如果从datagrid C＃中的文本框中获取值，则增加数量＃ [英] Increment quantity if have value from textbox in datagrid C#

问题描述

Some litle help.
 
Need if  exist in datagrid value from textbox1 ( column name: bar_code) to increment cell kolicina(quantity eng.) + 1

我尝试过：

What I have tried:

private void prijavaAction()  
        {  
  
            int sno = dataGridView1.Rows.Count + 1;  
  
            SqlConnection con = new SqlConnection(cs);  
  
            if (textBox1.Text.All(char.IsDigit))  
  
            {  
                string queryString = "select bar_kod, ime, cijena_sa_porezom from roba_usluge WHERE bar_kod = '" + textBox1.Text + "'";// pronaci artikl u bazi                
                using (SqlConnection connection = new SqlConnection(cs))  
                {  
                    SqlCommand command = new SqlCommand(queryString, connection);  
                    connection.Open();  
                    SqlDataReader reader = command.ExecuteReader();  
  
                     
                    var itemAndPrice = textBox1.Text;  
  
                    if (reader.Read())  
                    {                         
  
                        var index = dataGridView1.Rows.Add();  
                        dataGridView1.Rows[index].Cells["redni_broj"].Value = index + 1;  
                        dataGridView1.Rows[index].Cells["bar_kod"].Value = reader["bar_kod"].ToString();  
                        dataGridView1.Rows[index].Cells["naziv_artikla"].Value = reader["ime"].ToString();  
                        dataGridView1.Rows[index].Cells["cijena"].Value = reader["cijena_sa_porezom"].ToString();  
                        dataGridView1.Rows[index].Cells["kolicina"].Value = "1";  
  
  
                        foreach (DataGridViewRow g1 in dataGridView1.Rows)  
                        {  
  
  
                            g1.Cells["ukupno"].Value = (Convert.ToDouble(g1.Cells["kolicina"].Value) * Convert.ToDouble(g1.Cells["cijena"].Value)).ToString("0.00");  
  
  
  
                                   g1.Cells["kolicina"].Value = Convert.ToInt32(g1.Cells["kolicina"].Value) + 1;  
  
                             
  
                        }  
  
  
                       
  
  
                    }  
                    else  
                    {  
                        MessageBox.Show("Bar kod ne postoji u bazi!", "Obavještenje", MessageBoxButtons.OK, MessageBoxIcon.Information);  
                        textBox1.Text = "";  
                    }  
  
                    
                }  
  
            }  
  
            else  
            {  
                MessageBox.Show("Bar kod ne postoji ili nije bar kod!", "Obavještenje", MessageBoxButtons.OK, MessageBoxIcon.Information);  
                textBox1.Text = "";  
            }  
  
}  

推荐答案

不要这样做！永远不要连接字符串来构建SQL命令。它让您对意外或故意的SQL注入攻击持开放态度，这可能会破坏您的整个数据库。总是使用参数化查询。



连接字符串时会导致问题，因为SQL会收到如下命令：

Don't do it like that! Never 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. Always use Parameterized queries instead.

When you concatenate strings, you cause problems because SQL receives commands like:

SELECT * FROM MyTable WHERE StreetAddress = 'Baker's Wood'

就SQL而言，用户添加的引号会终止字符串，并且您会遇到问题。但情况可能更糟。如果我来并改为输入：x'; DROP TABLE MyTable; - 然后SQL收到一个非常不同的命令：

The quote the user added terminates the string as far as SQL is concerned and you get problems. But it could be worse. If I come along and type this instead: "x';DROP TABLE MyTable;--" Then SQL receives a very different command:

SELECT * FROM MyTable WHERE StreetAddress = 'x';DROP TABLE MyTable;--'

哪个SQL看作三个单独的命令：

Which SQL sees as three separate commands:

SELECT * FROM MyTable WHERE StreetAddress = 'x';

完全有效的SELECT

A perfectly valid SELECT

DROP TABLE MyTable;

完全有效的删除表格通讯和

A perfectly valid "delete the table" command

--'

其他一切都是评论。

所以它确实：选择任何匹配的行，从数据库中删除表，并忽略其他任何内容。



所以总是使用参数化查询！或者准备好经常从备份中恢复数据库。你经常定期备份，不是吗？



现在浏览整个应用程序并确保每次访问数据库时都修复。想念一个，......

And everything else is a comment.
So it does: selects any matching rows, deletes the table from the DB, and ignores anything else.

So ALWAYS use parameterized queries! Or be prepared to restore your DB from backup frequently. You do take backups regularly, don't you?

Now go through your whole app and make sure you fix every time you access the DB. Miss one, and ...

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