GZipStream.BeginRead(Byte[], Int32, Int32, AsyncCallback, Object) Method
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Begins an asynchronous read operation. (Consider using the ReadAsync(Byte[], Int32, Int32) method instead.)
public:
override IAsyncResult ^ BeginRead(cli::array <System::Byte> ^ array, int offset, int count, AsyncCallback ^ asyncCallback, System::Object ^ asyncState);public:
override IAsyncResult ^ BeginRead(cli::array <System::Byte> ^ buffer, int offset, int count, AsyncCallback ^ asyncCallback, System::Object ^ asyncState);public override IAsyncResult BeginRead (byte[] array, int offset, int count, AsyncCallback? asyncCallback, object? asyncState);public override IAsyncResult BeginRead (byte[] buffer, int offset, int count, AsyncCallback? asyncCallback, object? asyncState);public override IAsyncResult BeginRead (byte[] array, int offset, int count, AsyncCallback asyncCallback, object asyncState);override this.BeginRead : byte[] * int * int * AsyncCallback * obj -> IAsyncResultoverride this.BeginRead : byte[] * int * int * AsyncCallback * obj -> IAsyncResultPublic Overrides Function BeginRead (array As Byte(), offset As Integer, count As Integer, asyncCallback As AsyncCallback, asyncState As Object) As IAsyncResultPublic Overrides Function BeginRead (buffer As Byte(), offset As Integer, count As Integer, asyncCallback As AsyncCallback, asyncState As Object) As IAsyncResultParameters
- arraybuffer
- Byte[]
The byte array to read the data into.
- offset
- Int32
The byte offset at which to begin reading data from the stream.
- count
- Int32
The maximum number of bytes to read.
- asyncCallback
- AsyncCallback
An optional asynchronous callback, to be called when the read operation is complete.
- asyncState
- Object
A user-provided object that distinguishes this particular asynchronous read request from other requests.
Returns
An object that represents the asynchronous read operation, which could still be pending.
Exceptions
The method tried to read asynchronously past the end of the stream, or a disk error occurred.
One or more of the arguments is invalid.
Methods were called after the stream was closed.
The current GZipStream implementation does not support the read operation.
A read operation cannot be performed because the stream is closed.
Remarks
Important
Starting in .NET 6, this method might not read as many bytes as were requested. For more information, see Partial and zero-byte reads in DeflateStream, GZipStream, and CryptoStream.
Starting with .NET Framework 4.5, you can perform asynchronous read operations by using the Stream.ReadAsync method. The BeginRead method is still available in current versions to support legacy code; however, you can implement asynchronous I/O operations more easily by using the new async methods. For more information, see Asynchronous file I/O.
Pass the IAsyncResult return value to the EndRead method of the stream to determine how many bytes were read and to release operating system resources used for reading. You can do this either by using the same code that called BeginRead or in a callback passed to BeginRead.
The current position in the stream is updated when the asynchronous read or write is issued, not when the I/O operation completes.
Multiple simultaneous asynchronous requests render the request completion order uncertain.
Use the CanRead property to determine whether the current GZipStream object supports reading.
If a stream is closed or you pass an invalid argument, exceptions are thrown immediately from BeginRead. Errors that occur during an asynchronous read request, such as a disk failure during the I/O request, occur on the thread pool thread and throw exceptions when calling EndRead.
