Question

I used linq to sql many times its work correctly but today something wrong

this is code which must select password from users table.
I call this method tell wright… result is not password please see picture.

public void GetPassword(int id) 
    {
        using (HProDataContext db = new HProDataContext())
        {
            _CurrentPassword = (from p in db.users
                                    where p.id == _CurrentID
                                    select p.password).ToString();
        }
    }

this how i use this method

private void btnOK_Click(object sender, RoutedEventArgs e)
    {
        if (listView1.SelectedItems.Count < 1)
        {
            MessageBox.Show("Please Select User");
        }
        else if (listView1.SelectedItems.Count > 1)
        {
            MessageBox.Show("Please Select Only One User");
        }
        else
        {
            _CurrentID = Convert.ToInt32(listView1.SelectedValue);
            GetPassword(_CurrentID);

            if (PasswordBox.Password == _CurrentPassword)
            {
                MessageBox.Show("You r in");
            }
            else
            {
                //MessageBox.Show("Password Is incorrect, please try again");
                MessageBox.Show(_CurrentPassword);
            }

        }

    }

Answer 1

You are missing a SingleOrDefault call or a call to Single, First or FirstOrDefault:

_CurrentPassword = (from p in db.users
                    where p.id == _CurrentID
                    select p.password).Single().ToString();

Explanation: Your query returns an IEnumerable<string> even if there is only one item returned. You first need to get that item, before you can make a sensible call to ToString(). BTW: I think the call to ToString() is not needed, because p.password already should be a string.