C#编写T4模板实现数据表到实体类的映射

开发工具：VS2017、SQLServer2017、PL/SQL

准备工作：下载并安装T4Toolbox

1、创建文件EntityTemplate.tt、EntityProperties.tt，注意选择这个哦

EntityTemplate.tt内容如下：

<#+
public class EntityTemplate : CSharpTemplate
{
	private string tableName;
	private string colProperties;

	public EntityTemplate(string tableName,string colProperties)
    {
        this.tableName = tableName;
		this.colProperties = colProperties;
    }

	public override string TransformText()
	{
		base.TransformText();
#>
using System;

namespace Model.DefaultDB
{
    public class <#= tableName #>
    {
        <#= colProperties #>
    }
}
<#+
        return this.GenerationEnvironment.ToString();
	}
}
#>

 EntityProperties.tt内容如下：

<#+
public class EntityProperties : CSharpTemplate
{

	private string colName;
	private string colType;
	private string colDesc;

	public EntityProperties(string colName,string colType,string colDesc)
    {
        this.colName = colName;
		this.colType = colType;
		this.colDesc = colDesc;
    }

	public string DbTypeConvert(string dbType)
	{
		dbType = dbType.ToString().ToLower();
		switch (dbType)
		{
			case "char":
			case "varchar":
			case "varchar2":
			case "nvarchar":
			case "nvarchar2":
			case "clob":
			case "nclob":
			case "xmltype":
				{
					return "string";
				}
			case "date":
			case "datetime":
			case "datetime2":
				{
					return "DateTime";
				}
			case "tinyint":
				{
					return "byte";
				}
			case "number":
				{
					return "int";
				}
			case "uniqueidentifier":
				{
					return "Guid";
				}
			default:
				{
					return dbType;
				}
		}
	}

	public override string TransformText()
	{
		base.TransformText();
#>
        /// <summary>
        /// <#= colDesc #>
        /// </summary>
        public <#= DbTypeConvert(colType) #> <#= colName #> { get; set; }
<#+
        return this.GenerationEnvironment.ToString();
	}
}
#>

 2、创建SQLServerDefaultDB.tt、OracleDefaultDB.tt，模板为vs自带的

SQLServerDefaultDB.tt内容如下：

<#@ template debug="true" hostspecific="true" language="C#" #>
<#@ assembly name="$(SolutionDir)LibCore.dll" #>
<#@ assembly name="$(SolutionDir)LibDal.dll" #>
<#@ assembly name="System.Core" #>
<#@ assembly name="System.Data" #>
<#@ import namespace="Core" #>
<#@ import namespace="Dal" #>
<#@ import namespace="System.Collections.Generic" #>
<#@ import namespace="System.Data" #>
<#@ import namespace="System.IO" #>
<#@ import namespace="System.Linq" #>
<#@ import namespace="System.Text" #>
<#@ import namespace="System.Text.RegularExpressions" #>
<#@ include file="T4Toolbox.tt" #>
<#@ include file="EntityTemplate.tt" #>
<#@ include file="EntityProperties.tt" #>
<#
	//连接字符串
	string connStr = "Data Source=.;Initial Catalog=DefaultDB;enlist=false;User ID=sa;Password=123456";

	//查询所有用户表
	string sqlQueryTables = "select 表名=o.name from sys.sysobjects as o where o.xtype='U' and o.name<>'dtproperties' order by o.name";

	//查询表定义
	string sqlQueryColumns = @"
SELECT
表名=o.name,
字段名 = c.name,
类型 = t.name,
说明 = p.[value] 
FROM syscolumns as c
inner join sys.sysobjects as o on c.id = o.id and o.xtype = 'U' and o.name <> 'dtproperties'
inner join sys.systypes as t on c.xusertype = t.xusertype
left join sys.extended_properties as p on c.id = p.major_id and c.colid = p.minor_id
 order by o.name";

	//替换T4模板中多余的注释
	Regex reg1 = new Regex("// <autogenerated>
");
	Regex reg2 = new Regex("//   This file was generated by T4 code generator SQLServerDefaultDB.tt.
");
	Regex reg3 = new Regex("//   Any changes made to this file manually will be lost next time the file is regenerated.
");
	Regex reg4 = new Regex("// </autogenerated>
");

	//创建实体类存放路径
    string curPath = Path.GetDirectoryName(Host.TemplateFile);
    string defaultDBPath = Path.Combine(curPath, "DefaultDB");
    if(!Directory.Exists(defaultDBPath))
    {
        Directory.CreateDirectory(defaultDBPath);
    }

	var dbProvider = new SQLServerService(connStr);

	var dsTableName = dbProvider.ExecuteQuery(sqlQueryTables);
	var dsColumnInfo = dbProvider.ExecuteQuery(sqlQueryColumns);

	foreach (DataRow rTableName in dsTableName.Tables[0].Rows)
	{
		var tableName = rTableName["表名"].ToString();
		StringBuilder colProperties = new StringBuilder();
		foreach (DataRow rColumnInfo in dsColumnInfo.Tables[0].Rows)
		{
			if (rColumnInfo["表名"].ToString() == tableName)
			{
				EntityProperties prop = new EntityProperties(rColumnInfo["字段名"].ToString(),rColumnInfo["类型"].ToString(),rColumnInfo["说明"].ToString());
				var propStr = prop.TransformText();
				var propStrNew = reg1.Replace(propStr, "");
				propStrNew = reg2.Replace(propStrNew, "");
				propStrNew = reg3.Replace(propStrNew, "");
				propStrNew = reg4.Replace(propStrNew, "");
				colProperties.AppendLine(propStrNew);
			}
		}

		string fileName = string.Format(@"{0}{1}.cs", defaultDBPath, tableName);
		EntityTemplate template = new EntityTemplate(tableName,colProperties.ToString());
        template.Output.Encoding = Encoding.UTF8;
        template.RenderToFile(fileName);
	}
 #>

 OracleDefaultDB.tt内容如下：

<#@ template debug="true" hostspecific="true" language="C#" #>
<#@ assembly name="$(SolutionDir)LibCore.dll" #>
<#@ assembly name="$(SolutionDir)LibDal.dll" #>

<#@ assembly name="System.Core" #>
<#@ assembly name="System.Data" #>
<#@ import namespace="Core" #>
<#@ import namespace="Dal" #>

<#@ import namespace="System.Collections.Generic" #>
<#@ import namespace="System.Data" #>
<#@ import namespace="System.IO" #>
<#@ import namespace="System.Linq" #>
<#@ import namespace="System.Text" #>
<#@ import namespace="System.Text.RegularExpressions" #>
<#@ include file="T4Toolbox.tt" #>
<#@ include file="EntityTemplate.tt" #>
<#@ include file="EntityProperties.tt" #>
<#
	//连接字符串
	string connStr = "Data Source=(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=00.000.00.000)(PORT=0000))(CONNECT_DATA=(SID=GZTNS)));User ID=DefaultDB;Password=123456";

	//查询所有用户表
	string sqlQueryTables = "select distinct o.table_name 表名 from user_tab_columns o order by o.table_name";

	//查询表定义
	string sqlQueryColumns = @"
select 
o.table_name 表名,
c.column_name 字段名,
o.data_type 类型,
c.comments 说明 
from user_col_comments c 
inner join user_tab_columns o on c.column_name = o.column_name and c.table_name = o.table_name  order by o.table_name";

	//替换T4模板中多余的注释
	Regex reg1 = new Regex("// <autogenerated>
");
	Regex reg2 = new Regex("//   This file was generated by T4 code generator OracleDefaultDB.tt.
");
	Regex reg3 = new Regex("//   Any changes made to this file manually will be lost next time the file is regenerated.
");
	Regex reg4 = new Regex("// </autogenerated>
");

	//创建实体类存放路径
    string curPath = Path.GetDirectoryName(Host.TemplateFile);
    string defaultDBPath = Path.Combine(curPath, "DefaultDB_Oracle");
    if(!Directory.Exists(defaultDBPath))
    {
        Directory.CreateDirectory(defaultDBPath);
    }

	var dbProvider = new OracleService(connStr);

	var dsTableName = dbProvider.ExecuteQuery(sqlQueryTables);
	var dsColumnInfo = dbProvider.ExecuteQuery(sqlQueryColumns);

	foreach (DataRow rTableName in dsTableName.Tables[0].Rows)
	{
		var tableName = rTableName["表名"].ToString();
		StringBuilder colProperties = new StringBuilder();
		foreach (DataRow rColumnInfo in dsColumnInfo.Tables[0].Rows)
		{
			if (rColumnInfo["表名"].ToString() == tableName)
			{
				EntityProperties prop = new EntityProperties(rColumnInfo["字段名"].ToString(),rColumnInfo["类型"].ToString(),rColumnInfo["说明"].ToString());
				var propStr = prop.TransformText();
				var propStrNew = reg1.Replace(propStr, "");
				propStrNew = reg2.Replace(propStrNew, "");
				propStrNew = reg3.Replace(propStrNew, "");
				propStrNew = reg4.Replace(propStrNew, "");
				colProperties.AppendLine(propStrNew);
			}
		}

		string fileName = string.Format(@"{0}{1}.cs", defaultDBPath, tableName);
		EntityTemplate template = new EntityTemplate(tableName,colProperties.ToString());
        template.Output.Encoding = Encoding.UTF8;
        template.RenderToFile(fileName);
	}
 #>

 实体类存放路径自己定义，搞定后，选择SQLServerDefaultDB.tt或OracleDefaultDB.tt，右击->运行自定义工具

如果数据库是SQLServer的话，可以打开profiler看下

PS：数据库访问部分，是ADO.NET的。若oracle，需要引用Oracle.DataAccess.dll。

最后生成的结果图如下：

DefaultDB_Oracle，184个数据表，16/17秒瞬间搞定~~

搬砖，努力搬砖。