need help with TextBox_TextChanged event

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hello,
i have a textbox and a listbox in my web form ASP.net , what i want is whene i start typing an id on my textbox , the listbox get full of suggestions with ids from my database table that start with the numbers i'm typing
i want only existing ids from database table to appear in listbox
i tried this bau it is not working,the listbox is empty , please help

C#

protected void TextBox1_TextChanged(object sender, EventArgs e)
        {
    SqlCommand cmd = new SqlCommand("select num from navire where num = '"+TextBox1.Text+"%'", connect);
             cmd.ExecuteNonQuery();
            SqlDataReader reader = cmd.ExecuteReader();
            // ListBox1.Items.Clear();
            if (reader.HasRows)
            {
                while (reader.Read())
                {
                    ListBox1.Items.Add(reader.GetString(0).ToString());
                   
                   
                }
            }
        }

Posted 29-Mar-14 2:40am

Member 10656162

Updated 29-Mar-14 3:23am

Christian Amado

v3

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3 solutions

Solution 2

You really, really, don't want to be doing that!

Think about it: each time your user types a key, a postback has to occur to the server, the server has to create the page, handle the text change, access the database, wait for the response, format it to HTML and send it back to the client. Me, as a user I would have got bored and gone elsewhere by about the third keypress...
Do it in the client! Javascript should be able to handle it: http://www.c-sharpcorner.com/UploadFile/5089e0/how-to-show-textbox-value-exit-in-database-using-javascript/[^] does some of the work.

Posted 29-Mar-14 2:53am

OriginalGriff

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Ankur Ramanuj · Accepted Answer · 2014-03-29T02:50:00

Solution 1

if you only display id as a suggestion than try something like this
http://www.asp.net/ajaxlibrary/ajaxcontroltoolkitsamplesite/autocomplete/autocomplete.aspx

Posted 29-Mar-14 2:50am

Ankur Ramanuj

Krunal Rohit · Accepted Answer · 2014-03-29T09:02:00

Solution 3

Why.. Why.. Why anyone would do such thing?? It's a bad practice. (Performance issue)

Rather I'd say use AutoComplete Textbox.
See the examples,
AutoComplete With DataBase and AjaxControlToolkit[^]
AutoComplete With DataBase and AjaxControlToolkit[^]
http://www.aspdotnet-suresh.com/2012/08/using-jquery-autocomplete-with-aspnet.html[^]

-KR

Posted 29-Mar-14 9:02am

Krunal Rohit

Comments

Member 10656162 29-Mar-14 20:24pm

:) i want to thank you for your solution , my problem is solved
i followed this exemple
http://www.dotnetfox.com/articles/ajax-autocomplete-example-with-database-in-Asp-Net-1079.aspx
ps: i'm just a student and a beginner in asp.net and web app so it really seemed a good solution that's why i tried it