FileStream.BeginRead(Byte[], Int32, Int32, AsyncCallback, Object) Method

Definition

Begins an asynchronous read operation. Consider using ReadAsync(Byte[], Int32, Int32, CancellationToken) instead.

public override IAsyncResult BeginRead (byte[] array, int offset, int numBytes, AsyncCallback? callback, object? state);
public override IAsyncResult BeginRead (byte[] buffer, int offset, int count, AsyncCallback? callback, object? state);
public override IAsyncResult BeginRead (byte[] buffer, int offset, int count, AsyncCallback callback, object state);
public override IAsyncResult BeginRead (byte[] array, int offset, int numBytes, AsyncCallback callback, object state);
public override IAsyncResult BeginRead (byte[] array, int offset, int numBytes, AsyncCallback callback, object? state);
public override IAsyncResult BeginRead (byte[] array, int offset, int numBytes, AsyncCallback userCallback, object stateObject);

Parameters

arraybuffer
Byte[]

The buffer to read data into.

offset
Int32

The byte offset in array at which to begin reading.

numBytescount
Int32

The maximum number of bytes to read.

callbackuserCallback
AsyncCallback

The method to be called when the asynchronous read operation is completed.

statestateObject
Object

A user-provided object that distinguishes this particular asynchronous read request from other requests.

Returns

An object that references the asynchronous read.

Exceptions

The array length minus offset is less than numBytes.

array is null.

offset or numBytes is negative.

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

Applies to

Product Versions
.NET Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 2.0, 2.1