一段由数据库结构生成相应数据对象的代码（1）(2) (3)--DataHelper

一段由数据库结构生成相应数据对象的代码（1）--DataHelper
using System;
namespace DataMap
{
 /// <summary>
 /// DataHelper 的摘要说明。
 /// </summary>
 public class DataHelper
 {
  static private IDataHelper _Instance;
  public static IDataHelper getInstance()
  {
   if(_Instance==null)
    _Instance=new SqlDataHelper();
   return _Instance;
  }
 }
}

一段由数据库结构生成相应数据对象的代码（2）--IDataHelper
using System;
namespace DataMap
{
 /// <summary>
 /// IDataHelper 的摘要说明。
 /// </summary>
 public interface IDataHelper
 {
  System.Collections.ArrayList FillDataObject(Type type);
  System.Collections.SortedList getMetaData();
  System.Type getTypeByDbType(string dbType);
 }
}

发表于 @ 2004年05月10日 10:21 PM | 评论 (0)

一段由数据库结构生成相应数据对象的代码（3）--SqlDataHelper
using System;
using System.Reflection;
using System.Data.SqlClient;
using System.Data;
namespace DataMap
{
 /// <summary>
 /// SqlDataHelper 的摘要说明。
 /// </summary>
 public class SqlDataHelper:IDataHelper
 {
  string _ConnectionString="user id=sa;password=;initial catalog=hrs;data source=(local);Connect Timeout=30";
  string _DatabaseName="northwind";
  public string ConnnectionString
  {
   get
   {
    return _ConnectionString;
   }
   set
   {
    _ConnectionString=value;
   }
  }
  public System.Collections.ArrayList FillDataObject(System.Type type,SqlDataReader dr)
  {
   System.Collections.ArrayList al=new System.Collections.ArrayList();
   if(type==null)
    return al;
   while(dr.Read())
   {
    object obj=System.Activator.CreateInstance(type);
    System.Reflection.PropertyInfo[] pi=type.GetProperties();
    for(int i=0;i<pi.Length;i++)
    {
     DataAtAttribute[] daProp=(DataAtAttribute[])pi[i].GetCustomAttributes(typeof(DataAtAttribute),true);
     if(daProp.Length>0)
     {
      if(dr[daProp[0].DataField]!=DBNull.Value)
       try
       {
        pi[i].SetValue(obj,dr[daProp[0].DataField],null);
       }
       catch(IndexOutOfRangeException e)
       {
       }
     }
    }
    al.Add(obj);
   }
   dr.Close();
   return al;
  }
  public System.Collections.ArrayList FillDataObject(System.Type type)
  {
   DataAtAttribute[] daClass=(DataAtAttribute[])type.GetCustomAttributes(typeof(DataAtAttribute),true);
   if(daClass.Length==0)
    return new System.Collections.ArrayList();
   string tableName=daClass[0].DataField;
   string sql="SELECT * FROM "+tableName;
   SqlDataReader dr=getDataReader(sql);
   return FillDataObject(type,dr);
  }
  private SqlDataReader getDataReader(string sql)
  {
   SqlConnection cn=new SqlConnection(_ConnectionString);
   SqlCommand cmd=new SqlCommand(sql,cn);
   cn.Open();
   SqlDataReader dr=cmd.ExecuteReader(CommandBehavior.CloseConnection);
   return dr;
  }
  public System.Collections.SortedList getMetaData()
  {
   System.Collections.SortedList slTable;
   slTable=new System.Collections.SortedList();
   SqlConnection cn=new SqlConnection(_ConnectionString);
   cn.Open();
   SqlCommand cmd=new SqlCommand("sp_help",cn);
   cmd.CommandType=CommandType.StoredProcedure;
   SqlDataReader dr=cmd.ExecuteReader();
   while(dr.Read())
   {
    if(dr["object_type"].ToString().Trim()=="user table")
    {
     slTable.Add(dr["name"].ToString(),null);
    }
   }
   dr.Close();
   for(int i=0;i<slTable.Keys.Count;i++)
   {
    System.Collections.SortedList slColumn;
    slColumn=new System.Collections.SortedList();
    string table=slTable.GetKey(i).ToString();
    cmd.CommandType=CommandType.Text;
    cmd.CommandText="SELECT o.name table_name,c.name column_name,t.name type FROM sysobjects o,syscolumns c,systypes t WHERE o.[id]=c.[id] AND c.xtype=t.xusertype AND o.name='"+table+"'";
    dr=cmd.ExecuteReader();
    while(dr.Read())
    {
     slColumn.Add(dr["column_name"].ToString(),dr["type"].ToString());
    }
    dr.Close();
    slTable=slColumn;
   }
   cn.Close();
   return slTable;
  }
  public System.Type getTypeByDbType(string dbType)
  {
   switch(dbType)
   {
    case "bigint":
     return typeof(System.Int64);
    case "int":
     return typeof(System.Int32);
    case "bit":
     return typeof(System.Boolean);
    case "char":
    case "nchar":
    case "ntext":
    case "varchar":
    case "nvarchar":
    case "text":
     return typeof(System.String);
    case "datetime":
    case "smalldatetime":
     return typeof(System.DateTime);
    case "decimal":
    case "numeric":
     return typeof(System.Decimal);
    case "float":
    case "real":
     return typeof(System.Single);
    case "smallint":
    case "tinyint":
     return typeof(System.Int16);
    case "image":
    case "money":
    case "smallmoney":
    case "sql_variant":
    case "sysname":
    case "timestamp":
    case "uniqueidentifier":
    case "varbinary":
     return typeof(System.Object);
    default:
     return typeof(System.Object);
   }
  }
 }
}

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