C#存取SQL Server數據庫之一：二進制存取圖片文件

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"的VarChar類型的字段，字段長度爲50。

 c.      名稱爲"ImgField" 的Image 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Name爲buttonFileToDB， Text 屬性爲從文件保存到數據庫， 然後修改Name爲buttonDBToFile ，Text 屬性爲從數據庫保存到文件。

5 從工具欄放置2個TextBox和1個PictureBox控件：Name屬性分別爲：textBoxGetID,           textBoxGetDescription, pictureBoxGetImage, 顯示從數據庫讀出的ID，Description，ImgField字段。

 

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;

//數據庫說明：MyTest數據庫，RWTest表,包含3列：ID(int),Description(varchar(50),ImgField(Image)

 

namespace RWImgSQL

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        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);

            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。

 

            String CurrentExeName = System.Diagnostics.Process.GetCurrentProcess().MainModule.FileName;

            string ImageFile = System.IO.Path.GetDirectoryName(CurrentExeName) + "//F1.jpg";

            System.IO.FileStream fileStream = new FileStream(ImageFile, FileMode.OpenOrCreate, FileAccess.ReadWrite);

            byte[] myData = new byte[fileStream.Length];

            fileStream.Read(myData, 0, System.Convert.ToInt32(fileStream.Length));//從流中讀取字節塊，並將數據寫入到該緩衝區

            fileStream.Close();

            try

            {

                sqlDataAdapter.Fill(dataSet, "RWTest");

                //DataRow表示DataTable中的一行數據

                System.Data.DataRow dataRow;

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

                dataRow1["ID"] = 1;

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

                dataRow1["ImgField"] = myData;

 

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

                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");

 

            byte[] MyData = new byte[0];

            sqlDataAdapter.Fill(dataSet, "RWTest");

            DataRow myRow;

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

            MyData = (byte[])myRow["imgField"];

 

            int ArraySize = MyData.GetUpperBound(0);

            String CurrentExeName = System.Diagnostics.Process.GetCurrentProcess().MainModule.FileName;

            string ImageFile = System.IO.Path.GetDirectoryName(CurrentExeName) + "//F2.jpg";

            FileStream fs = new FileStream(ImageFile, FileMode.OpenOrCreate, FileAccess.Write);

            fs.Write(MyData, 0, ArraySize);

            fs.Close();

 

            //---在界面上的2個textBox和1個pictureBox，用來顯示從數據庫中讀出的ID，Description，ImageField字段

            textBoxGetID.Text = myRow["ID"].ToString();

            textBoxGetDescription.Text = myRow["Description"].ToString();

            pictureBoxGetImage.Image = Image.FromFile(ImageFile);

 

            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);

        }

}

}