c# 利用t4模板，自动生成Model类

我们在用ORM（比如dapper）的时候，很多时候都需要自己写Model层（当然也有很多orm框架自带了这种功能，比如ef），特别是表里字段比较多的时候，一个Model要写半天，而且Model如果用于MVVM中，我们还需要添加PropertyChanged触发代码。发现t4模板可以自动生成代码，于是就写了一个。这个t4模板文件用了很久了，分享下。

<#@ template debug="false" hostspecific="false" 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" #>
<#@ 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="DbHelper.ttinclude"  #>
//------------------------------------------------------------------------------
//       生成时间 <#=DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss")#> by ly
//------------------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace NFMES.Model
{    

<#
    string tables="CK_T_Template,CK_T_MES_MV,CK_T_MES_RPT,CK_T_MES_ROUNTINGS";
    string[] ts=tables.Split(new char[]{','});
    for (int i=;i<ts.Length;i++)
    {
        string tableName=ts[i];

 #>

    public partial class <#= tableName #>:ModelBase

    {
        <# foreach(DbColumn column in DbHelper.GetDbColumns(config.ConnectionString, config.DbDatabase, tableName)){#>

        /// <summary>
        /// <#=column.Remark#>
        /// </summary>
        private <#= column.CSharpType#><# if(column.CommonType.IsValueType && column.IsNullable){#>?<#}#> _<#=column.ColumnName#> ;

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

        }
        }
        <#}#> 

    }
    <#
}
 #>
}

<#+
    public class config
    {
        public static readonly string ConnectionString="Data Source=192.168.1.135;Initial Catalog=dbname;User ID=sa;pwd=xxx";
        public static readonly string DbDatabase="dbname";

    }
#>

从代码里可以看出，我们在每个生成的属性里，都添加了 RaisePropertyChanged("<#=column.ColumnName#>")，这样生成的Model也可以自动触发PropertyChanged事件了。

这一行 string tables="CK_T_Template,CK_T_MES_MV,CK_T_MES_RPT,CK_T_MES_ROUNTINGS"对应于数据库中的表名，你想将哪个表转化成Model，就将表名写这，保存下就会自动生成一个与表名一样的类。

这个t4模板引用了一个ttinclude文件，这个文件主要处理，根据表名从数据库获取表结构，字段类型等。

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

<#+
    public class DbHelper
    {
        #region GetDbTables

        public static List<DbTable> GetDbTables(string connectionString, string database)
        {
      string tables="";
            #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);
            }
        }

        public string DbType
        {
        get
        {
        return SqlServerDbTypeMap.MapDBType(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 string MapDBType(string dbtype)
        {
            if (string.IsNullOrEmpty(dbtype)) return dbtype;
            dbtype = dbtype.ToLower();
            string csharpType = "object";
            switch (dbtype)
            {
                case "bigint": csharpType = "DbType.Int64"; break;
                case "binary": csharpType = "DbType.Binary"; break;
                case "bit": csharpType = "DbType.Boolean"; break;
                case "char": csharpType = "DbType.String"; break;
                case "date": csharpType = "DbType.DateTime"; break;
                case "datetime": csharpType = "DbType.DateTime"; break;
                case "datetime2": csharpType = "DbType.DateTime2"; break;
                case "datetimeoffset": csharpType = "DbType.DateTimeOffset"; break;
                case "decimal": csharpType = "DbType.Decimal"; break;
                case "float": csharpType = "DbType.Double"; break;
                case "image": csharpType = "DbType.Binary"; break;
                case "int": csharpType = "DbType.Int32"; break;
                case "money": csharpType = "DbType.Currency"; break;
                case "nchar": csharpType = "DbType.StringFixedLength"; break;
                case "ntext": csharpType = "DbType.String"; break;
                case "numeric": csharpType = "DbType.Decimal"; break;
                case "nvarchar": csharpType = "DbType.String"; break;
                case "real": csharpType = "DbType.Single"; break;
                case "smalldatetime": csharpType = "DbType.DateTime"; break;
                case "smallint": csharpType = "DbType.Int16"; break;
                case "smallmoney": csharpType = "DbType.Decimal"; break;
                case "sql_variant": csharpType = "DbType.Object"; break;
                case "sysname": csharpType = "DbType.Object"; break;
                case "text": csharpType = "DbType.String"; break;
                case "time": csharpType = "DbType.DateTime"; break;
                case "timestamp": csharpType = "DbType.Binary"; break;
                case "tinyint": csharpType = "DbType.Byte"; break;
                case "uniqueidentifier": csharpType = "DbType.Guid"; break;
                case "varbinary": csharpType = "DbType.Binary"; break;
                case "varchar": csharpType = "DbType.AnsiString"; break;
                case "xml": csharpType = "DbType.Xml"; break;
                default: csharpType = "DbType.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

#>

t4文件保存后，会自动生成类文件

这样，我们省去了很多代码量。