How to load entire stream into MemoryStream?

问题:

Like in the topic: I want to read data from a file (from stream) into memory (memorystream) to improve my app speed. How to do it?

回答1:

A few options:

Read it all into a byte array first...

byte[] data = File.ReadAllBytes(file);
MemoryStream stream = new MemoryStream(data);

Or use .NET 4's CopyTo method

MemoryStream memoryStream = new MemoryStream();
using (Stream input = File.OpenRead(file))
{
    input.CopyTo(memoryStream);
}
memoryStream.Position = 0;

Or do it manually

MemoryStream memoryStream = new MemoryStream();
using (Stream input = File.OpenRead(file))
{
    byte[] buffer = new byte[32 * 1024]; // 32K buffer for example
    int bytesRead;
    while ((bytesRead = input.Read(buffer, 0, buffer.Length)) > 0)
    {
        memoryStream.Write(buffer, 0, bytesRead);
    }
}
memoryStream.Position = 0;

回答2:

If you can hold the entire file in memory, File.ReadAllBytes should work for you:

using (var ms = new MemoryStream(File.ReadAllBytes(file)))
{
    // do work
}