IsolatedStorageFileStream.BeginWrite Method

May 11, 2014

Begins an asynchronous write.

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

public override IAsyncResult BeginWrite(
	byte[] buffer,
	int offset,
	int numBytes,
	AsyncCallback userCallback,
	Object stateObject
)

Parameters

buffer
Type: System.Byte []
The buffer to write data to.
offset
Type: System.Int32
The byte offset in buffer at which to begin writing.
numBytes
Type: System.Int32
The maximum number of bytes to write.
userCallback
Type: System.AsyncCallback
The method to call when the asynchronous write operation is completed. This parameter is optional.
stateObject
Type: System.Object
The status of the asynchronous write.

Return Value

Type: System.IAsyncResult
An IAsyncResult that represents the asynchronous write, which is possibly still pending. This IAsyncResult must be passed to this stream's EndWrite method to ensure that the write is complete, then frees resources appropriately. This can be done either by the same code that called BeginWrite or in a callback passed to BeginWrite.

ExceptionCondition
IsolatedStorageException

The isolated store has been removed.

-or-

Isolated storage is disabled.

ArgumentException

The buffer length minus offset is less than numBytes.

ArgumentNullException

buffer is null.

ArgumentOutOfRangeException

offset or numBytes is negative.

IOException

An asynchronous read was attempted past the end of the file.

ObjectDisposedException

The stream has been disposed.

If a IsolatedStorageFileStream object is writable, writing at the end of the stream expands the stream.

The current position in the stream is updated when you issue the asynchronous read or write, not when the I/O operation completes.

You must call EndWrite with the IAsyncResult object that this method returns to find out how many bytes were written.

Version Notes

Windows Phone

 When this method is called within a Windows Phone application, the operation is executed synchronously. If you have to write a large amount of data and do not want to interrupt the UI thread, you can create a new thread and perform the operation on that thread.

Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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