) C # copy a large file using filestream

That is, a small segment of the file is copied each time to save the total memory overhead. Of course, local replication can also adopt the system. Io. file. COPY method in. net.

/// <Summary>

/// Copy an object

/// </Summary>

/// <Param name = "fromfile"> file to be copied </param>

/// <Param name = "tofile"> location to be saved </param>

/// <Param name = "lengtheachtime"> length of each copy </param>

Private void copyfile (string fromfile, string tofile, int lengtheachtime)

{

Filestream filetocopy = new filestream (fromfile, filemode. Open, fileaccess. Read );

Filestream copytofile = new filestream (tofile, filemode. append, fileaccess. Write );

Int lengthtocopy;

If (lengtheachtime <filetocopy. Length) // If multipart copy is performed, the content of each copy is smaller than the total length of the file.

{

Byte [] buffer = new byte [lengtheachtime];

Int copied = 0;

While (copied <= (INT) filetocopy. Length-lengtheachtime) // copy the subject part

{

Lengthtocopy = filetocopy. Read (buffer, 0, lengtheachtime );

Filetocopy. Flush ();

Copytofile. Write (buffer, 0, lengtheachtime );

Copytofile. Flush ();

Copytofile. Position = filetocopy. position;

Copied + = lengthtocopy;

}

Int left = (INT) filetocopy. Length-copied; // copy the remaining part

Lengthtocopy = filetocopy. Read (buffer, 0, left );

Filetocopy. Flush ();

Copytofile. Write (buffer, 0, left );

Copytofile. Flush ();

}

Else // if the overall copy, that is, the content of each copy is greater than the total length of the file

{

Byte [] buffer = new byte [filetocopy. Length];

Filetocopy. Read (buffer, 0, (INT) filetocopy. Length );

Filetocopy. Flush ();

Copytofile. Write (buffer, 0, (INT) filetocopy. Length );

Copytofile. Flush ();

}

Filetocopy. Close ();

Copytofile. Close ();

}