c# 使用T4模板生成实体类（sqlserver）

新建类库，右键添加 "文本模板"

添加完成之后生成如下后缀为 tt的文件：

双击文件：TextTemplate_Test.tt 文件打开，替换代码如下

 <#@ template debug="false" hostspecific="true" language="C#" #>
 <#@ assembly name="System.Core" #>
 <#@ assembly name="System.Data" #>
 <#@ assembly name="System.xml" #>
 <#@ import namespace="System.Linq" #>
 <#@ import namespace="System.Text" #>
 <#@ import namespace="System.Collections.Generic" #>
 <#@ import namespace="System.Data.SqlClient" #>
 <#@ import namespace="System.Data" #>
 <#@ include file="ModelAuto.ttinclude"#>
 <#@ output extension=".cs" #>

 <# var manager = new Manager(Host, GenerationEnvironment, true) { OutputPath = Path.GetDirectoryName(Host.TemplateFile)}; #>
 <#
     //数据库连接
     string connectionString ="Data Source=127.0.0.1;Initial Catalog=TestDB;User ID=sa;Password=123456;";
     SqlConnection conn = new SqlConnection(connectionString);
     conn.Open();
     //查询表
     System.Data.DataTable schema = conn.GetSchema("TABLES");
     string selectQuery = "select * from @tableName";   //查询表语句
     SqlCommand command = new SqlCommand(selectQuery,conn);
     SqlDataAdapter ad = new SqlDataAdapter(command);
     System.Data.DataSet ds = new DataSet();
     //查询字段
     string propQuery = "SELECT 表名=sobj.name,字段名=scol.name,字段说明=sprop.[value] FROM syscolumns as scol inner join sys.sysobjects as sobj on scol.id=sobj.id and sobj.xtype='U' and sobj.name<>'dtproperties' left join sys.extended_properties as sprop on scol.id=sprop.major_id and scol.colid=sprop.minor_id where sobj.name='@tableName' and scol.name='@columnName'";
     SqlCommand command2 = new SqlCommand(propQuery,conn);
     SqlDataAdapter ad2 = new SqlDataAdapter(command2);
     System.Data.DataSet ds2 = new DataSet();
  #>

 <# foreach(System.Data.DataRow row in schema.Rows) { #>
 <# manager.StartBlock(row["TABLE_NAME"].ToString()+".cs"); #>
 using System;

 namespace Entity.Model
 {
     /// <summary>
     /// 实体类：<#= row["TABLE_NAME"].ToString() #>
     /// </summary>
     [Serializable]
     public class <#= row["TABLE_NAME"].ToString() #>
     {
         <#
         ds.Tables.Clear();
         command.CommandText = selectQuery.Replace("@tableName","["+row["TABLE_NAME"].ToString()+"]");
         ad.FillSchema(ds, SchemaType.Mapped, row["TABLE_NAME"].ToString());
         foreach (DataColumn dc in ds.Tables[].Columns)
         {
         #>
             <#
             ds2.Tables.Clear();
             command2.CommandText = propQuery.Replace("@tableName",row["TABLE_NAME"].ToString());
             command2.CommandText = command2.CommandText.Replace("@columnName",dc.ColumnName);
             ad2.Fill(ds2);
             #>

         ///<summary>
         ///<#= manager.TransFromSqlType(dc.DataType.Name) #>:<#=ds2.Tables[0].Rows[0].ItemArray[2]#>
         ///</summary>
         public <#= manager.TransFromSqlType(dc.DataType.Name) #> <#= dc.ColumnName #> { get; set; }
         <#}#>
     }
 }

 <# manager.EndBlock(); #>

 <#}#>

 <#manager.Process(true);#>

需要更换几个配置的地方：

1，设置数据库连接，找到该段代码：string connectionString ="Data Source=127.0.0.1;Initial Catalog=TestDB;User ID=sa;Password=123456;";  替换你要连接的数据库即可；

2，设置命名空间，找到代码：namespace Entity.Model {....} ，将该处的命名空间替换你要的即可；

3，相同目录下添加代码自动生成逻辑文件，文件名字为：ModelAuto.ttinclude

文件内容如下，

 <#@ 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"#>

 <#+

 class Manager
 {
     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; }

     public Manager(ITextTemplatingEngineHost host, StringBuilder template, bool commonHeader) {
         this.host = host;
         this.template = template;
         OutputPath = String.Empty;
         strategy = ManagementStrategy.Create(host);
     }

     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);
     }

     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) {
             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);
             }
         }
     }

         /// <summary>
         /// SQL[不完善,需要的自己改造]
         /// 更换字段类型
         /// </summary>
         /// <param name="type"></param>
         /// <returns></returns>
         public string TransFromSqlType(string type)
         {
             if (string.IsNullOrEmpty(type))
             {
                 return string.Empty;
             }
             if (string.Equals(type, "Boolean", StringComparison.OrdinalIgnoreCase))
             {
                 return "bool";
             }
             else if (string.Equals(type, "Int32", StringComparison.OrdinalIgnoreCase))
             {
                 return "int";
             }
             else if (string.Equals(type, "Int64", StringComparison.OrdinalIgnoreCase))
             {
                 return "long";
             }
             else if (string.Equals(type, "String", StringComparison.OrdinalIgnoreCase))
             {
                 return "string";
             }
             else if(string.Equals(type, "Byte", StringComparison.OrdinalIgnoreCase))
             {
                 return "byte";
             }
             else if (string.Equals(type, "Decimal", StringComparison.OrdinalIgnoreCase))
             {
                 return "decimal";
             }
             else if (string.Equals(type, "datetime", StringComparison.OrdinalIgnoreCase))
             {
                 return "DateTime";
             }
             return "string";
         }

 }

 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);
     }

     internal override void CreateFile(String fileName, String content) {
         base.CreateFile(fileName, content);
         ((EventHandler)delegate { templateProjectItem.ProjectItems.AddFromFile(fileName); }).BeginInvoke(null, null, null, null);
     }

     internal override void DeleteFile(String fileName) {
         ((EventHandler)delegate { FindAndDeleteFile(fileName); }).BeginInvoke(null, null, null, null);
     }

     private void FindAndDeleteFile(String fileName) {
         foreach(EnvDTE.ProjectItem projectItem in templateProjectItem.ProjectItems) {
             if (projectItem.get_FileNames() == fileName) {
                 projectItem.Delete();
                 return;
             }
         }
     }
 }#>

接下来就是见证奇迹的时刻，选中 TextTemplate_Test.tt 文件 按 Ctrl+C即可(每次更新实体类时,需要先修改一下模板文件,随便修改什么地方，按个空格也可以)，生成模板代码如下：