How to check the user name availability while typing the UserName in the TextBox in C#, ASP.Net?

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1.00/5 (1 vote)

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SQL-Server-2005

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Hi friends,
I'm new to C#, ASP.Net. Now i'am trying to work on create new account module. I don't know how to validate the "User ID" while typing in the text box field.

It means when user enter the username.If already exist this userid in database then message show this userid already exist.

Posted 14-Feb-13 5:43am

mn.sathish

Updated 14-Feb-13 6:25am

v3

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Richard C Bishop 14-Feb-13 11:45am

This is not a question nor does it provide any information that anyone could deduce a helpful response to. Use the "Improve question" widget to elaborate on your issue and provide code that you have attempted already. Also, ask a specific question on where you are stuck.

3 solutions

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Taha Akhtar · Answer 1 · 2013-02-14T09:17:00

Solution 5

use page method for validation for username

http://blogs.microsoft.co.il/blogs/gilf/archive/2008/10/04/asp-net-ajax-pagemethods.aspx[^]

Posted 14-Feb-13 9:17am

Taha Akhtar

Espen Harlinn · Answer 2 · 2013-02-14T06:30:00

Solution 3

Have a look at:
ASP.NET Authentication[^]
ASP.NET Authorization[^]
ASP.NET Impersonation[^]

There is also a user interface component that is provided with .Net for this purpose:
Login Class[^]

If you're new to ASP.Net, this isn't the best place to start, as it may open your system to all sorts of nastiness ...

Have a look at Exploits of a Mom[^] - it's a nice example :-D

Best regards
Espen Harlinn

Posted 14-Feb-13 6:30am

Espen Harlinn

Updated 14-Feb-13 6:37am

v2

Comments

fjdiewornncalwe 14-Feb-13 13:15pm

+5. Love the xkcd part.

Espen Harlinn 14-Feb-13 13:16pm

Thank you, Marcus :-D

Sergey Alexandrovich Kryukov 14-Feb-13 14:20pm

Too fine reply to this non-question. My 5. I would probably not answer, did not get enough patience. :-)
—SA

Sergey Alexandrovich Kryukov 14-Feb-13 14:24pm

Oh, Exploits of a Mom is a fine example of SQL Injection. Another 5! Use parametrized queries!
If you don't mind, shall I use it next time I see a need to explain this exploit? :-)
—SA

Espen Harlinn 14-Feb-13 14:46pm

Thanks Sergey, I don't mind at all - and I guess It's been posted in the lounge a couple of times too :-D

Sergey Alexandrovich Kryukov 14-Feb-13 14:53pm

Thank you. :-)
By the way, I look at other comics at the side, did not find any interesting...
—SA

Espen Harlinn 14-Feb-13 15:14pm

Ohh, what about:
http://www.xkcd.com/303/
http://www.xkcd.com/138/

Sergey Alexandrovich Kryukov 14-Feb-13 15:21pm

Well... compiling... :-)
—SA

Espen Harlinn 14-Feb-13 15:34pm

But these days you'll have to have one heck of a codebase, and some very convoluted #includes before you'll notice - but I do remember waiting several hours for stuff to finish compiling - but that was in another millenium

Sergey Alexandrovich Kryukov 14-Feb-13 15:47pm

Not with Turbo/Borland Pascal :-) It was a great choice, in terms of build performance, too.
—SA

Espen Harlinn 14-Feb-13 15:52pm

It certainly was, and Delphi performed likewise.

Sergey Alexandrovich Kryukov 14-Feb-13 16:20pm

Delphi was an epic win, and still is. Too bad the language was not standardized. "ANSI Pascal" is nothing...
—SA

Espen Harlinn 14-Feb-13 16:22pm

I think Embarcadero is heading in the right direction, but repairing the damage done during the last years under Borland ownership will take time.

Sergey Alexandrovich Kryukov 14-Feb-13 16:27pm

Agree. It is very unfortunate that the line Algol -> Pascal -> Borland Pascal / Ada was considerably suppressed. This line is more clear, more academic and better based, etc...
—SA

Avik Ghosh22 · Answer 3 · 2013-02-14T06:02:00

protected void Button1_Click(object sender, EventArgs e)
    {
         using (SqlConnection con = new SqlConnection("----"))
        {
            con.Open();
            SqlCommand cmd = new SqlCommand("Select * FROM TEST WHERE ID='"+TextBox1.Text+"'", con);
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataTable DT = new DataTable();
            da.Fill(DT);
            con.Close();
            if (DT.Rows.Count > 0)
            {
                Response.Write("ALREADY HAVE");
            }
            else
            {
                //YOUR CODE//
            }
            
        }
    }

[Update]
other wise u can use autocomplete textbox ..

http://www.aspdotnet-suresh.com/2012/08/using-jquery-autocomplete-with-aspnet.html[^]

Auto complete Textbox in asp.net using ajax and c#[^]

[Update]

XML

<body>
    <form id="form1" runat="server">
    <div>
        <asp:TextBox ID="TextBox1" runat="server" AutoPostBack="True"
            ontextchanged="TextBox1_TextChanged"></asp:TextBox>
    </div>
    </form>
</body>

----------------------------

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
using System.Data;

public partial class Default2 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void TextBox1_TextChanged(object sender, EventArgs e)
    {
        using (SqlConnection con = new SqlConnection("----"))
        {
            con.Open();
            SqlCommand cmd = new SqlCommand("Select * FROM TEST WHERE ID='" + TextBox1.Text + "'", con);
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataTable DT = new DataTable();
            da.Fill(DT);
            con.Close();
            if (DT.Rows.Count > 0)
            {
                Response.Write("ALREADY HAVE");
            }
            else
            {
                //YOUR CODE//
            }

        }
    }
}