登录后使用C＃，使用现有参数重定向到其他表单

Question

我正在尝试将经过身份验证的用户重定向到另一个C＃表单。

使用用户名和密码对用户进行身份验证后，他将被发送到另一种表单。 可悲的是，我无法从旧的form元素访问旧的参数。

这是两个表单元素的屏幕截图：

我的代码如下所示：

表格1：

using MaterialSkin;
using MaterialSkin.Controls;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Helpful
{
    public partial class Form1 : MaterialForm
    {
        public Form1()
        {
            InitializeComponent();

            var materialSkinManager = MaterialSkinManager.Instance;
            materialSkinManager.AddFormToManage(this);
            materialSkinManager.Theme = MaterialSkinManager.Themes.LIGHT;
            materialSkinManager.ColorScheme = new ColorScheme(Primary.BlueGrey800, Primary.BlueGrey900, Primary.BlueGrey500, Accent.LightBlue200, TextShade.WHITE);
        }

        private void materialRaisedButton1_Click(object sender, EventArgs e)
        {
            try
            {
                string username = materialSingleLineTextField1.Text;
                string password = materialSingleLineTextField2.Text;
                database_connector dbConnect = new database_connector();
                bool db_response = dbConnect.user_check(username, password);

                if (db_response == true)
                {
                    MessageBox.Show("User authentificated.");
                    new Form2().Show();
                    this.Hide();
                }
                else
                {
                    MessageBox.Show("Please try again, wrong user credentials.");
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
    }
}

表格2：

using MaterialSkin;
using MaterialSkin.Controls;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Helpful
{
    public partial class Form2 : MaterialForm
    {
        public Form2()
        {
            InitializeComponent();

            var materialSkinManager = MaterialSkinManager.Instance;
            materialSkinManager.AddFormToManage(this);
            materialSkinManager.Theme = MaterialSkinManager.Themes.LIGHT;
            materialSkinManager.ColorScheme = new ColorScheme(Primary.BlueGrey800, Primary.BlueGrey900, Primary.BlueGrey500, Accent.LightBlue200, TextShade.WHITE);
        }
    }
}

database_connector类：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using MySql.Data.MySqlClient;

namespace Helpful
{
    class database_connector
    {
        private MySqlConnection connection;
        private string server;
        private string database;
        private string uid;
        private string password;

        // Constructor
        public database_connector()
        {
            Initialize();
        }

        //Initialize values
        private void Initialize()
        {
            server = "xxx";
            database = "xxx";
            uid = "xxx";
            password = "xxx";
            string connectionString;
            connectionString = "SERVER=" + server + ";" + "DATABASE=" +
            database + ";" + "UID=" + uid + ";" + "PASSWORD=" + password + ";";

            connection = new MySqlConnection(connectionString);
        }

        //open connection to database
        private bool OpenConnection()
        {
            try
            {
                connection.Open();
                return true;
            }
            catch (MySqlException ex)
            {
                switch (ex.Number)
                {
                    case 0:
                        MessageBox.Show("Cannot connect to server. Contact administrator.");
                        break;
                    case 1045:
                        MessageBox.Show("Invalid username/password, please try again");
                        break;
                }
                return false;
            }
        }

        //Close connection
        private bool CloseConnection()
        {
            try
            {
                connection.Close();
                return true;
            }
            catch (MySqlException ex)
            {
                MessageBox.Show(ex.Message);
                return false;
            }
        }

        // Select statement
        public bool user_check(string username, string password)
        {
            string query = "SELECT username, password from swear_tool where username='" + username + "' and password = '" + password + "'";

            bool hasRecords = false;

            if (this.OpenConnection() == true)
            {
                MySqlCommand cmd = new MySqlCommand(query, connection);
                MySqlDataReader dataReader = cmd.ExecuteReader();
                if (dataReader.HasRows)
                {
                    while (dataReader.Read())
                    {
                        hasRecords = true;
                    }
                }
                dataReader.Close();
                this.CloseConnection();
            }
            return hasRecords;
        }
    }
}

---

我的问题是，如何在不再次输入用户名的情况下立即使用表单2中的变量用户名？

我将不胜感激。

Answer 1

为了实现所需的功能，必须按照POO和Layers编程进行操作，然后创建一个类来保存数据。

在下面的示例中，您可以在第一个屏幕中设置参数，并且可以从任何其他可以看到此类的表单中访问它：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Models
{
    public class User
    {
        static private string cdUser;
        static private int cdAcess;
        static private string nmUser;

        public static string CdUser
        {
            get
            {
                return cdUser;
            }

            set
            {
                cdUser = value;
            }
        }
        public static int CdAcess
        {
            get
            {
                return cdAcess;
            }

            set
            {
                cdAcess = value;
            }
        }
        public static string NmUser
        {
            get
            {
                return nmUser;
            }

            set
            {
                nmUser = value;
            }
        }
    }
}

要保存数据，您可以执行以下操作：

User.CdUser = _login;
User.CdAcess = Convert.ToInt32(rdr["acess"].ToString());
User.NmUser = rdr["name"].ToString();

Answer 2

为可以很好地获得名称的Form2创建一个构造函数，或者在Form2中创建一个很好地包含它并对其进行设置的字段。

//first approach
new Form2(username).show();
//second approach
var f2 = Form2();
f2.username = username;
f2.show()