使用C#在數據庫中存取文件

╰半橙微兮° 2022-08-25 08:08 107阅读 0赞

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][http_www.cnblogs.com_jhtchina_archive_2006_03_03_341850.html]

[http_www.cnblogs.com_jhtchina_archive_2006_03_03_341850.html]: http://www.cnblogs.com/jhtchina/archive/2006/03/03/341850.html