C#存取SQL Server數據庫之二:利用序列化進行類鏈表存取(ArrayList,varbinary)

創建項目

1.      添加一個名爲RWTest的表到 SQL Server MYTest 數據庫。 表字段設置如下:

 a.      唯一標識字段名稱爲"ID",類型爲Int

 b.       名稱爲"Description"VarChar類型的字段,字段長度爲50

 c.      名稱爲"Data" varbinary(Max) 類型的字段。

2.      啓動 Visual Studio .NET 並創建一個新的 Visual C# Windows 應用程序項目。

3.      從工具欄中拖兩個Button 控件到默認窗體, Form1

4.      在屬性窗口中修改NamebuttonFileToDB Text 屬性爲從文件保存到數據庫 然後修改NamebuttonDBToFile Text 屬性爲從數據庫保存到文件

 

源碼實例

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Windows.Forms;

using System.Data.SqlClient;

using System.IO;

using System.Collections;

using System.Runtime.Serialization.Formatters.Binary;

 

//數據庫說明:MyTest數據庫,RWTest,包含3列:ID(int),Description(varchar(50), Data(varbinary(max))

 

namespace RWArrayListSQL

{

    public partial class Form1 : Form

    {

        ArrayList arrayList = new ArrayList();

        public Form1()

        {

            InitializeComponent();

            for (int i = 0; i < 100; i++)

            {

                PTData ptData = new PTData();

                ptData.PTID = i + 1;

                ptData.PTName = Convert.ToString(i + 1);

                ptData.PT_Data = i + 1;

                arrayList.Add(ptData);

            }

        }

 

        private void buttonFileToDB_Click(object sender, EventArgs e)

        {

                SqlConnection sqlConnection = new SqlConnection("Data Source=liuxueqin;Initial Catalog=MyTest;Integrated Security=True");               

                SqlDataAdapter sqlDataAdapter = new SqlDataAdapter("Select * from RWTest", sqlConnection);

                SqlCommandBuilder sqlCommandBuilder = new SqlCommandBuilder(sqlDataAdapter);

                System.Data.DataSet dataSet = new DataSet("RWTest");

                sqlDataAdapter.MissingSchemaAction = MissingSchemaAction.AddWithKey;//確定現有 DataSet 架構與傳入數據不匹配時需要執行的操作。

                //定義一個流

                Stream stream = new MemoryStream();

                //定義一個格式化器

                BinaryFormatter bf = new BinaryFormatter();

                foreach (object obj in arrayList)

                {

                    bf.Serialize(stream, obj);  //序列化

                }

                byte[] array = null;

                array = new byte[stream.Length];

                //將二進制流寫入數組

                stream.Position = 0;

                stream.Read(array, 0, (int)stream.Length);

                //關閉流

                stream.Close();

 

            try

            {

                sqlDataAdapter.Fill(dataSet, "RWTest");

                //DataRow表示DataTable中的一行數據

                System.Data.DataRow dataRow1;

                dataRow1 = dataSet.Tables["RWTest"].NewRow();

                dataRow1["ID"] = 1;

                dataRow1["Description"] = "This would be description text";               

                dataRow1["Data"] = array;

 

                dataSet.Tables["RWTest"].Rows.Add(dataRow1);

                sqlDataAdapter.Update(dataSet, "RWTest");

                sqlConnection.Close();

                MessageBox.Show("寫入數據庫成功!", " 信息提示", MessageBoxButtons.OK, MessageBoxIcon.Information);

            }

            catch (Exception ex)

            {

                if (sqlConnection.State == ConnectionState.Open)

                {

                    sqlConnection.Close();

                }

                MessageBox.Show("寫入數據庫失敗"+ex.Message, " 信息提示", MessageBoxButtons.OK, MessageBoxIcon.Error);

            }

        }

 

        private void buttonDBToFile_Click(object sender, EventArgs e)

        {

            SqlConnection sqlConnection = new SqlConnection("Data Source=liuxueqin;Initial Catalog=MyTest;Integrated Security=True");

            SqlDataAdapter sqlDataAdapter = new SqlDataAdapter("Select * from RWTest", sqlConnection);

            SqlCommandBuilder sqlCommandBuilder = new SqlCommandBuilder(sqlDataAdapter);

            DataSet dataSet = new DataSet("RWTest");

          

            sqlDataAdapter.Fill(dataSet, "RWTest");

            DataRow myRow;

            myRow = dataSet.Tables["RWTest"].Rows[0];

 

            byte[] b = null;

            b = (byte[])myRow["Data"];

            //定義一個流

            MemoryStream stream = new MemoryStream(b);

            //定義一個格式化器

            BinaryFormatter bf = new BinaryFormatter();           

            while (stream.Position != stream.Length)

            {

                arrayList.Add(bf.Deserialize(stream));  //反序列化

            }

            stream.Close();

 

            for(int i=0;i<5;i++) //信息提示,是否正確從數據庫中取出了ArrayList鏈表

            MessageBox.Show(((PTData)arrayList[i]).PTName, "信息提示", MessageBoxButtons.OK, MessageBoxIcon.Information);

 

            if (sqlConnection.State == ConnectionState.Open)

            {

                sqlConnection.Close();

            }

            MessageBox.Show(" 從數據庫讀出數據成功!", " 信息提示", MessageBoxButtons.OK, MessageBoxIcon.Information);

        }

}

 

    //在類的上面增加了屬性:Serializable.(如果不加這個屬性,將拋出SerializationException異常)。在不繼承自接口ISerializable的情況下,通過增加[Serializable]屬性可以允許該類可以被序列化。

    [Serializable]

    class PTData

    {

        public PTData()

        {

            PTID = 1;

            PTName = "None";

            PT_Data = 1.0;

        }

        public int PTID;

        public string PTName;

        public double PT_Data;

    }

}

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