My code block works very slowly

Question

1.00/5 (1 vote)

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I'm trying to batch record using windows form. But When I click button to save, it works very slowly especially in this code block. Do you have a solution?

C#

int i = 0;
    List<int> ChkedRow = new List<int>();

    if (dataGridView1.Rows.Count > 0)

        for (i = 0; i <= dataGridView1.RowCount - 1; i++)
        {
            if (Convert.ToBoolean(dataGridView1.Rows[i].Cells["oid"].Value) == true)
            {
                ChkedRow.Add(i);
            }
        }
    if (ChkedRow.Count == 0)
    {
        MessageBox.Show("Geziye katılacak öğrenci seçiminde bulunmadınız!");
        return;
    }

What I have tried:

C#

private void button1_Click(object sender, EventArgs e)
{
    int i = 0;
    List<int> ChkedRow = new List<int>();

    if (dataGridView1.Rows.Count > 0)

        for (i = 0; i <= dataGridView1.RowCount - 1; i++)
        {
            if (Convert.ToBoolean(dataGridView1.Rows[i].Cells["oid"].Value) == true)
            {
                ChkedRow.Add(i);
            }
        }
    if (ChkedRow.Count == 0)
    {
        MessageBox.Show("Geziye katılacak öğrenci seçiminde bulunmadınız!");
        return;
    }
    progressBar1.Visible = true;
    label5.Visible = true;
    backgroundWorker1.WorkerReportsProgress = true;
    backgroundWorker1.RunWorkerAsync();

    foreach (int j in ChkedRow)
    {
        try
        {
            var val1 = dataGridView1.Rows[j].Cells["tcno"].Value;
            var val2 = dataGridView1.Rows[j].Cells["ono"].Value;
            var val3 = dataGridView1.Rows[j].Cells["isim"].Value;
            var val4 = dataGridView1.Rows[j].Cells["soyisim"].Value;
            var val5 = dataGridView1.Rows[j].Cells["cinsiyet"].Value;
            var val6 = dataGridView1.Rows[j].Cells["dtarihi"].Value;
            var val7 = dataGridView1.Rows[j].Cells["sinifi"].Value;
            var val8 = dataGridView1.Rows[j].Cells["unvan"].Value;
            var val9 = dataGridView1.Rows[j].Cells["tel"].Value;
            var val10 = dataGridView1.Rows[j].Cells["vtel"].Value;
            var val11 = dataGridView1.Rows[j].Cells["kbaskani"].Value;

            using (var conn = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source = gezievrak2541.accdb; Jet OLEDB:Database Password = Fatih2541; Mode = ReadWrite"))
            {
                conn.Open();
                using (var cmd = new OleDbCommand("select * from gezilistemiz25 where adi = '" + val3 + "' and soyadi=  '" + val4 + "' ", conn))
                {
                    using (OleDbDataReader dr = cmd.ExecuteReader())
                    {
                        if (dr.Read())
                        {
                            while (dr.Read())
                            {
                                MessageBox.Show(" '" + val3 + " " + val4 + "' isimli öğrenciler veritabanında kayıtlıdır. Mükerrer kayıt yapılamaz. Lütfen kontrol ediniz.");
                            }
                        }
                        else
                        {
                            if (conn.State == ConnectionState.Closed)
                            {
                                conn.Open();
                            }

                            var cmdText = @"INSERT INTO  gezilistemiz25 (tcno,ono,adi,soyadi,cinsiyet,dtarihi,sinifi,unvani,tel,vtel,kbaskani) VALUES(@tcno,@ono,@adi,@soyadi,@cinsiyet,@dtarihi,@sinifi,@unvani,@tel,@vtel,@kbaskani)";
                            var komut = new OleDbCommand(cmdText, conn);

                            komut.Parameters.AddWithValue("@tcno", val1);
                            komut.Parameters.AddWithValue("@ono", val2);
                            komut.Parameters.AddWithValue("@isim", val3);
                            komut.Parameters.AddWithValue("@soyisim", val4);
                            komut.Parameters.AddWithValue("@sinifi", val5);
                            komut.Parameters.AddWithValue("@cinsiyet", val6);
                            komut.Parameters.AddWithValue("@unvan", val7);
                            komut.Parameters.AddWithValue("@dtarihi", val8);
                            komut.Parameters.AddWithValue("@tel", val9);
                            komut.Parameters.AddWithValue("@vtel", val10);
                            komut.Parameters.AddWithValue("@kbaskani", val11);
                            komut.ExecuteNonQuery();
                            komut.Dispose();
                            komut.Parameters.Clear();
                            conn.Close();
                            conn.Dispose();
                        }
                    }
                }
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }
    }
   MessageBox.Show("Seçtiğiniz öğrenciler gezi listesine eklendi.");
}

Posted 3-Aug-23 11:21am

Member 12505620

Updated 3-Aug-23 19:14pm

PIEBALDconsult

v2

Add a Solution

Comments

PIEBALDconsult 3-Aug-23 21:14pm

Well, for one thing, don't keep instantiating and throwing away the connection and command.
Create each once, use them many times, then let them Dispose (use using statements) for them.
Also, don't use the Convert class when a cast will do.

Richard Deeming 4-Aug-23 4:04am

"Slow" is the least of your problems!

Your code is vulnerable to SQL Injection[^]. NEVER use string concatenation/interpolation to build a SQL query. ALWAYS use a parameterized query.

Everything you wanted to know about SQL injection (but were afraid to ask) | Troy Hunt[^]
How can I explain SQL injection without technical jargon? | Information Security Stack Exchange[^]
Query Parameterization Cheat Sheet | OWASP[^]

2 solutions

Solution 2

Quote:
My code block works very slowly

Since 'slowly' is probably not the correct word, you need to define 'slowly'.
I guess that your code take a long time to complete.
since the offending part is rather short piece of code, one can suspect a huge amount of row to process. Because a fast piece of code processing millions of rows will take some time to complete, but this, we can't guess.
So how many records ?

Depending on how it is done, dynamic list resizing can turn ugly slow on huge lists.

In order to understand how your code spend time, it may be interesting to look at profiling.
Profiling (computer programming) - Wikipedia[^]

Posted 3-Aug-23 19:14pm

Patrice T

Comments

Member 12505620 4-Aug-23 1:39am

I mean it takes a long time to save. It saves multiple lines each time. I know this will take a long time. However, that is a very long time. My progress bar is also not displayed when I click the button.

CPallini 4-Aug-23 2:37am

5.

Patrice T 4-Aug-23 5:00am

Thank you.

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Eldon E Elledge · Accepted Answer · 2023-08-03T16:41:00

Solution 1

Try this and check the performance. There a few things hee that should help.

List<int> checkedRows = new List<int>();

foreach (DataGridViewRow row in dataGridView1.Rows)
{
    if (Convert.ToBoolean(row.Cells["oid"].Value))
    {
        checkedRows.Add(row.Index);
    }
}

if (checkedRows.Count == 0)
{
    MessageBox.Show("Geziye katılacak öğrenci seçiminde bulunmadınız!");
    return;
}

Posted 3-Aug-23 16:41pm

Eldon E Elledge

Comments

Member 12505620 3-Aug-23 23:49pm

Thnaks for your intrest Eldon.

Member 12505620 4-Aug-23 4:10am

Thanks for your intrest Eldon.

PIEBALDconsult 5-Aug-23 11:04am

Don't use the Convert class when a cast will suffice.