My code working fine but (logical error) help me

Question

4.00/5 (1 vote)

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C#

private void toolStripButton3_Click_1(object sender, EventArgs e)
        {

            int damage = Convert.ToInt16(numericUpDown1.Value);
            if (textBox2.Text == "")
            {
                errorProvider1.SetError(textBox2, "Provide Owner name");
            }
            else if (textBox3.Text == "")
            {
                errorProvider1.SetError(textBox3, "Provide Address");
            }
            else if ((maskedTextBox1.Text.Trim().Length <= 10))
            {
                MessageBox.Show("Provide full phone number");
            }
            else if (numericUpDown2.Value >= damage)
            {
                MessageBox.Show("check Damage quantity");
            }
            else
            {
                int a = 0, b = 0, c = 0;

                if (!int.TryParse(textBox5.Text,
                                    System.Globalization.NumberStyles.Integer,
                                    System.Globalization.CultureInfo.CurrentUICulture,
                                    out a))
                {
                    MessageBox.Show("u need to enter value");
                }

                else if (!int.TryParse(textBox9.Text,
                                    System.Globalization.NumberStyles.Integer,
                                    System.Globalization.CultureInfo.CurrentUICulture,
                                    out b))
                {
                    MessageBox.Show("u entered greater value");
                }
                else if (b > a)
                {
                    MessageBox.Show("ur amount greater then total");

                }
                else
                {
                    c = a - b;
                    textBox10.Text = c.ToString(System.Globalization.CultureInfo.CurrentUICulture);
                    
                    UGIcon.Open();
                    cmd = new SqlCommand ("update purchase set om='" + textBox2.Text + "', address='" + textBox3.Text + "', phone='" + maskedTextBox1.Text.ToString() + "',baled='" + numericUpDown2.Value + "',paid='" + textBox9.Text + "',status='" + textBox4.Text + "',balance='" + textBox10.Text + "' where cm='"+toolStripTextBox1.Text+"'", UGIcon);
                    SqlDataReader da;
                    da = cmd.ExecuteReader();
                    da.Close();
                    MessageBox.Show("Details has been updated sucessfully", "Update Window", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    UGIcon.Close();

                }
            }
        }

if i update data using WHERE clause "toolstriptextbox" (if match found in toolstriptextbox its updating and displaying messagebox as Update successfully and if not match found its not updating BUT STILL its displaying same messagebox as Update successfully)

Posted 25-Jan-13 21:11pm

selva_1990

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OriginalGriff · Accepted Answer · 2013-01-25T21:55:00

Don't use ExecuteReader with a UPDATE Query - use ExecuteNonQuery instead. It will return an integer value, which is the number of records affected. You can check this, and decide if there were any changes.

And do not concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Use Parametrized queries instead.

"i preferred this queries because in my college they teached this kind of queries.... now what kind of queries i have to use in project for safety.... if u suggest i will start to learn.... if u dont mind can u tell.. what i have to do....? to develop secured PROJECT(application)..."

C#

UGIcon.Open();
cmd = new SqlCommand("UPDATE purchase SET om=@OM, address=@AD, phone=@PH, baled=@BE, paid=@PD, status=@ST, balance=@BL where cm=@CM", UGIcon);
cmd.Parameters.AddWithValue("@OM", textBox2.Text);
cmd.Parameters.AddWithValue("@AD", textBox3.Text);
cmd.Parameters.AddWithValue("@PH", maskedTextBox1.Text);
cmd.Parameters.AddWithValue("@BE", numericUpDown2.Value);
cmd.Parameters.AddWithValue("@PD", textBox9.Text);
cmd.Parameters.AddWithValue("@ST", textBox4.Text);
cmd.Parameters.AddWithValue("@BL", textBox10.Text);
cmd.Parameters.AddWithValue("@CM", toolStripTextBox1.Text);
int updated = cmd.ExecuteNonQuery();
if (updated == 0)
   {
   MessageBox.Show("No records were updated");
   }
else
   {
   MessageBox.Show("Details has been updated sucessfully", "Update Window", MessageBoxButtons.OK, MessageBoxIcon.Information);
   }
UGIcon.Close();

Depending on the values in your tables, you should check and convert your values to the appropriate datatypes (to prevent the user typing an alpha into a numeric field, and so on - but you should check all that at the top of your method anyway and not get this far if there is a problem.)

If your college doesn't teach you about SQL injection attacks, then you have a pretty poor lecturer. (And I would not suggest that you try to see what happens if you try one on his code - you might get expelled if you "accidentally" delete his tables...)