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[0].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(0) == 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：