使用 Mysql 将我的 WPF 项目转换为 MVVM [关闭]

Question

我是 C# 编码的新手，因此我在开始我的项目时犯了一些错误。这意味着我的所有代码都是在表单中完成的（连接到数据库、执行选择语句和即将到来的更新/插入/删除）。其次，我的大部分代码都是重复的。如代码所示，我有几种几乎相同的表单（唯一的区别是在不同的表上进行选择）。

这是来自称为字符的形式：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using MySql.Data.MySqlClient;

namespace Dark_Heresy
{
    /// <summary>
    /// Interaction logic for Character.xaml
    /// </summary>
    public partial class Character : Window
    {
        public Character()
        {
            InitializeComponent();
        }

        private void character_name_loader(object sender, RoutedEventArgs e)
        {
            string constring = "datasource= localhost; port=3306; username=root; password=Mypass;";
            string Query = "SELECT Name_ FROM dark_heresy.character_";
            MySqlConnection conDataBase = new MySqlConnection(constring);
            MySqlCommand cmdDatabase = new MySqlCommand(Query, conDataBase);
            MySqlDataReader myReader;

            try
            {
                conDataBase.Open();
                myReader = cmdDatabase.ExecuteReader();

                while (myReader.Read())
                {
                    string charactername = myReader.GetString("Name_");
                    cb_CharacterName.Items.Add(charactername);
                }
            }

            catch (Exception ex)
            {
                MessageBox.Show("Error: \r\n" + ex);
            }
        }

        private void cb_CharacterName_DropDownClosed(object sender, EventArgs e)
        {
            string constring = "datasource = localhost; port = 3306; username = root; password = MyPass;";
            string Query = "SELECT * FROM dark_heresy.character_ WHERE Name_='" + cb_CharacterName.Text + "' ;";
            MySqlConnection conDataBase = new MySqlConnection(constring);
            MySqlCommand cmdDataBase = new MySqlCommand(Query, conDataBase);
            MySqlDataReader myReader;

            try
            {
                conDataBase.Open();
                myReader = cmdDataBase.ExecuteReader();

                while (myReader.Read())
                {
                    string career = myReader.GetString("Class");
                    string world = myReader.GetString("World_Type");
                    string strength = myReader.GetInt32("Str").ToString();
                    string weaponskill = myReader.GetInt32("WS").ToString();
                    string ballisticskill = myReader.GetInt32("BS").ToString();
                    string fellowship = myReader.GetInt32("Fel").ToString();
                    string perception = myReader.GetInt32("Per").ToString();
                    string intelligence = myReader.GetInt32("Int_").ToString();
                    string agility = myReader.GetInt32("Agi").ToString();
                    string willpower = myReader.GetInt32("WP").ToString();
                    string toughness = myReader.GetInt32("Tough").ToString();


                    TextCareer.Text = career;
                    TextWorld.Text = world;
                    TextStrength.Text = strength;
                    TextWeaponskill.Text = weaponskill;
                    TextBallisticskill.Text = ballisticskill;
                    TextFellowship.Text = fellowship;
                    TextPerception.Text = perception;
                    TextIntelligence.Text = intelligence;
                    TextAgility.Text = agility;
                    TextWillpower.Text = willpower;
                    TextToughness.Text = toughness;

                }
            }

            catch (Exception ex)
            {
                MessageBox.Show("Error: \r\n" + ex);
            }
        }

        private void cb_Talent_NameDropDownOpen(object sender, EventArgs e)
        {
            string constring = "datasource= localhost; port=3306; username=root; password=MyPass;";
            string Query = "SELECT Talent_Name FROM dark_heresy.learned_talents WHERE Character_Name='" + cb_CharacterName.Text + "' ;";
            MySqlConnection conDataBase = new MySqlConnection(constring);
            MySqlCommand cmdDatabase = new MySqlCommand(Query, conDataBase);
            MySqlDataReader myReader;

            try
            {
                conDataBase.Open();
                myReader = cmdDatabase.ExecuteReader();

                while (myReader.Read())
                {
                    string talent_name = myReader.GetString("Talent_Name");
                    Talent_Name.Items.Add(talent_name);
                }
            }

            catch (Exception ex)
            {
                MessageBox.Show("Error: \r\n" + ex);
            }
        }

        private void cb_Talent_Name_DropDownClosed(object sender, EventArgs e)
        {
            string constring = "datasource = localhost; port = 3306; username = root; password = MyPass;";
            string Query = "SElECT learned_talents.Talent_Name , talents.Description FROM dark_heresy.learned_talents, dark_heresy.talents WHERE learned_talents.Talent_Name = talents.TalentName AND learned_talents.Character_Name = '" + cb_CharacterName.Text + "';";
            MySqlConnection conDataBase = new MySqlConnection(constring);
            MySqlCommand cmdDataBase = new MySqlCommand(Query, conDataBase);
            MySqlDataReader myReader;

            try
            {
                conDataBase.Open();
                myReader = cmdDataBase.ExecuteReader();

                Talent_Name.Items.Clear();

                while (myReader.Read())
                {
                    string talents_description = myReader.GetString("Description");

                    Talents_Description.Text = talents_description;
                }
            }

            catch (Exception ex)
            {
                MessageBox.Show("Error: \r\n" + ex);
            }
        }

        private void Skill_Name_DropDownOpened(object sender, EventArgs e)
        {
            string constring = "datasource= localhost; port=3306; username=root; password=MyPass;";
            string Query = "SELECT Skill_Name FROM dark_heresy.learned_skills WHERE Character_Name='" + cb_CharacterName.Text + "' ;";
            MySqlConnection conDataBase = new MySqlConnection(constring);
            MySqlCommand cmdDatabase = new MySqlCommand(Query, conDataBase);
            MySqlDataReader myReader;

            try
            {
                conDataBase.Open();
                myReader = cmdDatabase.ExecuteReader();

                while (myReader.Read())
                {
                    string skill_name = myReader.GetString("Skill_Name");
                    Skill_Name.Items.Add(skill_name);
                }
            }

            catch (Exception ex)
            {
                MessageBox.Show("Error: \r\n" + ex);
            }

        }

        private void Skill_Name_DropDownClosed(object sender, EventArgs e)
        {
            string constring = "datasource = localhost; port = 3306; username = root; password = MyPass;";
            string Query = "SElECT learned_skills.Skill_Name , skills.Descriptor FROM dark_heresy.learned_skills, dark_heresy.skills WHERE learned_skills.Skill_Name = skills.SkillName AND learned_skills.Character_Name = '" + cb_CharacterName.Text + "';";
            MySqlConnection conDataBase = new MySqlConnection(constring);
            MySqlCommand cmdDataBase = new MySqlCommand(Query, conDataBase);
            MySqlDataReader myReader;

            try
            {
                conDataBase.Open();
                myReader = cmdDataBase.ExecuteReader();

                Skill_Name.Items.Clear();

                while (myReader.Read())
                {
                    string skills_description = myReader.GetString("Descriptor");

                    Skill_Description.Text = skills_description;
                }
            }

            catch (Exception ex)
            {
                MessageBox.Show("Error: \r\n" + ex);
            }

        }



    }
}

一种叫做天赋的形式：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using MySql.Data.MySqlClient;

namespace Dark_Heresy
{
    /// <summary>
    /// Interaction logic for Talents.xaml
    /// </summary>
    public partial class Talents : Window
    {
        public Talents()
        {
            InitializeComponent();
        }

        private void cb_loader(object sender, RoutedEventArgs e)
        {
            string constring = "datasource= localhost; port=3306; username=root; password=MyPass;";
            string Query = "SELECT TalentName FROM dark_heresy.talents";
            MySqlConnection conDataBase = new MySqlConnection(constring);
            MySqlCommand cmdDatabase = new MySqlCommand(Query, conDataBase);
            MySqlDataReader myReader;

            try
            {
                conDataBase.Open();
                myReader = cmdDatabase.ExecuteReader();

                while (myReader.Read())
                {
                    string talentname = myReader.GetString("TalentName");
                    cb_Talents.Items.Add(talentname);
                }
            }

            catch (Exception ex)
            {
                MessageBox.Show("Error: \r\n" + ex);
            }

        }

        private void cb_Talent_DropDownClosed_(object sender, EventArgs e)
        {
            string constring = "datasource = localhost; port = 3306; username = root; password = MyPass;";
            string Query = "SELECT * FROM dark_heresy.talents WHERE TalentName='" + cb_Talents.Text + "' ;";
            MySqlConnection conDataBase = new MySqlConnection(constring);
            MySqlCommand cmdDataBase = new MySqlCommand(Query, conDataBase);
            MySqlDataReader myReader;

            try
            {
                conDataBase.Open();
                myReader = cmdDataBase.ExecuteReader();

                while (myReader.Read())
                {

                    string description = myReader.GetString("Description");
                    string strength = myReader.GetInt32("R_Str").ToString();
                    string weaponskill = myReader.GetInt32("R_WS").ToString();
                    string ballisticskill = myReader.GetInt32("R_BS").ToString();
                    string fellowship = myReader.GetInt32("R_Fel").ToString();
                    string perception = myReader.GetInt32("R_Per").ToString();
                    string intelligence = myReader.GetInt32("R_Int").ToString();
                    string agility = myReader.GetInt32("R_Agi").ToString();
                    string willpower = myReader.GetInt32("R_WP").ToString();
                    string toughness = myReader.GetInt32("R_Tough").ToString();


                    TextDescription.Text = description;
                    TextStrength.Text = strength;
                    TextWeaponskill.Text = weaponskill;
                    TextBallisticskill.Text = ballisticskill;
                    TextFellowship.Text = fellowship;
                    TextPerception.Text = perception;
                    TextIntelligence.Text = intelligence;
                    TextAgility.Text = agility;
                    TextWillpower.Text = willpower;
                    TextToughness.Text = toughness;



                }
            }

            catch (Exception ex)
            {
                MessageBox.Show("Error: \r\n" + ex);
            }
        }
    }
}

我发现我需要在我的项目中做一些业务逻辑。这导致我使用 MVVM，这意味着我的项目完全错误。

目前我唯一的参考是mysql.dll

我已经阅读/看过关于 MVVM 的教程，但是我有一些问题。

1. 如果我使用 MVVM 模式，我与 SELECT/UPDATE/INSERT/DELETE 的数据库连接是否会存储在 ViewModel（业务逻辑）中？还是会成为模型的一部分？

2. 谁能向我解释如何更改当前代码，以便将其从模型使用到 ViewModel 再到 View？如果可能的话，举个例子。

3. Model、ViewModel 应该采用什么形式？ WPF、接口、类、类库等

4. 有没有人有一些有用的链接可以帮助我解决这个问题，特别是当它与作为本地主机的 MySQL 数据库结合使用时。

Answer 1

我会按顺序解决你的问题：

1. 不，它们会在模型中。考虑将与数据库相关的所有内容都移到它自己的层中 - 我建议您查看一种名为 Repository 的模式及其工作原理（通过接口将存储实现与底层存储技术分离）。
2. 您需要做出判断，因为您知道代码在做什么。我建议你阅读关于构建应用程序的 Prism 库文档，特别是关于模块化应用程序开发的第 4 节——这应该让你对实际应用程序的结构有了一个很好的开端。不要担心特定于 Prism 的细节，看看 Views、ViewModels 和 Repositories 如何被隔离到功能区域中。 http://msdn.microsoft.com/en-us/library/gg405479(v=pandp.40).aspx
3. View 是 WPF XAML，ViewModel 和 Model 通常应该是 C# 类。
4. 有关 Prism 库文档，请参见上面的内嵌文本。

即使您不执行完整的 Module Bootstrap Composite Application 路线，Prism 也可以作为一组类库很好地作为 MVVM 框架的基础参考。那里有很多课程利用 WPF 开发的最佳实践。对于新手来说，这是一个很好的信息来源，但需要时间来理解这些概念。

更新：“你会将 MVVM 与存储库结合起来吗？”

好的，在典型的商业编程中，您将应用程序构建为 3 个不同的逻辑层 - 表示、业务逻辑和数据。存储库通常位于应用程序的数据层中。业务逻辑通常封装大部分“真实”业务逻辑所在的服务层（从 MVVM 的角度来看，它会被视为模型的一部分）。 Presentation 是 MVVM 所在的位置，特别是 VM 和 Views。

每一层都将保留/访问对下一层中对象的引用，即 VM 将引用模型/业务逻辑层，业务逻辑将引用数据/存储库层。 VM 通常不会直接引用数据层，因为这会破坏分层架构并可能导致复杂化。

在某些情况下（混合技术，例如业务逻辑层的 TIBCO 服务），您甚至不会在应用程序的所有层上工作，而只会在一个层上工作。这就是 DB 专家开发人员的用武之地，例如，尤其是在需要专门查询以满足数据仓库系统的性能要求的高性能系统中。