T4模板——一个神奇的代码生成器

　　利用T4模板，可以很方便的从数据库映射成Model模型，相当于动软等功效。但动软是可以直接生成三层，抽象工厂的，T4没那么牛叉，所以我们一般只用作生成Modle或者Server等指定方法了。

废话少说，切入正题：

下面我将讲解的有两部分，一部分是根据T4将方法属性等生成到一个类里面，另一个是分配生成到不同类里面。

一.根据T4将方法生成到一个类里面

代码如下:

Customers.tt

<#@ assembly name="System.Core.dll" #>
<#@ assembly name="System.Data.dll" #>
<#@ assembly name="System.Data.DataSetExtensions.dll" #>
<#@ assembly name="System.Xml.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" #>

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

using System;
namespace T4ConsoleApplication.Entities
{    

    public class <#=config.TableName#>
    {
        <# foreach(DbColumn column in DbHelper.GetDbColumns(config.ConnectionString, config.DbDatabase, config.TableName)){#>

        public <#= column.CSharpType#><# if(column.CommonType.IsValueType && column.IsNullable){#>?<#}#> <#=column.ColumnName#> { get; set; }
        <#}#> 

    }
}

<#+
    public class config
    {
        //修改要生成的数据库表
        public static readonly string ConnectionString="Data Source=.;Integrated Security=true;";
        public static readonly string DbDatabase="Inferno";
        public static readonly string TableName="RepositoryModel";
    }
#>

DbHelper.ttinclude

<#+
    public class DbHelper
    {
        #region GetDbTables

        public static List<DbTable> GetDbTables(string connectionString, string database, string tables = null)
        {

            if (!string.IsNullOrEmpty(tables))
            {
                tables = string.Format(" and obj.name in ('{0}')", tables.Replace(",", "','"));
            }
            #region SQL
            string sql = string.Format(@"SELECT
                                    obj.name tablename,
                                    schem.name schemname,
                                    idx.rows,
                                    CAST
                                    (
                                        CASE
                                            WHEN (SELECT COUNT(1) FROM sys.indexes WHERE object_id= obj.OBJECT_ID AND is_primary_key=1) >=1 THEN 1
                                            ELSE 0
                                        END
                                    AS BIT) HasPrimaryKey
                                    from {0}.sys.objects obj
                                    inner join {0}.dbo.sysindexes idx on obj.object_id=idx.id and idx.indid<=1
                                    INNER JOIN {0}.sys.schemas schem ON obj.schema_id=schem.schema_id
                                    where type='U' {1}
                                    order by obj.name", database, tables);
            #endregion
            DataTable dt = GetDataTable(connectionString, sql);
            return dt.Rows.Cast<DataRow>().Select(row => new DbTable
            {
                TableName = row.Field<string>("tablename"),
                SchemaName = row.Field<string>("schemname"),
                Rows = row.Field<int>("rows"),
                HasPrimaryKey = row.Field<bool>("HasPrimaryKey")
            }).ToList();
        }
        #endregion

        #region GetDbColumns

        public static List<DbColumn> GetDbColumns(string connectionString, string database, string tableName, string schema = "dbo")
        {
            #region SQL
            string sql = string.Format(@"
                                    WITH indexCTE AS
                                    (
                                        SELECT
                                        ic.column_id,
                                        ic.index_column_id,
                                        ic.object_id
                                        FROM {0}.sys.indexes idx
                                        INNER JOIN {0}.sys.index_columns ic ON idx.index_id = ic.index_id AND idx.object_id = ic.object_id
                                        WHERE  idx.object_id =OBJECT_ID(@tableName) AND idx.is_primary_key=1
                                    )
                                    select
                                    colm.column_id ColumnID,
                                    CAST(CASE WHEN indexCTE.column_id IS NULL THEN 0 ELSE 1 END AS BIT) IsPrimaryKey,
                                    colm.name ColumnName,
                                    systype.name ColumnType,
                                    colm.is_identity IsIdentity,
                                    colm.is_nullable IsNullable,
                                    cast(colm.max_length as int) ByteLength,
                                    (
                                        case
                                            when systype.name='nvarchar' and colm.max_length>0 then colm.max_length/2
                                            when systype.name='nchar' and colm.max_length>0 then colm.max_length/2
                                            when systype.name='ntext' and colm.max_length>0 then colm.max_length/2
                                            else colm.max_length
                                        end
                                    ) CharLength,
                                    cast(colm.precision as int) Precision,
                                    cast(colm.scale as int) Scale,
                                    prop.value Remark
                                    from {0}.sys.columns colm
                                    inner join {0}.sys.types systype on colm.system_type_id=systype.system_type_id and colm.user_type_id=systype.user_type_id
                                    left join {0}.sys.extended_properties prop on colm.object_id=prop.major_id and colm.column_id=prop.minor_id
                                    LEFT JOIN indexCTE ON colm.column_id=indexCTE.column_id AND colm.object_id=indexCTE.object_id
                                    where colm.object_id=OBJECT_ID(@tableName)
                                    order by colm.column_id", database);
            #endregion
            SqlParameter param = new SqlParameter("@tableName", SqlDbType.NVarChar, ) { Value = string.Format("{0}.{1}.{2}", database, schema, tableName) };
              DataTable dt = GetDataTable(connectionString, sql, param);            

            return dt.Rows.Cast<DataRow>().Select(row => new DbColumn()
            {
                ColumnID = row.Field<int>("ColumnID"),
                IsPrimaryKey = row.Field<bool>("IsPrimaryKey"),
                ColumnName = row.Field<string>("ColumnName"),
                ColumnType = row.Field<string>("ColumnType"),
                IsIdentity = row.Field<bool>("IsIdentity"),
                IsNullable = row.Field<bool>("IsNullable"),
                ByteLength = row.Field<int>("ByteLength"),
                CharLength = row.Field<int>("CharLength"),
                Scale = row.Field<int>("Scale"),
                Remark = row["Remark"].ToString()
            }).ToList();
        }

        #endregion     

        #region GetDataTable

        public static DataTable GetDataTable(string connectionString, string commandText, params SqlParameter[] parms)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                SqlCommand command = connection.CreateCommand();
                command.CommandText = commandText;
                command.Parameters.AddRange(parms);
                SqlDataAdapter adapter = new SqlDataAdapter(command);
                DataTable dt = new DataTable();
                adapter.Fill(dt);

                return dt;
            }
        }

        #endregion
    }

    #region DbTable
    /// <summary>
    /// 表结构
    /// </summary>
    public sealed class DbTable
    {
        /// <summary>
        /// 表名称
        /// </summary>
        public string TableName { get; set; }
        /// <summary>
        /// 表的架构
        /// </summary>
        public string SchemaName { get; set; }
        /// <summary>
        /// 表的记录数
        /// </summary>
        public int Rows { get; set; }

        /// <summary>
        /// 是否含有主键
        /// </summary>
        public bool HasPrimaryKey { get; set; }
    }
    #endregion

    #region DbColumn
    /// <summary>
    /// 表字段结构
    /// </summary>
    public sealed class DbColumn
    {
        /// <summary>
        /// 字段ID
        /// </summary>
        public int ColumnID { get; set; }

        /// <summary>
        /// 是否主键
        /// </summary>
        public bool IsPrimaryKey { get; set; }

        /// <summary>
        /// 字段名称
        /// </summary>
        public string ColumnName { get; set; }

        /// <summary>
        /// 字段类型
        /// </summary>
        public string ColumnType { get; set; }

        /// <summary>
        /// 数据库类型对应的C#类型
        /// </summary>
        public string CSharpType
        {
            get
            {
                return SqlServerDbTypeMap.MapCsharpType(ColumnType);
            }
        }

        /// <summary>
        ///
        /// </summary>
        public Type CommonType
        {
            get
            {
                return SqlServerDbTypeMap.MapCommonType(ColumnType);
            }
        }

        /// <summary>
        /// 字节长度
        /// </summary>
        public int ByteLength { get; set; }

        /// <summary>
        /// 字符长度
        /// </summary>
        public int CharLength { get; set; }

        /// <summary>
        /// 小数位
        /// </summary>
        public int Scale { get; set; }

        /// <summary>
        /// 是否自增列
        /// </summary>
        public bool IsIdentity { get; set; }

        /// <summary>
        /// 是否允许空
        /// </summary>
        public bool IsNullable { get; set; }

        /// <summary>
        /// 描述
        /// </summary>
        public string Remark { get; set; }
    }
    #endregion

    #region SqlServerDbTypeMap

    public class SqlServerDbTypeMap
    {
        public static string MapCsharpType(string dbtype)
        {
            if (string.IsNullOrEmpty(dbtype)) return dbtype;
            dbtype = dbtype.ToLower();
            string csharpType = "object";
            switch (dbtype)
            {
                case "bigint": csharpType = "long"; break;
                case "binary": csharpType = "byte[]"; break;
                case "bit": csharpType = "bool"; break;
                case "char": csharpType = "string"; break;
                case "date": csharpType = "DateTime"; break;
                case "datetime": csharpType = "DateTime"; break;
                case "datetime2": csharpType = "DateTime"; break;
                case "datetimeoffset": csharpType = "DateTimeOffset"; break;
                case "decimal": csharpType = "decimal"; break;
                case "float": csharpType = "double"; break;
                case "image": csharpType = "byte[]"; break;
                case "int": csharpType = "int"; break;
                case "money": csharpType = "decimal"; break;
                case "nchar": csharpType = "string"; break;
                case "ntext": csharpType = "string"; break;
                case "numeric": csharpType = "decimal"; break;
                case "nvarchar": csharpType = "string"; break;
                case "real": csharpType = "Single"; break;
                case "smalldatetime": csharpType = "DateTime"; break;
                case "smallint": csharpType = "short"; break;
                case "smallmoney": csharpType = "decimal"; break;
                case "sql_variant": csharpType = "object"; break;
                case "sysname": csharpType = "object"; break;
                case "text": csharpType = "string"; break;
                case "time": csharpType = "TimeSpan"; break;
                case "timestamp": csharpType = "byte[]"; break;
                case "tinyint": csharpType = "byte"; break;
                case "uniqueidentifier": csharpType = "Guid"; break;
                case "varbinary": csharpType = "byte[]"; break;
                case "varchar": csharpType = "string"; break;
                case "xml": csharpType = "string"; break;
                default: csharpType = "object"; break;
            }
            return csharpType;
        }

        public static Type MapCommonType(string dbtype)
        {
            if (string.IsNullOrEmpty(dbtype)) return Type.Missing.GetType();
            dbtype = dbtype.ToLower();
            Type commonType = typeof(object);
            switch (dbtype)
            {
                case "bigint": commonType = typeof(long); break;
                case "binary": commonType = typeof(byte[]); break;
                case "bit": commonType = typeof(bool); break;
                case "char": commonType = typeof(string); break;
                case "date": commonType = typeof(DateTime); break;
                case "datetime": commonType = typeof(DateTime); break;
                case "datetime2": commonType = typeof(DateTime); break;
                case "datetimeoffset": commonType = typeof(DateTimeOffset); break;
                case "decimal": commonType = typeof(decimal); break;
                case "float": commonType = typeof(double); break;
                case "image": commonType = typeof(byte[]); break;
                case "int": commonType = typeof(int); break;
                case "money": commonType = typeof(decimal); break;
                case "nchar": commonType = typeof(string); break;
                case "ntext": commonType = typeof(string); break;
                case "numeric": commonType = typeof(decimal); break;
                case "nvarchar": commonType = typeof(string); break;
                case "real": commonType = typeof(Single); break;
                case "smalldatetime": commonType = typeof(DateTime); break;
                case "smallint": commonType = typeof(short); break;
                case "smallmoney": commonType = typeof(decimal); break;
                case "sql_variant": commonType = typeof(object); break;
                case "sysname": commonType = typeof(object); break;
                case "text": commonType = typeof(string); break;
                case "time": commonType = typeof(TimeSpan); break;
                case "timestamp": commonType = typeof(byte[]); break;
                case "tinyint": commonType = typeof(byte); break;
                case "uniqueidentifier": commonType = typeof(Guid); break;
                case "varbinary": commonType = typeof(byte[]); break;
                case "varchar": commonType = typeof(string); break;
                case "xml": commonType = typeof(string); break;
                default: commonType = typeof(object); break;
            }
            return commonType;
        }
    }
    #endregion

#>

效果展示:

二.根据T4将方法生成到多个类里面

生成实体总结:

Entity.tt

<#@ template debug="false" hostspecific="true" language="C#" #>
<#@ assembly name="System.Data" #>
<#@ assembly name="System.xml" #>
<#@ import namespace="System.Collections.Generic" #>
<#@ import namespace="System.Data.SqlClient" #>
<#@ import namespace="System.Data" #>
<#@ assembly name="System.Core" #>
<#@ import namespace="System.Linq" #>

//  导入MultipleOutputHelper.ttinclude文件
<#@ include file="..\MultipleOutputHelper.ttinclude" #>

<#
        string connectionString= "server=.;database=Inferno;Integrated Security=true;";
        SqlConnection conn = new SqlConnection(connectionString);
        conn.Open();

        string selectQuery ="SET FMTONLY ON; select * from @tableName; SET FMTONLY OFF;";
        SqlCommand command = new SqlCommand(selectQuery,conn);
        SqlDataAdapter ad = new SqlDataAdapter(command);
        System.Data.DataSet ds = new DataSet(); 

        var manager = Manager.Create(Host, GenerationEnvironment);  

        System.Data.DataTable schema = conn.GetSchema("Tables");
        foreach(System.Data.DataRow row in schema.Rows)
        {
            ds.Tables.Clear();
            string tb_name= row["TABLE_NAME"].ToString();
            command.CommandText = selectQuery.Replace("@tableName",row["TABLE_NAME"].ToString());
            ad.FillSchema(ds, SchemaType.Mapped,tb_name);  

            manager.StartNewFile(tb_name+".cs");#>

using FluentData;
using System;
using System.Collections.Generic;
namespace MY.Model
{
    /// <summary>
    /// 实体-<#=tb_name#>
    /// </summary>
    public partial class <#=tb_name#>
    {
        <#
        PushIndent("          ");
        foreach (DataColumn dc in ds.Tables[].Columns)
        {
            WriteLine("public " + dc.DataType.Name+ (dc.AllowDBNull && dc.DataType.Name.ToLower() != "string" ? "? ": " ") + dc.ColumnName + " { get; set; }");
        }
        PopIndent();
        #>
    }
}

<#
        manager.EndBlock();
         }
        conn.Close();
       manager.Process(true);
        #> 

业务逻辑总结:

Action.tt

<#@ template debug="false" hostspecific="true" language="C#" #>
<#@ assembly name="System.Data" #>
<#@ assembly name="System.xml" #>
<#@ import namespace="System.Collections.Generic" #>
<#@ import namespace="System.Data.SqlClient" #>
<#@ import namespace="System.Data" #>
<#@ assembly name="System.Core" #>
<#@ import namespace="System.Linq" #>

//  导入MultipleOutputHelper.ttinclude文件
<#@ include file="..\MultipleOutputHelper.ttinclude" #>
<#
        string connectionString= "server=.;database=Inferno;Integrated Security=true;";
        SqlConnection conn = new SqlConnection(connectionString);
        conn.Open();

        string selectQuery ="SET FMTONLY ON; select * from @tableName; SET FMTONLY OFF;";
        SqlCommand command = new SqlCommand(selectQuery,conn);
        SqlDataAdapter ad = new SqlDataAdapter(command);
        System.Data.DataSet ds = new DataSet(); 

        var manager = Manager.Create(Host, GenerationEnvironment);  

        System.Data.DataTable schema = conn.GetSchema("Tables");
        foreach(System.Data.DataRow row in schema.Rows)
        {
            ds.Tables.Clear();
            string tb_name= row["TABLE_NAME"].ToString();
            command.CommandText = selectQuery.Replace("@tableName",row["TABLE_NAME"].ToString());
            ad.FillSchema(ds, SchemaType.Mapped,tb_name);
            manager.StartNewFile(tb_name+"Action.cs");#>

using System;
using System.Collections.Generic;
using MY.Model;
namespace MY.BLL
{    

    /// <summary>
    /// <#=tb_name#> 操作类
    /// </summary>
    public partial class <#=tb_name#>Action
    {<#
        string fkQuery = " SELECT f.name AS ForeignKey,";
        fkQuery += " OBJECT_NAME(f.parent_object_id) AS TableName, ";
        fkQuery += " COL_NAME(fc.parent_object_id, fc.parent_column_id) AS ColumnName, ";
        fkQuery += " OBJECT_NAME (f.referenced_object_id) AS ReferenceTableName, ";
        fkQuery += " COL_NAME(fc.referenced_object_id, fc.referenced_column_id) AS ReferenceColumnName ";
        fkQuery += " FROM ";
        fkQuery += " sys.foreign_keys AS f ";
        fkQuery += " INNER JOIN sys.foreign_key_columns AS fc ON f.OBJECT_ID = fc.constraint_object_id ";
        fkQuery += " where OBJECT_NAME(f.parent_object_id) = '" +tb_name +"'";

        List<string> fkColumnNames = new List<string>();
        Dictionary<string, string> parentTables = new Dictionary<string, string>();

        SqlCommand command2 = new SqlCommand(fkQuery,conn);
        using(var dr = command2.ExecuteReader())
        {
            while(dr.Read())
            {
                fkColumnNames.Add(dr["ColumnName"].ToString());
                parentTables.Add(dr["ColumnName"].ToString(), dr["ReferenceTableName"].ToString());
            }
            dr.Close();
        }

        List<DataColumn> fkColumns = new List<DataColumn>();
        foreach(string fkColumnName in fkColumnNames)
        {
            foreach (DataColumn dc in ds.Tables[].Columns)
            {
                if(dc.ColumnName == fkColumnName)
                    fkColumns.Add(dc);
            }
        }

        List<string> primaryKeyParamsWithTypes = new List<string>();
        List<string> primaryKeyParams = new List<string>();
        List<string> whereItems = new List<string>();
        List<string> automapItems = new List<string>();
        foreach(DataColumn pk in ds.Tables[].PrimaryKey)
        {
            primaryKeyParamsWithTypes.Add(string.Format("{0} {1}", pk.DataType.Name, this.ToCamelCase(pk.ColumnName)));
            primaryKeyParams.Add(pk.ColumnName);
            whereItems.Add(string.Format("{0} = @{1}", pk.ColumnName, pk.ColumnName.ToLower()));
            automapItems.Add(string.Format("x.{0}", pk.ColumnName));
        }

        string updateAutomap = string.Empty;
    if(automapItems.Count > ){
        if(automapItems.Count > )
            updateAutomap = "new { " + string.Join(", ", automapItems.ToArray()) + " }";
        else
            updateAutomap = automapItems[];
            }
        #>

        public static <#=tb_name#> Select(<#=string.Join(", ", primaryKeyParamsWithTypes.ToArray())#>)
        {
            using(var context = db.Context())
            {
                return context.Sql(" SELECT * FROM <#=tb_name#> WHERE <#=string.Join(" AND ", whereItems.ToArray())#> ")
                    <#foreach(string pkp in primaryKeyParams)
                    {
                        WriteLine(".Parameter(\"" + pkp.ToLower() + "\", " + this.ToCamelCase(pkp) + ")");
                    }
                    #>
                    .QuerySingle<<#=tb_name#>>();
            }
        }

        public static List<<#=tb_name#>> SelectAll()
        {
            return SelectAll(string.Empty);
        }

        public static List<<#=tb_name#>> SelectAll(string sortExpression)
        {
            return SelectAll(, , sortExpression);
        }

        public static List<<#=tb_name#>> SelectAll(int startRowIndex, int maximumRows, string sortExpression)
        {
            using (var context = db.Context())
            {
                var select = context.Select<<#=tb_name#>>(" * ")
                    .From(" <#=tb_name#> ");

                if (maximumRows > )
                {
                    if (startRowIndex == )
                        startRowIndex = ;

                    select.Paging(startRowIndex, maximumRows);
                }

                if (!string.IsNullOrEmpty(sortExpression))
                    select.OrderBy(sortExpression);

                return select.QueryMany();
            }
        }

        public static int CountAll()
        {
            using (var context = db.Context())
            {
                return context.Sql(" SELECT COUNT(*) FROM <#=tb_name#> ")
                    .QuerySingle<int>();
            }
        }

        <#
        foreach(DataColumn dc in fkColumns)
        {
        #>

        public static List<<#=tb_name#>> SelectBy<#=parentTables[dc.ColumnName]#>(<#=dc.DataType.Name#> <#=this.ToCamelCase(dc.ColumnName)#>)
        {
            return SelectBy<#=parentTables[dc.ColumnName]#>(<#=this.ToCamelCase(dc.ColumnName)#>, string.Empty);
        }

        public static List<<#=tb_name#>> SelectBy<#=parentTables[dc.ColumnName]#>(<#=dc.DataType.Name#> <#=this.ToCamelCase(dc.ColumnName)#>, string sortExpression)
        {
            return SelectBy<#=parentTables[dc.ColumnName]#>(<#=this.ToCamelCase(dc.ColumnName)#>, , , sortExpression);
        }

        public static List<<#=tb_name#>> SelectBy<#=parentTables[dc.ColumnName]#>(<#=dc.DataType.Name#> <#=this.ToCamelCase(dc.ColumnName)#>, int startRowIndex, int maximumRows, string sortExpression)
        {
            using (var context = db.Context())
            {
                var select = context.Select<<#=tb_name#>>(" * ")
                    .From(" <#=tb_name#> ")
                    .Where(" <#=dc.ColumnName#> = @<#=dc.ColumnName.ToLower()#> ")
                    .Parameter("<#=dc.ColumnName.ToLower()#>", <#=this.ToCamelCase(dc.ColumnName)#>);

                if (maximumRows > )
                {
                    if (startRowIndex == )
                        startRowIndex = ;

                    select.Paging(startRowIndex, maximumRows);
                }

                if (!string.IsNullOrEmpty(sortExpression))
                    select.OrderBy(sortExpression);

                return select.QueryMany();
            }
        }

        public static int CountBy<#=parentTables[dc.ColumnName]#>(<#=dc.DataType.Name#> <#=this.ToCamelCase(dc.ColumnName)#>)
        {
            using (var context = db.Context())
            {
                return context.Sql(" SELECT COUNT(*) FROM <#=tb_name#> WHERE <#=dc.ColumnName#> = @<#=dc.ColumnName.ToLower()#>")
                    .Parameter("<#=dc.ColumnName.ToLower()#>", <#=this.ToCamelCase(dc.ColumnName)#>)
                    .QuerySingle<int>();
            }
        }
        <#}#>

<#if(ds.Tables[0].PrimaryKey != null && ds.Tables[0].PrimaryKey.Length == 1 && ds.Tables[0].PrimaryKey[0].AutoIncrement) {#>
        public static bool Insert(<#=tb_name#> <#=this.ToCamelCase(tb_name)#>)
        {
            using (var context = db.Context())
            {
                int id = context.Insert<<#=tb_name#>>("<#=tb_name#>", <#=this.ToCamelCase(tb_name)#>)
                    .AutoMap(x => x.<#=primaryKeyParams[]#>)
                    .ExecuteReturnLastId<int>();

                <#=this.ToCamelCase(tb_name)#>.<#=primaryKeyParams[]#> = id;
                return id > ;
            }
        }
<#
}
else
{
#>
        public static bool Insert(<#=tb_name#> <#=this.ToCamelCase(tb_name)#>)
        {
            using (var context =db.Context())
            {
                return context.Insert<<#=tb_name#>>("<#=tb_name#>", <#=this.ToCamelCase(tb_name)#>)
                    .Execute() > ;
            }
        }
<#}#>
        public static bool Update(<#=tb_name#> <#=this.ToCamelCase(tb_name)#>)
        {
            using (var context = db.Context())
            {
                return context.Update<<#=tb_name#>>("<#=tb_name#>", <#=this.ToCamelCase(tb_name)#>)
                    .AutoMap(x => <#=updateAutomap#>)
                    <#foreach(string pkp in primaryKeyParams){#>
                    .Where("<#=pkp#>", <#=this.ToCamelCase(tb_name)#>.<#=pkp#>)
                    <#}#>
                    .Execute() > ;
            }
        }

        public static bool Delete(<#=tb_name#> <#=this.ToCamelCase(tb_name)#>)
        {
            return Delete(<#=string.Join(", ", primaryKeyParams.Select(x=> this.ToCamelCase(tb_name) + "." + x).ToArray())#>);
        }

        public static bool Delete(<#=string.Join(", ", primaryKeyParamsWithTypes.ToArray())#>)
        {
            using (var context = db.Context())
            {
                return context.Sql(" DELETE FROM Product WHERE <#=string.Join(" AND ", whereItems.ToArray())#> ")
                    <#foreach(string pkp in primaryKeyParams) {
                        WriteLine(".Parameter(\"" + pkp.ToLower() + "\", " + this.ToCamelCase(pkp) + ")");
                    }#>
                    .Execute() > ;
            }
        }
    }

}

<#
        manager.EndBlock();
         }
        conn.Close();
       manager.Process(true);
        #> 

<#+
    public string ToCamelCase(string value)
    {
        if(string.IsNullOrEmpty(value))
            return string.Empty;

        string firstLetter = value.Substring(, );
        string rest = value.Substring(, value.Length - );
        return firstLetter.ToLower() + rest;
    }
#>

-----------------------

MultipleOutputHelper.ttinclude代码

<#@ assembly name="System.Core"
#><#@ assembly name="System.Data.Linq"
#><#@ assembly name="EnvDTE"
#><#@ assembly name="System.Xml"
#><#@ assembly name="System.Xml.Linq"
#><#@ import namespace="System"
#><#@ import namespace="System.CodeDom"
#><#@ import namespace="System.CodeDom.Compiler"
#><#@ import namespace="System.Collections.Generic"
#><#@ import namespace="System.Data.Linq"
#><#@ import namespace="System.Data.Linq.Mapping"
#><#@ import namespace="System.IO"
#><#@ import namespace="System.Linq"
#><#@ import namespace="System.Reflection"
#><#@ import namespace="System.Text"
#><#@ import namespace="System.Xml.Linq"
#><#@ import namespace="Microsoft.VisualStudio.TextTemplating"
#><#+

// Manager class records the various blocks so it can split them up
class Manager {
    private class Block {
        public String Name;
        public int Start, Length;
        public bool IncludeInDefault;
    }

    private Block currentBlock;
    private List<Block> files = new List<Block>();
    private Block footer = new Block();
    private Block header = new Block();
    private ITextTemplatingEngineHost host;
    private StringBuilder template;
    protected List<String> generatedFileNames = new List<String>();

    public static Manager Create(ITextTemplatingEngineHost host, StringBuilder template) {
        return (host is IServiceProvider) ? new VSManager(host, template) : new Manager(host, template);
    }

    public void StartNewFile(String name) {
        if (name == null)
            throw new ArgumentNullException("name");
        CurrentBlock = new Block { Name = name };
    }

    public void StartFooter(bool includeInDefault = true) {
        CurrentBlock = footer;
        footer.IncludeInDefault = includeInDefault;
    }

    public void StartHeader(bool includeInDefault = true) {
        CurrentBlock = header;
        header.IncludeInDefault = includeInDefault;
    }

    public void EndBlock() {
        if (CurrentBlock == null)
            return;
        CurrentBlock.Length = template.Length - CurrentBlock.Start;
        if (CurrentBlock != header && CurrentBlock != footer)
            files.Add(CurrentBlock);
        currentBlock = null;
    }

    public virtual void Process(bool split, bool sync = true) {
        if (split) {
            EndBlock();
            String headerText = template.ToString(header.Start, header.Length);
            String footerText = template.ToString(footer.Start, footer.Length);
            String outputPath = Path.GetDirectoryName(host.TemplateFile);
            files.Reverse();
            if (!footer.IncludeInDefault)
                template.Remove(footer.Start, footer.Length);
            foreach(Block block in files) {
                String fileName = Path.Combine(outputPath, block.Name);
                String content = headerText + template.ToString(block.Start, block.Length) + footerText;
                generatedFileNames.Add(fileName);
                CreateFile(fileName, content);
                template.Remove(block.Start, block.Length);
            }
            if (!header.IncludeInDefault)
                template.Remove(header.Start, header.Length);
        }
    }

    protected virtual void CreateFile(String fileName, String content) {
        if (IsFileContentDifferent(fileName, content))
            File.WriteAllText(fileName, content);
    }

    public virtual String GetCustomToolNamespace(String fileName) {
        return null;
    }

    public virtual String DefaultProjectNamespace {
        get { return null; }
    }

    protected bool IsFileContentDifferent(String fileName, String newContent) {
        return !(File.Exists(fileName) && File.ReadAllText(fileName) == newContent);
    }

    private Manager(ITextTemplatingEngineHost host, StringBuilder template) {
        this.host = host;
        this.template = template;
    }

    private Block CurrentBlock {
        get { return currentBlock; }
        set {
            if (CurrentBlock != null)
                EndBlock();
            if (value != null)
                value.Start = template.Length;
            currentBlock = value;
        }
    }

    private class VSManager: Manager {
        private EnvDTE.ProjectItem templateProjectItem;
        private EnvDTE.DTE dte;
        private Action<String> checkOutAction;
        private Action<IEnumerable<String>> projectSyncAction;

        public override String DefaultProjectNamespace {
            get {
                return templateProjectItem.ContainingProject.Properties.Item("DefaultNamespace").Value.ToString();
            }
        }

        public override String GetCustomToolNamespace(string fileName) {
            return dte.Solution.FindProjectItem(fileName).Properties.Item("CustomToolNamespace").Value.ToString();
        }

        public override void Process(bool split, bool sync) {
            if (templateProjectItem.ProjectItems == null)
                return;
            base.Process(split, sync);
            if (sync)
                projectSyncAction.EndInvoke(projectSyncAction.BeginInvoke(generatedFileNames, null, null));
        }

        protected override void CreateFile(String fileName, String content) {
            if (IsFileContentDifferent(fileName, content)) {
                CheckoutFileIfRequired(fileName);
                File.WriteAllText(fileName, content);
            }
        }

        internal VSManager(ITextTemplatingEngineHost host, StringBuilder template)
            : base(host, template) {
            var hostServiceProvider = (IServiceProvider) host;
            if (hostServiceProvider == null)
                throw new ArgumentNullException("Could not obtain IServiceProvider");
            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);
            checkOutAction = (String fileName) => dte.SourceControl.CheckOutItem(fileName);
            projectSyncAction = (IEnumerable<String> keepFileNames) => ProjectSync(templateProjectItem, keepFileNames);
        }

        private static void ProjectSync(EnvDTE.ProjectItem templateProjectItem, IEnumerable<String> keepFileNames) {
            var keepFileNameSet = new HashSet<String>(keepFileNames);
            var projectFiles = new Dictionary<String, EnvDTE.ProjectItem>();
            var originalFilePrefix = Path.GetFileNameWithoutExtension(templateProjectItem.get_FileNames()) + ".";
            foreach(EnvDTE.ProjectItem projectItem in templateProjectItem.ProjectItems)
                projectFiles.Add(projectItem.get_FileNames(), projectItem);

            // Remove unused items from the project
            foreach(var pair in projectFiles)
                if (!keepFileNames.Contains(pair.Key) && !(Path.GetFileNameWithoutExtension(pair.Key) + ".").StartsWith(originalFilePrefix))
                    pair.Value.Delete();

            // Add missing files to the project
            foreach(String fileName in keepFileNameSet)
                if (!projectFiles.ContainsKey(fileName))
                    templateProjectItem.ProjectItems.AddFromFile(fileName);
        }

        private void CheckoutFileIfRequired(String fileName) {
            var sc = dte.SourceControl;
            if (sc != null && sc.IsItemUnderSCC(fileName) && !sc.IsItemCheckedOut(fileName))
                checkOutAction.EndInvoke(checkOutAction.BeginInvoke(fileName, null, null));
        }
    }
} #>

ZJ