Question

之前似乎有这个工作，只是为我的应用程序创建一个登录系统。让它检查用户的本地数据库并使用用户信息创建对象。但是当用户登录登录窗口时，应该关闭并显示主窗口。

当发生这种情况时，我需要从登录窗口访问数据，如下所示：

protected override void OnStartup(System.Windows.StartupEventArgs e)
        {
            if (!AreSettingsSet())
            {
                Window LoginWindow = new Views.LoginWindow();
                LoginWindow.ShowDialog(); 
                //Waits until closed.

                //If the login form was closed properly, handle the user
                if (LoginWindow.DialogResult == true)
                {
                    MessageBox.Show("Logged in correctly!");
                    //Add the user to the list of logged users
                    User returned = LoginWindow.returnUser;
                    MessageBox.Show("First name:" + returned.FirstName);
                    LoggedUsers.Add(returned);
                }
                else
                {
                    //Unexpected window close, possible Alt + F4, shutdown!
                    MessageBox.Show(Messages.UnexpectedClose);
                    this.Shutdown();
                }

                // Recheck the settings now that the login screen has been closed.
                if (!AreSettingsSet())
                {

                }
            }

            this.MainWindow = new Views.Main();
            this.MainWindow.Show();
        }

这是LoginWindow：

//Give App access to user object outside of this form
        public User returnUser
        {
            get
            {
                return user;
            }
        }

        //Public user object, start empty
        User user = new User();

        //Check the login
        private void doLogin(string email, string password)
        {
            //Connect to database
            using (SqlConnection myConnection = new SqlConnection(Settings.ConnectionString))
            {
                //Try and open the connection
                try
                {
                    myConnection.Open();
                }
                catch (Exception)
                {
                    //Unable to connect to database, just return
                    MessageBox.Show(Messages.UnableOpenConnection);
                    return;
                }

                string salt = null;
                bool found = false;

                using (SqlCommand command = new SqlCommand(Queries.GetSalt, myConnection))
                {
                    //Fetch the salt for the entered email address
                    command.Parameters.Add(new SqlParameter("@email", email));
                    SqlDataReader reader = command.ExecuteReader();

                    //Read the data
                    reader.Read();
                    if (reader.HasRows)
                    {
                        salt = reader["salt"].ToString();
                        found = true;
                    }
                    //Close the reader
                    reader.Close();
                }
                if (found == true)
                {
                    if (salt.Length == 32)
                    {
                        using (SqlCommand command = new SqlCommand(Queries.GetSingleUser, myConnection))
                        {
                            //Salt the password
                            string saltedPassword = Encryption.sha256(password + salt);

                            //Add paramaters
                            command.Parameters.Add(new SqlParameter("@email", email));
                            command.Parameters.Add(new SqlParameter("@password", saltedPassword));

                            SqlDataReader reader = command.ExecuteReader();
                            reader.Read();
                            if (reader.HasRows)
                            {
                                //Populate the login instance
                                user.ID = Convert.ToDecimal(reader["id"]);
                                user.FirstName = reader["firstname"].ToString();
                                user.LastName = reader["lastname"].ToString();
                                user.Email = reader["email"].ToString();
                                user.Permissions = Convert.ToInt16(reader["permissions"]);

                                //Close the reader
                                reader.Close();

                                //See if user has a thumbnail picture and save it's location
                                string thumbLoc = Directory.GetCurrentDirectory() +
                                    "\\Users\\DisplayPictures\\" +
                                    user.FirstName + user.LastName + ".png";

                                if (File.Exists(@thumbLoc))
                                {
                                    user.ThumbLoc = thumbLoc;
                                }
                                else
                                {
                                    user.ThumbLoc = Directory.GetCurrentDirectory() + "\\Users\\DisplayPictures\\user.png";
                                }

                                //Found user and created object, close this window safley
                                this.DialogResult = true;
                                this.Close();
                            }
                            else
                            {
                                //Unable to find a user
                                MessageBox.Show(Messages.NoUserFound);
                                return;
                            }
                        }
                    }
                    else
                    {
                        //Salt is the incorrect length
                        MessageBox.Show(Messages.InvalidSalt);
                        return;
                    }
                }
                else
                {
                    MessageBox.Show(Messages.NoUserFound);
                }
            }
        }

我在这里收到错误User returned = LoginWindow.returnUser;说：

＆＃39; System.Windows.Window＆＃39;不包含＆lt; returnUser＆＃39;的定义并且没有任何扩展方法＆return;用户＆＃39;接受第一个论点键入System.Windows.Window＆＃39;可以找到（你错过了使用指令或程序集引用？）

请帮我解决此问题，如果我发现登录错误，请提出更改建议！

Answer 1

那是因为您声明了LoginWindow类型的Window变量，而不是LoginWindow。 LoginWindow具有returnUser属性，但Window没有。Views.LoginWindow loginWindow = new Views.LoginWindow();。将声明更改为：

var loginWindow = new Views.LoginWindow();

或只是

camelCase

顺便说一句，C＃中的约定是在PascalCase中命名局部变量，而不是PascalCase。对于类型和公共成员（方法，属性等），您应该使用LoginWindow。因此，loginWindow变量应命名为returnUser，ReturnUser属性应为{{1}}。

WPF：在app.xaml.cs中获取关闭窗口结果

1 个答案: