VS连接/操作Oracle数据库所需代码

using CropOffline;
using Oracle.ManagedDataAccess.Client;

public OracleConnection oraConnection;

private bool oraConnect()
        {
            try
            {
                //连接字符串
                string strOraConnect = "User ID=建立连接用的账号;Password=建立连接用的密码;Data Source=(DESCRIPTION = (ADDRESS_LIST= (ADDRESS = (PROTOCOL = TCP)(HOST =localhost)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME =数据库名称)))";
                oraConnection = new OracleConnection(strOraConnect);
                //给全局变量赋值
                DbHelperOra.connectionString = strOraConnect;
                oraConnection.Open();
                return true;//string.Empty;
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
                return false;
            }
        }

private void Form1_Load(object sender,EventArgs e)
{
    oraConnect();
       dataGridView1.DataSource=DbHelperOra.QueryToDataTable("select 哼哼哈嘿 from dual");
}    

需要DbHelperOra这个类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
//For Connect Oracle
using Oracle.ManagedDataAccess.Client;
//For ArrayList C#
using System.Collections;
//For DataSet C#
using System.Data;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;
using System.Runtime.Serialization;
namespace CropOffline
{
    [Serializable] //表示该类可被序列化
    class DbHelperOra
    {
        //
        //数据库连接字符串(web.config来配置)，可以动态更改connectionString支持多数据库.        
        public static string connectionString = "null";//PubConstant.ConnectionString;
        public DbHelperOra()
        {
        }

        #region 公用方法

        //J 为啥要+1呢，我就想不通了。表格中的数据类型需要是number
        public static int GetMaxID(string FieldName, string TableName)
        {
            string strsql = "select max(" + FieldName + ") from " + TableName;
            object obj = GetSingle(strsql);
            if (obj == null)
            {
                return 1;
            }
            else
            {
                return int.Parse(obj.ToString());
            }
        }

        //J 调试用，用来检查连接字符串是否有误
        public static string GetMaxIDT(string FieldName, string TableName)
        {
            string strsql = "select max(" + FieldName + ") from " + TableName;
            object obj = GetSingle(strsql);
            if (obj == null)
            {
                return 1.ToString();
            }
            else
            {
                return obj.ToString();
                //return strsql;
            }
        }
        /// <summary>
        /// 向数据库里插入图像格式的字段(和上面情况类似的另一种实例)
        /// </summary>
        /// <param name="strSQL">SQL语句</param>
        /// <param name="fs">图像字节,数据库的字段类型为image的情况</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSqlInsertImg(string strSQL, byte[] fs)
        {
            using (OracleConnection connection = new OracleConnection(connectionString))
            {
                OracleCommand cmd = new OracleCommand(strSQL, connection);
                OracleParameter myParameter = new OracleParameter("@fs", OracleDbType.LongRaw);
                myParameter.Value = fs;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                }
                catch (OracleException E)
                {
                    throw new Exception(E.Message);
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }
        /// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）。
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <returns>查询结果（object）</returns>
        public static object GetSingle(string SQLString)
        {
            using (OracleConnection connection = new OracleConnection(connectionString))
            {
                using (OracleCommand cmd = new OracleCommand(SQLString, connection)
                    )
                {
                    try
                    {
                        connection.Open();
                        object obj = cmd.ExecuteScalar();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return null;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (OracleException e)
                    {
                        connection.Close();
                        throw new Exception(e.Message);
                    }
                }
            }
        }
        
        /// 将一个object对象序列化，返回一个byte[]         
        /// </summary> 
        /// <param name="obj">能序列化的对象</param>         
        /// <returns></returns> 
        
        public static byte[] ObjectToBytes(object obj)
        {
            if(obj!=null)
            {
                using (MemoryStream ms = new MemoryStream())
                {
                    IFormatter formatter = new BinaryFormatter();
                    formatter.Serialize(ms, obj);
                    return ms.ToArray();
                }
            }
            return null;
        }

        #region 测试序列化byte类型
        public static byte[] SerializeObject(object obj)
        {
            IFormatter formatter = new BinaryFormatter();
            //string result = string.Empty;
            using (MemoryStream stream = new MemoryStream())
            {
                formatter.Serialize(stream, obj);

                byte[] byt = new byte[stream.Length];
                byt = stream.ToArray();
                // result = Encoding.UTF8.GetString(byt, 0, byt.Length);
                //result = Convert.ToBase64String(byt);
                stream.Flush();
                return byt;
            }

        }

        #endregion
        /// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）。
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <returns>查询结果（object）</returns>
        public static object GetSingle(string SQLString, params OracleParameter[] cmdParms)
        {
            using (OracleConnection connection = new OracleConnection(connectionString))
            {
                using (OracleCommand cmd = new OracleCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                        object obj = cmd.ExecuteScalar();
                        cmd.Parameters.Clear();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return null;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (OracleException e)
                    {
                        throw new Exception(e.Message);
                    }
                }
            }
        }

        private static void PrepareCommand(OracleCommand cmd, OracleConnection conn, OracleTransaction trans, string cmdText, OracleParameter[] cmdParms)
        {
            if (conn.State != ConnectionState.Open)
                conn.Open();
            cmd.Connection = conn;
            cmd.CommandText = cmdText;
            if (trans != null)
                cmd.Transaction = trans;
            cmd.CommandType = CommandType.Text;//cmdType;
            if (cmdParms != null)
            {
                foreach (OracleParameter parm in cmdParms)
                    cmd.Parameters.Add(parm);
            }
        }
        /// <summary>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">多条SQL语句</param>        
        public static void ExecuteSqlTran(ArrayList SQLStringList)
        {
            using (OracleConnection conn = new OracleConnection(connectionString))
            {
                conn.Open();
                OracleCommand cmd = new OracleCommand();
                cmd.Connection = conn;
                OracleTransaction tx = conn.BeginTransaction();
                cmd.Transaction = tx;
                try
                {
                    for (int n = 0; n < SQLStringList.Count; n++)
                    {
                        string strsql = SQLStringList[n].ToString();
                        if (strsql.Trim().Length > 1)
                        {
                            cmd.CommandText = strsql;
                            cmd.ExecuteNonQuery();
                        }
                    }
                    tx.Commit();
                }
                catch (OracleException E)
                {
                    tx.Rollback();
                    throw new Exception(E.Message);
                }
            }
        }
        /// <summary>
        /// 执行SQL语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString)
        {
            using (OracleConnection connection = new OracleConnection(connectionString))
            {
                using (OracleCommand cmd = new OracleCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        int rows = cmd.ExecuteNonQuery();
                        return rows;
                    }
                    catch (OracleException E)
                    {
                        connection.Close();
                        throw new Exception(E.Message);
                    }
                }
            }
        }

        /// <summary>
        /// 执行SQL语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString, params OracleParameter[] cmdParms)
        {
            using (OracleConnection connection = new OracleConnection(connectionString))
            {
                using (OracleCommand cmd = new OracleCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                        int rows = cmd.ExecuteNonQuery();
                        cmd.Parameters.Clear();
                        return rows;
                    }
                    catch (OracleException E)
                    {
                        throw new Exception(E.Message);
                    }
                }
            }
        }

        public static bool Exists(string strSql)
        {
            object obj = GetSingle(strSql);
            int cmdresult;
            if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
            {
                cmdresult = 0;
            }
            else
            {
                cmdresult = int.Parse(obj.ToString());
            }
            if (cmdresult == 0)
            {
                return false;
            }
            else
            {
                return true;
            }
        }

        /// <summary>
        /// 执行查询语句，返回DataSet
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataSet</returns>
        public static DataSet Query(string SQLString)
        {
            using (OracleConnection connection = new OracleConnection(connectionString))
            {
                DataSet ds = new DataSet();
                try
                {
                    connection.Open();
                    OracleDataAdapter command = new OracleDataAdapter(SQLString, connection);
                    command.Fill(ds, "ds");
                }
                catch (OracleException ex)
                {
                    throw new Exception(ex.Message);
                }
                return ds;
            }
        }
        /// <summary>
        /// 执行查询语句，返回DataTable
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataSet</returns>
        public static DataTable QueryToDataTable(string SQLString)
        {
            using (OracleConnection connection = new OracleConnection(connectionString))
            {
                DataTable dt = new DataTable();
                try
                {
                    connection.Open();
                    OracleDataAdapter command = new OracleDataAdapter(SQLString, connection);
                    command.Fill(dt);
                }
                catch (OracleException ex)
                {
                    throw new Exception(ex.Message);
                }
                return dt;
            }
        }
        #endregion
    }
}