EndWrite Method

FileStream.EndWrite Method (IAsyncResult)


Ends an asynchronous write operation and blocks until the I/O operation is complete. (Consider using WriteAsync instead; see the Remarks section.)

Namespace:   System.IO
Assembly:  mscorlib (in mscorlib.dll)

public override void EndWrite(
	IAsyncResult asyncResult


Type: System.IAsyncResult

The pending asynchronous I/O request.

Exception Condition

asyncResult is null.


This IAsyncResult object was not created by calling BeginWrite on this class.


EndWrite is called multiple times.


The stream is closed or an internal error has occurred.

In the .NET Framework 4 and earlier versions, you have to use methods such as BeginWrite and EndWrite to implement asynchronous file operations. These methods are still available in the .NET Framework 4.5 to support legacy code; however, the new async methods, such as ReadAsync, WriteAsync, CopyToAsync, and FlushAsync, help you implement asynchronous file operations more easily.

This method overrides EndWrite.

EndWrite must be called exactly once on every IAsyncResult from BeginWrite. EndWrite will block until the I/O operation has completed.

This code example is part of a larger example provided for the FileStream(String, FileMode, FileAccess, FileShare, Int32, Boolean) constructor.

static void EndWriteCallback(IAsyncResult asyncResult)
    State tempState = (State)asyncResult.AsyncState;
    FileStream fStream = tempState.FStream;

    // Asynchronously read back the written data.
    fStream.Position = 0;
    asyncResult = fStream.BeginRead(
        tempState.ReadArray, 0 , tempState.ReadArray.Length, 
        new AsyncCallback(EndReadCallback), tempState);

    // Concurrently do other work, such as 
    // logging the write operation.

.NET Framework
Available since 1.1
Available since 2.0
Windows Phone Silverlight
Available since 7.0
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