C# FileStream BeginRead

In this chapter you will learn:

1. Get to know FileStream.BeginRead
2. Syntax for FileStream.BeginRead
3. Parameter for FileStream.BeginRead
4. Returns for FileStream.BeginRead
5. Example - FileStream.BeginRead

Description

FileStream BeginRead Begins an asynchronous read operation. (Consider using ReadAsync instead; see the Remarks section.)

Syntax

FileStream.BeginRead has the following syntax.

[HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)]
public override IAsyncResult BeginRead(
  byte[] array,//from  ww w.java  2 s .c om
  int offset,
  int numBytes,
  AsyncCallback userCallback,
  Object stateObject
)

Parameters

FileStream.BeginRead has the following parameters.

• array - The buffer to read data into.
• offset - The byte offset in array at which to begin reading.
• numBytes - The maximum number of bytes to read.
• userCallback - The method to be called when the asynchronous read operation is completed.
• stateObject - A user-provided object that distinguishes this particular asynchronous read request from other requests.

Returns

FileStream.BeginRead method returns An object that references the asynchronous read.

Example

/*from w ww .j  av  a  2 s.  co m*/
using System;
public class MainClass{
  public static void Main(String[] argv){  
     System.Console.WriteLine();
  }
  static void EndWriteCallback(IAsyncResult asyncResult)
  {
     State tempState = (State)asyncResult.AsyncState;
     FileStream fStream = tempState.FStream;
     fStream.EndWrite(asyncResult);
    
     fStream.Position = 0;
     asyncResult = fStream.BeginRead(
         tempState.ReadArray, 0 , tempState.ReadArray.Length, 
         new AsyncCallback(EndReadCallback), tempState);
    
  }
  
}

Next chapter...

What you will learn in the next chapter:

1. Get to know FileStream.BeginWrite
2. Syntax for FileStream.BeginWrite
3. Parameter for FileStream.BeginWrite
4. Returns for FileStream.BeginWrite
5. Example - FileStream.BeginWrite

C# FileStream BeginRead