Silverlight Siverlight 4中的无极加载屏幕

在编译和运行时，当我尝试在Google Chrome或Mozilla Firefox中加载页面时，它只显示蓝色的进度，并在一瞬间显示一个百分比，然后消失

整个登录页的代码

public partial class LoginPage : UserControl
    {
        public bool UsernameExists = false;
        public bool PasswordExists = false;
        public bool SchoolExists = false;
        public LoginPage()
        {
            InitializeComponent();
        }

        private void username_autocompletebox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            //Checks if user entered all neccessary values, enables Login_button if so
            if (username_autocompletebox.Text.Length != 0)
            {
                UsernameExists = true;
            }
            else
            {
                UsernameExists = false;
            }
            if (UsernameExists = true && PasswordExists == true && SchoolExists == true)
            {
                Login_button.IsEnabled = true;
            }
            else
            {
                Login_button.IsEnabled = false;
            }
        }

        private void password_passwordbox_PasswordChanged(object sender, RoutedEventArgs e)
        {
            //Checks if user entered all neccessary values, enables Login_button if so
            if (password_passwordbox.Password.Length != 0)
            {
                PasswordExists = true;
            }
            else
            {
                PasswordExists = false;
            }
            if (UsernameExists = true && PasswordExists == true && SchoolExists == true)
            {
                Login_button.IsEnabled = true;
            }
            else
            {
                Login_button.IsEnabled = false;
            }
        }

        private void school_combobox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            //Checks if user entered all neccessary values, enables Login_button if so
            if (school_combobox.SelectedItem != null && school_combobox.SelectedItem.ToString() != "Select a School")
            {
                SchoolExists = true;
            }
            else
            {
                SchoolExists = false;
            }
            if (UsernameExists = true && PasswordExists == true && SchoolExists == true)
            {
                Login_button.IsEnabled = true;
            }
            else
            {
                Login_button.IsEnabled = false;
            }
        }

        private void Login_button_Click(object sender, RoutedEventArgs e)
        {
            Authenticate Authenticator = new Authenticate();
            User CurrentUser = Authenticator.Login(username_autocompletebox.Text, password_passwordbox.Password, school_combobox.SelectedItem.ToString());
        }
    }

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很可能是未处理的异常正在

应用程序\u UnHandledException

中处理。在

应用程序\u UnHandledException

处理程序处放置断点以查看问题，或在抛出未处理异常时在VS中放置断点。您还可以在浏览器中找到stacktrace以查看问题。这通常发生在XAML不正确的地方。引用可能不存在的事件处理程序或样式等