基于数据库的vs2019的T4模版代码生成器（二）基于mysql数据库

总体介绍

参考文档：

https://www.cnblogs.com/laozhang-is-phi/p/9757999.html

只想用 ADO.NET 搭建多层框架，动软代码生成器是一个不错的选择。

T4 (Text Template Transformation Toolkit) 是微软官方在 VisualStudio 2008+ 中开始使用的代码生成引擎。在 Visual Studio 中，“T4 文本模板”是由一些文本块和控制逻辑组成的混合模板，它可以生成文本文件。 在 Visual C# 或 Visual Basic 中，控制逻辑编写为程序代码的片段。生成的文件可以是任何类型的文本，例如网页、资源文件或任何语言的程序源代码。现在的VS中只要与代码生成相关的场景基本上都能找T4的身影，比如MVC的视图模板，Entity Framwork的DataContext模板等等。

 这里就不具体讲解 T4 语法了，大家可以自行学习，其实很简单，主要还是 C# 代码，下边你看过之后就能懂了，咱们首先先实现之前留下的一个伏笔 —— 将我们的数据库表利用T4 模板生成实体类，也就是 DbFirst。

1 首先在我们的项目中，新建一个类库 Xwy.Core.FrameWorkT4Mysql 

2 在该类库下，新建文件夹 Xwy.Core.FrameWorkT4Mysql.Entity，用于单独存放我们的模板以及生成的实体类文件

3 ModelAuto.ttinclude 文本文件代码

//引入命名空间
<#@ assembly name="System.Core"#>
<#@ assembly name="EnvDTE"#>
<#@ import namespace="System.Collections.Generic"#>
<#@ import namespace="System.IO"#>
<#@ import namespace="System.Text"#>
<#@ import namespace="Microsoft.VisualStudio.TextTemplating"#>

<#+
//定义管理者 manager 实体类
class Manager
{
    //定义一个 block 块，主要是应用在批量生产中
    public struct Block {
        public String Name;
        public int Start, Length;
    }

    public List<Block> blocks = new List<Block>();
    public Block currentBlock;
    public Block footerBlock = new Block();
    public Block headerBlock = new Block();
    public ITextTemplatingEngineHost host;
    public ManagementStrategy strategy;
    public StringBuilder template;
    public String OutputPath { get; set; }
    //构造函数，包含 host主机，模板，输出路径，创建管理策略
    public Manager(ITextTemplatingEngineHost host, StringBuilder template, bool commonHeader) {
        this.host = host;
        this.template = template;
        OutputPath = String.Empty;
        strategy = ManagementStrategy.Create(host);
    }
    //开辟一个 block 块
    public void StartBlock(String name) {
        currentBlock = new Block { Name = name, Start = template.Length };
    }

    public void StartFooter() {
        footerBlock.Start = template.Length;
    }

    public void EndFooter() {
        footerBlock.Length = template.Length - footerBlock.Start;
    }

    public void StartHeader() {
        headerBlock.Start = template.Length;
    }

    public void EndHeader() {
        headerBlock.Length = template.Length - headerBlock.Start;
    }    

    public void EndBlock() {
        currentBlock.Length = template.Length - currentBlock.Start;
        blocks.Add(currentBlock);
    }
    //定义进程，用来将所有的 blocks 块执行出来
    public void Process(bool split) {
        String header = template.ToString(headerBlock.Start, headerBlock.Length);
        String footer = template.ToString(footerBlock.Start, footerBlock.Length);
        blocks.Reverse();
        foreach(Block block in blocks) {//遍历
            //输出文件
            String fileName = Path.Combine(OutputPath, block.Name);
            if (split) {
                String content = header + template.ToString(block.Start, block.Length) + footer;
                strategy.CreateFile(fileName, content);
                template.Remove(block.Start, block.Length);
            } else {
                strategy.DeleteFile(fileName);
            }
        }
    }
}
//定义管理策略类
class ManagementStrategy
{
    internal static ManagementStrategy Create(ITextTemplatingEngineHost host) {
        return (host is IServiceProvider) ? new VSManagementStrategy(host) : new ManagementStrategy(host);
    }

    internal ManagementStrategy(ITextTemplatingEngineHost host) { }

    internal virtual void CreateFile(String fileName, String content) {
        File.WriteAllText(fileName, content);
    }

    internal virtual void DeleteFile(String fileName) {
        if (File.Exists(fileName))
            File.Delete(fileName);
    }
}

class VSManagementStrategy : ManagementStrategy
{
    private EnvDTE.ProjectItem templateProjectItem;

    internal VSManagementStrategy(ITextTemplatingEngineHost host) : base(host) {
        IServiceProvider hostServiceProvider = (IServiceProvider)host;
        if (hostServiceProvider == null)
            throw new ArgumentNullException("Could not obtain hostServiceProvider");

        EnvDTE.DTE dte = (EnvDTE.DTE)hostServiceProvider.GetService(typeof(EnvDTE.DTE));
        if (dte == null)
            throw new ArgumentNullException("Could not obtain DTE from host");

        templateProjectItem = dte.Solution.FindProjectItem(host.TemplateFile);
    }
    //创建文件
    internal override void CreateFile(String fileName, String content) {
        base.CreateFile(fileName, content);
        ((EventHandler)delegate { templateProjectItem.ProjectItems.AddFromFile(fileName); }).BeginInvoke(null, null, null, null);
    }
    //删除文件
    internal override void DeleteFile(String fileName) {
        ((EventHandler)delegate { FindAndDeleteFile(fileName); }).BeginInvoke(null, null, null, null);
    }
    //根据文件名删除文件
    private void FindAndDeleteFile(String fileName) {
        foreach(EnvDTE.ProjectItem projectItem in templateProjectItem.ProjectItems) {
            if (projectItem.get_FileNames(0) == fileName) {
                projectItem.Delete();
                return;
            }
        }
    }
}#>

4 MySqlHelper.ttinclude文本文件

<#+
public class EntityHelper
    {
        public static List<Entity> GetEntities(string connectionString, List<string> databases)
        {
            var list = new List<Entity>();
            var conn = new MySqlConnection(connectionString);
            try
            {
                conn.Open();
                var dbs = string.Join("','", databases.ToArray());
                var cmd = string.Format(@"SELECT `information_schema`.`COLUMNS`.`TABLE_SCHEMA`
                                                    ,`information_schema`.`COLUMNS`.`TABLE_NAME`
                                                    ,`information_schema`.`COLUMNS`.`COLUMN_NAME`
                                                    ,`information_schema`.`COLUMNS`.`DATA_TYPE`
                                                    ,`information_schema`.`COLUMNS`.`COLUMN_COMMENT`
                                                FROM `information_schema`.`COLUMNS`
                                                WHERE `information_schema`.`COLUMNS`.`TABLE_SCHEMA` IN ('{0}') ", dbs);
                using (var reader = MySqlHelper.ExecuteReader(conn, cmd))
                {
                    while (reader.Read())
                    {
                        var db = reader["TABLE_SCHEMA"].ToString();
                        var table = reader["TABLE_NAME"].ToString();
                        var column = reader["COLUMN_NAME"].ToString();
                        var type =  reader["DATA_TYPE"].ToString();
                        var comment = reader["COLUMN_COMMENT"].ToString();
                        var entity = list.FirstOrDefault(x => x.EntityName == table);
                        if(entity == null)
                        {
                            entity = new Entity(table);
                            entity.Fields.Add(new Field
                            {
                                Name = column,
                                Type = GetCLRType(type),
                                Comment = comment
                            });
                           
                            list.Add(entity);
                        }
                        else
                        {
                            entity.Fields.Add(new Field
                            {
                                Name = column,
                                Type = GetCLRType(type),
                                Comment = comment
                            });
                        }
                    }
                }
            }
            finally
            {
                conn.Close();
            }

            return list;
        }

        public static string GetCLRType(string dbType)
        {
            switch(dbType)
            {
                case "tinyint":
                case "smallint":
                case "mediumint":
                case "int":
                case "integer":
                    return "int";
                case "double":
                    return "double";
                case "float":
                    return "float";
                case "decimal":
                    return "decimal";
                case "numeric":
                case "real":
                    return "decimal";
                case "bit":
                    return "bool";
                case "date":
                case "time":
                case "year":
                case "datetime":
                case "timestamp":
                    return "DateTime";
                case "tinyblob":
                case "blob":
                case "mediumblob":
                case "longblog":
                case "binary":
                case "varbinary":
                    return "byte[]";
                case "char":
                case "varchar":                   
                case "tinytext":
                case "text":
                case "mediumtext":
                case "longtext":
                    return "string";
                case "point":
                case "linestring":
                case "polygon":
                case "geometry":
                case "multipoint":
                case "multilinestring":
                case "multipolygon":
                case "geometrycollection":
                case "enum":
                case "set":
                default:
                    return dbType;
            }
        }
    }

    public class Entity
    {
        public Entity()
        {
            this.Fields = new List<Field>();
        }

        public Entity(string name)
            : this()
        {
            this.EntityName = name;
        }

        public string EntityName { get;set; }
        public List<Field> Fields { get;set; }
        public string PascalEntityName
        {
            get{
                return    CommonConver.ToPascalCase(this.EntityName);
            }
        }
        public string CamelEntityName
        {
            get{
                return    CommonConver.ToCamelCase(this.EntityName);
            }
        }
    }

    public class Field
    {
        public string Name { get;set; }
        public string Type { get;set; }
        public string Comment { get;set; }
    }
    public class CommonConver
    {
        public static string ToPascalCase(string tableName)
        {
            string upperTableName = tableName.Substring(0, 1).ToUpper() + tableName.Substring(1, tableName.Length - 1);
            return upperTableName;
        }    
        public static string ToCamelCase(string tableName)
        {
            string lowerTableName = tableName.Substring(0, 1).ToLower() + tableName.Substring(1, tableName.Length - 1);
            return lowerTableName;
        }    
    }

class config
    {
        
        public static readonly string ConnectionString = "Database=openauth;Data Source=127.0.0.1;User Id=root;Password=;pooling=false;CharSet=utf8;port=3306";
        public static readonly string DbDatabase = "";
        public static readonly string TableName = "";
        public static readonly string ModelNameSpace = "App.Entities";
        public static readonly string IRepositoryNameSpace = "App.IRepository";
        public static readonly string RepositoryNameSpace = "App.Repository";
        public static readonly string IServicesNameSpace = "App.IServices";
        public static readonly string ServicesNameSpace = "App.Services";
    }#>

5 模板文件Entity.tt

<#@ template debug="false" hostspecific="True" language="C#" #>
<#@ output extension=".cs" #>

<#@ assembly name="System.Core.dll" #>
<#@ assembly name="System.Data.dll" #>
<#@ assembly name="System.Data.DataSetExtensions.dll" #>
<#@ assembly name="System.Xml.dll" #>
<#@ assembly name="C:Userschuanchuan.nugetpackagesmysql.data8.0.14lib
et452MySql.Data.dll" #>
<#@ import namespace="System" #>
<#@ import namespace="System.Xml" #>
<#@ import namespace="System.Linq" #>
<#@ import namespace="System.Data" #>
<#@ import namespace="System.Data.SqlClient" #>
<#@ import namespace="System.Collections.Generic" #>
<#@ import namespace="System.IO" #>
<#@ import namespace="MySql.Data.MySqlClient" #>

<#@ include file="$(ProjectDir)MySqlHelper.ttinclude"  #>
<#@ include file="$(ProjectDir)ModelAuto.ttinclude"    #>

<#
    // 是否是WCF服务模型
    //C:Usersyouga.nugetpackagesmysql.data8.0.14lib
et452
    bool serviceModel = false;
   
    // 数据库连接
    var connectionString = @"Data Source=127.0.0.1;User Id=root;Password=;pooling=false;CharSet=utf8;port=3306";

    // 需要解析的数据库
    var database = new List<string> { "openauthdb" };

    // 文件版权信息
    var copyright = DateTime.Now.Year + " xxxx Enterprises All Rights Reserved";
    var version = Environment.Version;
    var author = "auto generated by T4";

     var OutputPath1 = Path.GetDirectoryName(Host.TemplateFile)+"\work";
    if (!Directory.Exists(OutputPath1))
    {
        Directory.CreateDirectory(OutputPath1);
    }

    var manager = new Manager(Host, GenerationEnvironment, true) { OutputPath = OutputPath1 };
    var entities = EntityHelper.GetEntities(connectionString, database);

    foreach(Entity entity in entities)
    {
        manager.StartBlock(entity.EntityName + ".cs");
#>
//-----------------------------------------------------------------------
// <copyright file=" <#= entity.EntityName #>.cs" company="xxxx Enterprises">
// * Copyright (C) <#= copyright #>
// * version : <#= version #>
// * author  : <#= author #>
// * FileName: <#= entity.EntityName #>.cs
// * history : Created by T4 <#= DateTime.Now #>
// </copyright>
//-----------------------------------------------------------------------
using System;
<#    if(serviceModel)
    {
#>
using System.Runtime.Serialization;
<#
    }
#>

namespace <#=config.ModelNameSpace#>
{
    /// <summary>
    /// <#= entity.EntityName #> Entity Model
    /// </summary>   
    [Serializable]
<#    if(serviceModel)
    {
#>
    [DataContract]
<#
    }
#>
    public class <#= entity.EntityName #>
    {
<#
        for(int i = 0; i < entity.Fields.Count; i++)
        {
            if(i ==0){
#>        /// <summary>
        /// <#= entity.Fields[i].Comment #>
        /// </summary>
<#    if(serviceModel)
    {
#>
        [DataMember]
<#
    }
#>
        public <#= entity.Fields[i].Type #> <#= entity.Fields[i].Name #> { get; set; }
<#
            }
            else{
#>   
        /// <summary>
        /// <#= entity.Fields[i].Comment #>
        /// </summary>
<#    if(serviceModel)
    {
#>
        [DataMember]
<#
    }
#>
        public <#= entity.Fields[i].Type #> <#= entity.Fields[i].Name #> { get; set; }
<#            }
        }
#>
    }
}
<#       
        manager.EndBlock();
    }

    manager.Process(true);
#>

 注意事项：

1、<#@ assembly name="C:Usersyouga.nugetpackagesmysql.data8.0.14lib et452MySql.Data.dll" #>  修改为你的引用；
2、MySqlHelper.ttinclude 修改ConnectionString变量；
3、App.Entities.tt 修改connectionString变量；
4、可以根据自己的需求修改T4模板；
5、生成的类名都是小写，可否转化为帕斯卡命名规范（待解决）； 

6、如果MySQL要生成大写的话，需要在my.ini中添加 lower_case_table_names=2，让mysql区分大小写，生成出来的就跟所设置的表名，字段名一样了，默认mysql在windows下不区分大小写。

<#@ template debug="false" hostspecific="True" language="C#" #><#@ output extension=".cs" #>
<#@ assembly name="System.Core.dll" #><#@ assembly name="System.Data.dll" #><#@ assembly name="System.Data.DataSetExtensions.dll" #><#@ assembly name="System.Xml.dll" #><#@ assembly name="C:Userschuanchuan.nugetpackagesmysql.data8.0.14lib et452MySql.Data.dll" #><#@ import namespace="System" #><#@ import namespace="System.Xml" #><#@ import namespace="System.Linq" #><#@ import namespace="System.Data" #><#@ import namespace="System.Data.SqlClient" #><#@ import namespace="System.Collections.Generic" #><#@ import namespace="System.IO" #><#@ import namespace="MySql.Data.MySqlClient" #>
<#@ include file="$(ProjectDir)MySqlHelper.ttinclude"  #><#@ include file="$(ProjectDir)ModelAuto.ttinclude"#>
<#    // 是否是WCF服务模型//C:Usersyouga.nugetpackagesmysql.data8.0.14lib et452    bool serviceModel = false;       // 数据库连接    var connectionString = @"Data Source=127.0.0.1;User Id=root;Password=;pooling=false;CharSet=utf8;port=3306";
    // 需要解析的数据库    var database = new List<string> { "openauthdb" };
    // 文件版权信息    var copyright = DateTime.Now.Year + " xxxx Enterprises All Rights Reserved";    var version = Environment.Version;    var author = "auto generated by T4";
var OutputPath1 = Path.GetDirectoryName(Host.TemplateFile)+"\work";if (!Directory.Exists(OutputPath1)){Directory.CreateDirectory(OutputPath1);}
    var manager = new Manager(Host, GenerationEnvironment, true) { OutputPath = OutputPath1 };    var entities = EntityHelper.GetEntities(connectionString, database);
    foreach(Entity entity in entities)    {        manager.StartBlock(entity.EntityName + ".cs");#>//-----------------------------------------------------------------------// <copyright file=" <#= entity.EntityName #>.cs" company="xxxx Enterprises">// * Copyright (C) <#= copyright #>// * version : <#= version #>// * author  : <#= author #>// * FileName: <#= entity.EntityName #>.cs// * history : Created by T4 <#= DateTime.Now #>// </copyright>//-----------------------------------------------------------------------using System;<#    if(serviceModel)    {#>using System.Runtime.Serialization;<#    }#>
namespace <#=config.ModelNameSpace#>{    /// <summary>    /// <#= entity.EntityName #> Entity Model    /// </summary>       [Serializable]<#    if(serviceModel)    {#>    [DataContract]<#    }#>    public class <#= entity.EntityName #>    {<#        for(int i = 0; i < entity.Fields.Count; i++)        {            if(i ==0){#>        /// <summary>        /// <#= entity.Fields[i].Comment #>        /// </summary><#    if(serviceModel)    {#>        [DataMember]<#    }#>        public <#= entity.Fields[i].Type #> <#= entity.Fields[i].Name #> { get; set; }<#            }            else{#>           /// <summary>        /// <#= entity.Fields[i].Comment #>        /// </summary><#    if(serviceModel)    {#>        [DataMember]<#    }#>        public <#= entity.Fields[i].Type #> <#= entity.Fields[i].Name #> { get; set; }<#            }        }#>    }}<#               manager.EndBlock();    }
    manager.Process(true);#>