C#winform中从数据库中读取数据

使用以下引用：

using System.Data.OracleClient;

OracleDataReader readData;

//从数据库中读取数据
string cmdstr = "SELECT * FROM ROLLDATA_ONLINE order by ROLLPOS asc ";

 readData = ZAndromeda.OracleAcessTools.Utilities.getDataReader(cmdstr);

while (readData.Read())
        {
                    if (readData[0] != DBNull.Value)
                    {

                       var1 = readData.GetValue(0).ToString();
                        var2 = (float)Convert.ToDouble(readData.GetValue(1).ToString());
                    }
         }
 readData.Close();
readData.Dispose();