转 FileStream Read File

FileStream Read File [C#]

This example shows how to safely read file using FileStream in C#. To be sure the whole file is correctly read, you should call FileStream.Read method in a loop, even if in the most cases the whole file is read in a single call of FileStream.Read method.

Read file using FileStream

First create FileStream to open a file for reading. Then call FileStream.Read in a loop until the whole file is read. Finally close the stream.
[C#]

 1 using System.IO;
 2 public static byte[] ReadFile(string filePath)
 3 {
 4   byte[] buffer;
 5   FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);
 6   try
 7   {
 8     int length = (int)fileStream.Length;  // get file length
 9     buffer = new byte[length];            // create buffer
10     int count;                            // actual number of bytes read
11     int sum = 0;                          // total number of bytes read
12 
13 
14     // read until Read method returns 0 (end of the stream has been reached)
15     while ((count = fileStream.Read(buffer, sum, length - sum)) > 0)
16       sum += count;  // sum is a buffer offset for next reading
17   }
18   finally
19   {
20     fileStream.Close();
21   }
22   return buffer;
23 }