title: How can I pass data between windows in my C# WPF application?
body: <p>I have a login form in the MainWindow of my WPF application.  If the user logs in successfully, I want to open the HomeWindow.  My problem is that I need to pass the adminID variable from the MainWindow to the HomeWindow.  How can I do this?</p>
  
  <pre><code>public partial class MainWindow : Window
          {
              public MainWindow()
              {
                  InitializeComponent();
              }
  
              private void btnLogin_Click(object sender, RoutedEventArgs e)
              {
                  int errors = 0;
                  if (txtUsername.Text == "")
                  {
                      lblUsernameStatus.Content = "This field is required.";
                      errors = errors + 1;
                  }
  
                  if (txtPassword.Text == "")
                  {
                      lblPasswordStatus.Content = "This field is required.";
                      errors = errors + 1;
                  }
  
                  if (errors == 0)
                  {
                      Administrator TryLogin = new Administrator();
                      if (TryLogin.VerifyUser(txtUsername.Text, txtPassword.Text))
                      {
                          HomeWindow home = new HomeWindow();
                          int adminID = TryLogin.userID;
                          home.Show();
                          this.Close();
                      }
                      else
                      {
                          lblLoginStatus.Content = TryLogin.status;
                      }
  
                  }
              }
  </code></pre>
  
  <p>PS:  I haven't written anything in the HomeWindow.xaml.cs file.</p>