Question

I am trying to create a simple login in page for an WPF app. I am using the following XML file:

<?xml version="1.0" encoding="utf-8"?>
<users>
<user>
<username>test1</username>
<password>1test</password>
</user>
</users>

I am new to LINQ and don’t really understand how to get anything out or assign the results to a variable.

Right now I have:

        XDocument users = new XDocument("users.xml");

        var queryResults =
            from u in users.Root.Descendants("user")
            where u.Element("username").Value == tbUserName.Text && u.Element("password").Value == pbPassword.Password
            select u;

        foreach (var item in queryResult)
        {
            Console.WriteLine(item);
        }

So if my query is right it will write the username and password to the console, if the login values exist in the xml file. This is as much as I understand. I don’t know what to do next to verify or validate the user login. Any help or ideas would be great.

Answer 1

If queryResults is not empty, then the username and password are correct, so you can do it like this:

if (queryResults.Any())
{
    // log user in, let him continue
}
else
{
    // user name or password is incorrect, let the user know and possibly try again
}