使用C#在數據庫中存取文件

使用C#在數據庫中存取文件

 

將文件保存到數據庫中的操作,一般有以下幾個步驟:
1.把文件轉化為字節數組
2.將字節數組存入數據庫
3.從數據庫中讀出字節數組
4.將字節數組轉化成相應的文件等,並作進一步的操作

1.把文件轉化為字節數組 

// 將文件轉化為二进制流byte[] 
private   byte [] FileToStream( string  fileName)
{
 FileInfo fi = new  FileInfo(fileName);
 FileStream fs = fi.OpenRead();
  byte [] bytes = new   byte [fs.Length];
 fs.Read(bytes, 0 ,Convert.ToInt32(fs.Length));
  return  bytes;
}

 

        // 把图片文件转化为二进制流byte[] 
         private   byte [] ImageToStream( string  fileName)
        {
            Bitmap image  =   new  Bitmap(fileName);
            MemoryStream stream  =   new  MemoryStream();
            image.Save(stream, System.Drawing.Imaging.ImageFormat.Bmp);
             return  stream.ToArray();
        }

2.將字節數組byte[]存入數據庫

         private   void  StoreImage( byte [] byt)
        {
                 string  str_Conn = " server=SERVER-DBT;database=LogERP;uid=logerp;pwd=logerpok; " ;
                SqlConnection sqlconn = new  SqlConnection(str_Conn);

                SqlCommand cmd  =   new  SqlCommand( " Insert into ENTR_Image(EImage) values (@EImage) " );
                cmd.Connection = sqlconn;
                SqlParameter imageParameter  =  cmd.Parameters.Add( " @EImage " , SqlDbType.Binary);
                imageParameter.Value  =  byt;
                imageParameter.Size   =  byt.Length;

        sqlconn.Open();
                cmd.ExecuteNonQuery();                
                sqlconn.Close();
        } 

3.從數據庫中讀出字節數組

         public   static   byte [] GetByteImage( string  str_Sql)
        {            
             string  connectionString  =  System.Configuration.ConfigurationSettings.AppSettings[ " ConnStr " ].ToString();
             byte  [] content = {};
            SqlConnection sqlconn = new  SqlConnection(connectionString);
            sqlconn.Open();            
            SqlCommand cmd = new  SqlCommand(str_Sql);
            cmd.Connection = sqlconn;
            content  =  ( byte [] )cmd.ExecuteScalar();
            sqlconn.Close();
             return  content;
        }

4.將字節數組轉化成相應的文件等,並作進一步的操作

         //  根据2进制数组获得文件並保存
         private   void  GetFileFromDataBase( byte [] byt, string  str_Filename)
        {
            FileStream fs_stream = new  FileStream(str_Filename,FileMode.CreateNew);
            BinaryWriter writefile  =   new  BinaryWriter(fs_stream);
            writefile.Write(byt);
            writefile.Close();            
        }

 

//  根据2进制数组获得圖片
private  Image GetImage( byte [] byt)
{
    MemoryStream stream  =   new  MemoryStream(byt);
     return  Image.FromStream(stream); 
}

 

參考文獻: 1. http://www.cnblogs.com/jhtchina/archive/2006/03/03/341850.html