如何在C＃中创建一个oracleconnection方法，以便可以重用它来获取下一个数据库 [英] How to create a class of method for oracleconnection in a C# so that it can be reused for next database to be fetched

问题描述

我是一个非常新的c＃编程初学者，因为我现在在c＃中模糊不清，所以我会被要求在下面的代码中为OracleConnection数据库创建一个方法，这样它就可以了重复使用，没有再次打字。我附上了我的代码。感谢您的帮助。

Hi i am a pretty new beginner in c# programming i wi sh to seek help as i am blur in c# now... So i was asked to create a method for the OracleConnection database at the code below so that it could be reused without having ti type it once again. Hereby i attached my code. Thanks for the help.

using System;
using System.Collections.Generic;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Oracle.DataAccess;
using Oracle.DataAccess.Client; //ODP.NET ORacle managed provider

namespace WindowsFormsApp7
{
    public partial class MyApp : Form
    {

        public MyApp()
        {
            InitializeComponent();
        }

        private void dataGridView1_CellContentClick(object sender, DataGridViewCellEventArgs e)
        {

        }

        private void Form1_Load(object sender, EventArgs e)
        {
            string OracleServer = "Data Source=mydb;"
            + "User Id=Config;Password=config123;"; //  your username and password database server

            OracleConnection conn = new OracleConnection(OracleServer);
            conn.Open();
            string orcl = @"Select * FROM mydatabase";
            OracleCommand cmd = new OracleCommand(orcl);

            cmd.Connection = conn;
            OracleDataAdapter da = new OracleDataAdapter();
            DataTable dt = new DataTable();
            da.SelectCommand = cmd;
            da.Fill(dt);

            listBoxdB.DataSource = dt;
            listBoxdB.ValueMember = "Database_id";
            listBoxdB.DisplayMember = "Location";

            this.dataGridView1.DataSource = dt;
            this.dataGridView1.Refresh();


            conn.Close();
            conn.Dispose();
        }

        private void listBoxdB_SelectedIndexChanged(object sender, EventArgs e)
        {
            string strDbID = Convert.ToString(listBoxdB.SelectedValue);
            string strDbLocation = Convert.ToString(listBoxdB.GetItemText(listBoxdB.SelectedItem));

            string strSql = @"select Name, id from my_source
                            where id not in (select id
                            from new_database
                            where database_id = " + strDbID + ")";

            string OracleServer = "Data Source=mydb;"
                                   + "User Id=config;Password=config123;"; 

            OracleConnection conn = new OracleConnection(OracleServer);
            conn.Open();
            OracleCommand cmd = new OracleCommand(strSql);
            cmd.Connection = conn;
            OracleDataAdapter da = new OracleDataAdapter();
            DataTable dt = new DataTable();
            da.SelectCommand = cmd;


            try
            {
                da.Fill(dt);

                this.listBoxApp.DataSource = dt;
                this.listBoxApp.ValueMember = "Application_id";
                this.listBoxApp.DisplayMember = "Application_Name";

            }
            catch { }

        }


        private void listBoxApp_SelectedIndexChanged(object sender, EventArgs e)
        {

        }
    }
}

我有什么试过：



我一直在尝试创建一个类，但c＃似乎不像我之前学过的其他编程，如c和c ++。 ..

What I have tried:

I've been tried creating a class but c# doesn't seems like the other programming i have learnt before such as c and c++...

推荐答案

如果我正确理解你的问题，我不会尝试存储连接以供以后重用。相反，我会让连接池来处理缓存连接对象。请查看 Oracle Data Provider for .NET的功能 [< a href =https://docs.oracle.com/cd/B19306_01/win.102/b14307/featConnecting.htm#i1006393\"target =_ blanktitle =New Window> ^ ]



连接字符串本身的内容，您可以存储它以便快速访问，例如在配置文件中，在单个静态字符串变量等中。



例如，看看在C＃中读取配置设置的四种方法 [ ^ ]

If I understand your question correctly, I wouldn't try to store the connection for later reuse. Instead I would let connection pooling to take care of caching the connection objects. Have a look at Features of Oracle Data Provider for .NET[^]

What comes to the connection string itself, you can store it for quick access for example in a configuration file, in a single, static string variable etc.

For example, have a look at Four Ways to Read Configuration Setting in C#[^]

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