title: Visual Basic 2010 Express: Check if my.settings.username has a value
body: <p>VISUAL BASIC: You know how you can make your own settings in your program <em>setting/properties</em>, well I made a register system for a software. You register by entering a password and username then pressing 'Register' to save the username and password to My.Settings.Username and My.Settings.Password using My.Settings.Save().</p>
  
  <p><strong>The code:</strong> <code>My.Settings.Username = TextBox1.Text
    My.Settings.Password = TextBox2.Text
    My.Settings.Save()</code>
  This all works perfectly but how can I prevent the user from changing it again.</p>
  
  <p><strong>This is my code so far:</strong></p>
  
  <pre><code>Private Sub Button6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button6.Click
      Dim res As MsgBoxResult
      If Not My.Settings.Username = String.Empty And
         My.Settings.Password = String.Empty Then
          MsgBox("You have registered a WCUE account, please use 'CHANGE PASSWORD' in 'Settings' to do so.", MsgBoxStyle.Exclamation, "Not possible.")
      ElseIf TextBox1.Text = String.Empty Or
          TextBox2.Text = String.Empty Then
          MsgBox("Don't press the register button if the text boxes are empty!", MsgBoxStyle.Critical, "Fill all required fields please.")
      Else
          If TextBox1.Text = My.Settings.Username And
              TextBox2.Text = My.Settings.Password Then
              MsgBox("If you are trying to log in then press the 'Log-in' text below the register button!", MsgBoxStyle.Exclamation, "You have already registered!")
          Else
              res = MsgBox("Register a WCUE account?", MsgBoxStyle.YesNo, "Create")
              If res = MsgBoxResult.Yes Then
                  My.Settings.Username = TextBox1.Text
                  My.Settings.Password = TextBox2.Text
                  My.Settings.Save()
                  MsgBox("You can now login to WCUE and set the time limit on this user!", MsgBoxStyle.Information, "YEAH - Register successful!")
              ElseIf res = MsgBoxResult.No Then
                  MsgBox("You should register as quick as possible before someone unauthorized sets a password!!", MsgBoxStyle.Exclamation, "Suit yourself.")
              End If
          End If
          Exit Sub
      End If
  End Sub
  </code></pre>
  
  <p>The FIRST if statement is what I am having trouble with, I tried to check if My.Settings.Username and My.Setting.Password contains a value (string) which should be the username and password, if it does not then you can register but if it does contain a value then it tells you that someone has already registered. Nothing happens?
  <em>I hope this is clear enough, please help!</em></p>