how to open a message box [closed] - asp.net

Question

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Closed 10 years ago.
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.
}
}

Answer 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.

Answer 2

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.

Answer 3

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);
}

Answer 4

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.
}