.HasMorePages = true; 
               currentPageIndex++; 
           }
           else
           {
               e.HasMorePages = false; 
               ResetCounters(); 
           }
       }

       private void ResetCounters()
       {
           itemCounter = 0;
           currentPageIndex = 0;
       }

       private void StartPrint()
       {
          
           using (SqlConnection conn = new SqlConnection("Data Source=(localdb)\\ProjectModels;Initial Catalog=MyData;Integrated Security=True;Connect Timeout=30;Encrypt=False;TrustServerCertificate=False;ApplicationIntent=ReadWrite;MultiSubnetFailover=False"))
           {
               conn.Open();
               using (SqlCommand cmd = new SqlCommand("SELECT cCode, cName, cShortAddress, cPhone FROM [dbo].[TestTable]", conn))
               {
                   rdr = cmd.ExecuteReader();
                   printDocument.Print();
               }
           }
       }
     

   }