how to open a message box

Question

i m writing the code:

string query = "Select * from AdminLogin where username='" + name + 
               "' and password='" +   password + "'";

DataSet ds = BusinessLogic.returnDataSet(query);
foreach (DataRow dr in ds.Tables[0].Rows)
{
    if (dr[0].ToString() == name && dr[1].ToString() == password)
    {
      Response.Redirect("~/Home.aspx");
    }
    else
    {
      //Here I want to write the code that will open a message box 
      //that will tell to user that username and password does not match.
     }
}

Define "message box"? This looks like a website, so do you want a JavaScript `alert()`, text in a `
` element, or what? — Widor, Aug 09 '12 at 11:22
Well you haven't actually asked how to call JavaScript yet anyway... — Widor, Aug 09 '12 at 11:25
Sidenote: Beware of [Bobby Tables](http://bobby-tables.com/)! — Heinzi, Aug 09 '12 at 11:25
@Heinzi No SO question with SQL Injection vulnerabilities is complete without a bobby tables link :) — Curt, Aug 09 '12 at 11:28

Curt · Accepted Answer · 2012-08-09T11:42:26.773

1

By message box I'm assuming you mean a javascript alert. I'm not a big fan of posting back with javascript functions. I think its messy, and that javascript should only be used when dealing with client-side actions.

I would actually recommend to use a placeholder and a literal control for this. You could have the following in your webform:

<asp:placeholder id="phLoginFailed" runat="server" visible="false">
     <div class="loginfailed">
        Login failed
     </div>
</asp:placeholder>

This placeholder could be styled like a popup, or displayed within your page using CSS.

Then change your C# to:

else
{
    phLoginFailed.Visible = true;
}

Also, its worth mentioning, your SQL query is prone to SQL Injection. You should use parameterised queries.

And you should encrypt passwords when storing them in the database for security purposes.

edited Aug 09 '12 at 11:42

answered Aug 09 '12 at 11:24

Curt

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And you shouldn't be storing plain text passwords. Hash them first & compare the hashed values – Simon Halsey Aug 09 '12 at 11:25
@SimonHalsey You've downvoted me for that? – Curt Aug 09 '12 at 11:26
didn't downvote you. just adding to your very good point about SQL injection. Sorry if that wasn't clear – Simon Halsey Aug 09 '12 at 11:29
@SimonHalsey Sorry, I assumed you -1 because I got a downvote at the same time. I've added your point regarding password encryption :) – Curt Aug 09 '12 at 11:29
@Ankur I need more information than that. What is not working? Are you getting an error – Curt Aug 09 '12 at 11:30
@Ankur And I'll be impressed if you've managed to parametise your queries, style your login failure and improve your password security in the last 6 minutes! – Curt Aug 09 '12 at 11:31
ya thanks...but when i am using placeholder and i have visible it then it is not showing error message on the page. – Ankur Aug 09 '12 at 11:36

score 0 · Answer 2 · answered Aug 09 '12 at 11:24

0

This is not as easy as it sounds. Basically, you have two options:

Send some JavaScript to the client (for example, using RegisterClientScriptBlock) which calls the JavaScript alert(...); method.
Alternatively, use an ASP.NET component that "looks like" a popup. One example is the ModalPopup component in the ASP.NET Ajax Control Toolkit.

answered Aug 09 '12 at 11:24

Heinzi

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can u explain it more...i am not getting what you want to say. – Ankur Aug 09 '12 at 11:39

Pranay Rana · Answer 3 · 2012-08-09T12:46:42.343

0

just write this line where you want o show message

this.Page.RegisterClientScriptBlock(Page.GetType(),"key", "alert('Wrong username or password')",true);

Edited code

 if (dr[0].ToString() == name && dr[1].ToString() == password)
     {
       Response.Redirect("~/Home.aspx");
     }
     else
     {
         this.Page.RegisterClientScriptBlock(Page.GetType(),"key", "alert('Wrong username or password')",true);

       //Here I want to write the code that will open a message box
        //that will tell to user that username and password does not match.
      }

edited Aug 09 '12 at 12:46

answered Aug 09 '12 at 11:25

Pranay Rana

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can u tell me what should i write in key? – Ankur Aug 09 '12 at 11:33
@Ankur -any string value you can wirte there .. – Pranay Rana Aug 09 '12 at 12:45
@Ankur - is that work for you ??????? – Pranay Rana Aug 09 '12 at 15:14
i have write so many code or logic there but none of output is working there..i don't know why it is going with me... – Ankur Aug 10 '12 at 06:00
and of course i will mark the answer when i get the right solution. – Ankur Aug 10 '12 at 06:00

jekcom · Answer 4 · 2012-08-09T11:34:17.560

0

ClientScript.RegisterClientScriptBlock(Page.GetType(),"key", "alert('Wrong username or password')", true);

or if it is used outside page scope then

        Page page = (HttpContext.Current.Handler as Page);
        if (page!=null)
        {
            page.ClientScript.RegisterClientScriptBlock(Page.GetType(), "key", "alert('Wrong username or password')", true);
        }

edited Aug 09 '12 at 11:34

answered Aug 09 '12 at 11:29

jekcom

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how to open a message box

4 Answers4