为数据库中的表 生成类的源文件（代码生成器）

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.IO;
using System.Text;

namespace ModelCodeGeneratorSample
{
    class Program
    {
        static string ConnectionString;
        static string NamespaceName;

        static Program()
        {
            //载入配置
            ConnectionString = "Data Source=192.168.8.119;Initial Catalog=22TopWeb;Integrated Security=False;user=EQCCD_HUNTER;password=zhey1bu2012;";
            NamespaceName = "Topuc22Top.Model";
        }

        static void Main(string[] args)
        {
            var content = GetTableCodeContent(ConnectionString, NamespaceName, "TB_Enterprise");
            if (!string.IsNullOrWhiteSpace(content)) 
            {
                string descFileFolder = @"D:";
                if (!Directory.Exists(descFileFolder))
                    Directory.CreateDirectory(descFileFolder);
                string descFileName = "\TB_Enterprise.cs";
                File.WriteAllText(descFileFolder + descFileName, content, System.Text.Encoding.UTF8);
            }
        }

        static string GetTableCodeContent(string conStr, string namespaceName, string tableName, string className = "")
            //为什么不直接用全局的 少传一个参数，曾经一个项目 的 经验
        {
            if (string.IsNullOrWhiteSpace(tableName))
            {
                throw new ArgumentException("参数tableName不能为Empty、null或WhiteSpce");
            }
            var sb = new StringBuilder();
            sb.AppendFormat(@"
namespace {0}
{{
    public class {1}
    {{", namespaceName, (!string.IsNullOrWhiteSpace(className) ? className : tableName));
            var dt = GetTableFields(conStr, tableName);
            foreach (DataRow row in dt.Rows)
            {
                var columnName = row["列名"];
                var typeString = row["类型"];
                var isNullable = row["是否为空"];
                var description = row["列说明"];
                sb.AppendFormat(@"
        /// <summary>
        /// {3}
        /// </summary>
        public {1}{2}  {0} {{ get; set; }}", columnName, typeString, (typeString.ToString() != "string" && isNullable.ToString() == "是" ? "?" : ""), description);
            }

            sb.AppendFormat(@"
    }}
}}
", NamespaceName);

            return sb.ToString();
        }

        static DataTable GetTableFields(string conStr, string tableName = "")
        {
            var sql = GetSql(tableName);
            var dt = ExcuteQuery(conStr, sql);
            return dt;
        }

        static string GetSql(string tableName = "")
        {
            var sql = @"select  
    [表名]=c.Name, 
    [表说明]=isnull(f.[value],''),  
    [列序号]=a.Column_id,  
    [列名]=a.Name,  
    [列说明]=isnull(e.[value],''),  
    [数据库类型]=b.Name,    
    [类型]= case when b.Name = 'image' then 'byte[]'
                 when b.Name in('image','uniqueidentifier','ntext','varchar','ntext','nchar','nvarchar','text','char') then 'string'
                 when b.Name in('tinyint','smallint','int','bigint') then 'int'
                 when b.Name in('date','datetime','smalldatetime') then 'DateTime'
                 when b.Name in('float','decimal','numeric','money','real','smallmoney') then 'decimal'
                 when b.Name ='bit' then 'bool' else b.name end ,
    [标识]= case when is_identity=1 then '是' else '' end,  
    [主键]= case when exists(select 1 from sys.objects x join sys.indexes y on x.Type=N'PK' and x.Name=y.Name  
                        join sysindexkeys z on z.ID=a.Object_id and z.indid=y.index_id and z.Colid=a.Column_id)  
                    then '是' else '' end,      
    [字节数]=case when a.[max_length]=-1 and b.Name!='xml' then 'max/2G'  
                  when b.Name='xml' then '2^31-1字节/2G' 
                  else rtrim(a.[max_length]) end,  
    [长度]=case when ColumnProperty(a.object_id,a.Name,'Precision')=-1 then '2^31-1' 
                else rtrim(ColumnProperty(a.object_id,a.Name,'Precision')) end,  
    [小数位]=isnull(ColumnProperty(a.object_id,a.Name,'Scale'),0),  
    [是否为空]=case when a.is_nullable=1 then '是' else '' end,      
    [默认值]=isnull(d.text,'')      
from  
    sys.columns a  
left join 
    sys.types b on a.user_type_id=b.user_type_id  
inner join 
    sys.objects c on a.object_id=c.object_id and c.Type='U' 
left join 
    syscomments d on a.default_object_id=d.ID  
left join 
    sys.extended_properties e on e.major_id=c.object_id and e.minor_id=a.Column_id and e.class=1   
left join 
    sys.extended_properties f on f.major_id=c.object_id and f.minor_id=0 and f.class=1 
where 1 = 1";
            if (!string.IsNullOrWhiteSpace(tableName))
            {
                sql += "and c.name = '" + tableName + "'";
            }
            sql += " order by c.name, is_identity desc, a.Column_id";

            return sql;
        }

        static DataTable ExcuteQuery(string conStr, string cmdText, List<SqlParameter> pars = null)
        {
            using (SqlConnection conn = new SqlConnection(conStr))
            {
                using (SqlCommand cmd = new SqlCommand(cmdText, conn))
                {
                    if (pars != null && pars.Count > 0) cmd.Parameters.AddRange(pars.ToArray());
                    using (SqlDataAdapter adp = new SqlDataAdapter(cmd))
                    {
                        DataTable dt = new DataTable();
                        adp.Fill(dt);
                        return dt;
                    }
                }
            }
        }

    }
}

生成的.cs文件内容