sql server表结构如下：

create table DataTable(Id int identity(1,1) not null primary key,FileName nvarchar(100) not null,FilePath nvarchar(200) not null,Data varbinary(MAX) )

主要方法：

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.IO;using System.Data;using System.Data.SqlClient;using System.Windows.Forms;using System.Drawing;namespace DataAccess{    public class PubFunction    {        /// 
        /// 把文件存入数据库        /// 
        /// 文件路径（含文件名）        /// 
    
     存入是否成功
            public static bool StoreFiles(string[] filePaths)        {            try            {                for (int i = 0; i < filePaths.Length; i++)                {                    string filePath = filePaths[i];                    string fileName = filePath.Substring(filePath.LastIndexOf("\\") + 1);                    using (SqlConnection connection = new SqlConnection(PubVariant.ConnectionString))                    {                        connection.Open();                        FileStream pFileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);                        byte[] bytes = new byte[pFileStream.Length];                        pFileStream.Read(bytes, 0, (int)pFileStream.Length);                        string strSql = "insert into DataTable(FileName,FilePath,Data) values(@FileName,@FilePath,@Data)";                        using (SqlCommand cmd = new SqlCommand(strSql, connection))                        {                            cmd.Parameters.Add("@FileName", SqlDbType.Text);                            cmd.Parameters.Add("@FilePath", SqlDbType.Text);                            cmd.Parameters.Add("@Data", SqlDbType.Binary);                            cmd.Parameters["@FileName"].Value = fileName;                            cmd.Parameters["@FilePath"].Value = filePath;                            cmd.Parameters["@Data"].Value = bytes;                            cmd.ExecuteNonQuery();                        }                    }                }                return true;            }            catch (Exception ex)            {                MessageBox.Show(ex.Message);                return false;            }                    }        /// 
        /// 将数据库中数据写入文件        /// 
        /// 用于查找数据的文件名        /// 目标文件路径（含文件名）        /// 
    
     写入是否成功
            public static bool WriteFromDBtoFile(string fileName, string destFilePath)        {            FileStream pFileStream = null;            try            {                using (SqlConnection connection = new SqlConnection(PubVariant.ConnectionString))                {                    connection.Open();                    string strSql0 = "select Data from DataTable where FileName = '{0}'";                    string strSql1 = String.Format(strSql0, fileName);                    SqlCommand cmd = new SqlCommand(strSql1, connection);                    SqlDataReader dr = cmd.ExecuteReader();                    dr.Read();                    byte[] bytes = (byte[])dr[0];                    pFileStream = new FileStream(destFilePath, FileMode.OpenOrCreate, FileAccess.ReadWrite);                    pFileStream.Write(bytes, 0, bytes.Length);                }                return true;            }            catch (Exception ex)            {                MessageBox.Show(ex.Message);                return false;            }            finally            {                if (pFileStream != null)                {                    pFileStream.Close();                }            }        }        public static DataTable GetDataFromSql(string strSql)        {            using (SqlConnection connection = new SqlConnection(PubVariant.ConnectionString))            {                using (SqlCommand cmd = new SqlCommand(strSql, connection))                {                    using (SqlDataAdapter da = new SqlDataAdapter(cmd))                    {                        using (DataSet ds = new DataSet())                        {                            da.Fill(ds);                            DataTable dt = ds.Tables[0];                            return dt;                        }                    }                }            }        }    }}

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;using System.IO;using System.Data.SqlClient;namespace DataAccess{    public partial class Form1 : Form    {        public Form1()        {            InitializeComponent();        }        private void textBox1_MouseClick(object sender, MouseEventArgs e)        {            OpenFileDialog ofd = new OpenFileDialog();            ofd.Multiselect = true;            ofd.InitialDirectory = "F:\\";            ofd.Filter = "All files(*.*)|*.*";            ofd.Title = "选择文件";            ofd.ShowDialog();            PubVariant.filePaths = ofd.FileNames;            listBox1.DataSource = PubVariant.filePaths;        }        private void btnSave_Click(object sender, EventArgs e)        {            if(PubFunction.StoreFiles(PubVariant.filePaths))            {                MessageBox.Show("Succeed!");            }        }        private void textBox2_MouseClick(object sender, MouseEventArgs e)        {            SaveFileDialog sfd = new SaveFileDialog();            sfd.Filter = "All files(*.*)|*.*";            sfd.Title = "保存文件";            sfd.InitialDirectory = "F:\\";            sfd.FileName = comboBox1.Text;            sfd.ShowDialog();            textBox2.Text = sfd.FileName;            PubVariant.saveFilePath = sfd.FileName;        }        private void button1_Click(object sender, EventArgs e)        {            string fileName = comboBox1.Text;            if(PubFunction.WriteFromDBtoFile(fileName,PubVariant.saveFilePath))            {                MessageBox.Show("Succeed!");            }        }        private void comboBox1_MouseClick(object sender, MouseEventArgs e)        {            string strSql = "select FileName from DataTable";            DataTable dt = PubFunction.GetDataFromSql(strSql);            for (int i = 0; i < dt.Rows.Count; i++)            {                comboBox1.Items.Add(dt.Rows[i][0].ToString());            }        }    }}

public class PubVariant    {        public static string[] filePaths;        public static string saveFilePath;        public static string connectionString = "server=eagle;database=Test;user id = sa;password=123456";        public static string ConnectionString        {            get { return connectionString; }            set { connectionString = value; }        }    }

转载：http://blog.csdn.net/foreverling/article/details/37691273