如何从.Net C#和SQL服务器windows应用导出PDF

Question

I want to export pdf file from my desktop application. I tried following code snap

        private void button1_Click(object sender, EventArgs e)
        {
            Document doc = new Document();
            PdfWriter.GetInstance(doc, new FileStream("myPdf.pdf",FileMode.Create));
            doc.Open();
            SqlConnection con = new SqlConnection(connectionString);
            if (con.State == ConnectionState.Closed)
            {
                con.Open();
            }

            SqlCommand cmd = new SqlCommand("SELECT b.date,a.TotalIncome,b.TotalExpense FROM (SELECT c.date, sum(c.amout) as TotalIncome FROM (SELECT name FROM category_tbl where type = 'Income') a, transactions c where c.type = a.name group by c.date) a, (SELECT c.date, sum(c.amout) as TotalExpense FROM (SELECT name FROM category_tbl where type = 'Expense') a, transactions c where c.type = a.name group by c.date) b", con);
            SqlDataReader dr = cmd.ExecuteReader();


            if (dr.Read())
            {
                Paragraph p1 = new Paragraph(dr.GetValue(0).ToString());
                Paragraph p2 = new Paragraph(dr.GetValue(1).ToString());
                Paragraph p3 = new Paragraph(dr.GetValue(2).ToString());
                doc.Add(p1);
                doc.Add(p2);
                doc.Add(p3);
                doc.Close();
                MessageBox.Show("PDF create");
            }



        }

Then I got the following output. Here I got only 1st row in SQL output.

5/16/2022 12:00:00 AM
12000
120

But I need to get all results in the table which are come from the SQL query, like this

date	Income	Expenses
5/16/2022 12:00:00 AM	12000	120
5/28/2022 12:00:00 AM	15000	145
6/02/2022 12:00:00 AM	3200	60
.	.	.
.	.	.

So, I want to know how to update the code for getting my achievement

Thank you!!!

Answer 1

Your code executes reader.read() only once which means you will process only first row. Try to use it this way

while(dr.Read())
{
   Paragraph p1 = new Paragraph(dr.GetValue(0).ToString());
   Paragraph p2 = new Paragraph(dr.GetValue(1).ToString());
   Paragraph p3 = new Paragraph(dr.GetValue(2).ToString());
   doc.Add(p1);
   doc.Add(p2);
   doc.Add(p3);
}
doc.Close();
MessageBox.Show("PDF create");

Also consider adding using statement for your sql connection, or add con.Close() at the end.