C#利用IDbDataAdapter/IDataReader实现通用数据集获取

using System.Data;
using System.Data.SqlClient;
using System.Data.OracleClient;
using Dm;
using System.Collections;

public System.Data.IDbDataAdapter GetDataAdapter(string dbservertype)
{
    IDbDataAdapter adp = null;
    switch (dbservertype.ToLower())
    {
        case "oracle": adp =new OracleDataAdapter(); break;
        case "dm8": adp = new  DmDataAdapter(); break;
        default: adp =new SqlDataAdapter(); break;
    }
    return adp;
}

public object GetDataSet(string DbServerType,string strConn,string _sql,ArrayList paras,CommandType ct)
{
            System.Data.IDbConnection Conn=GetConnection(DbServerType,strConn);
            System.Data.IDbCommand Cmd=GetCommand(DbServerType,_sql,paras,Conn);
            Cmd.CommandType=ct;
            DataSet ds=new DataSet();
            try
            {
                ds.EnforceConstraints=false;
                Conn.Open();
                System.Data.IDbDataAdapter adp=GetDataAdapter(DbServerType);
                adp.SelectCommand=Cmd;
                
                adp.FillSchema(ds,System.Data.SchemaType.Mapped);
                adp.Fill(ds);
                return ds;
            }
            catch (Exception e)
            {
                return e.Message;
            }
            finally
            {
                if(Conn.State==ConnectionState.Open)
                {
                    Conn.Close();
                }
            }
}

public System.Data.IDataReader GetDataReader2(string DbServerType,string strConn,string _sql, ArrayList paras, CommandType ct)
{
      System.Data.IDbConnection Conn = GetConnection(DbServerType, strConn);
      System.Data.IDbCommand Cmd = GetCommand(DbServerType, _sql, paras, Conn);
      Cmd.CommandType = ct;
      Cmd.Connection = Conn;
      Conn.Open();
      return Cmd.ExecuteReader();
 
}