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

定义

命名空间:

System.IO

程序集:

System.Runtime.dll

程序集:

netstandard.dll

程序集:

mscorlib.dll

开始异步读操作。 请考虑改用 ReadAsync(Byte[], Int32, Int32, CancellationToken)。

public:
 override IAsyncResult ^ BeginRead(cli::array <System::Byte> ^ array, int offset, int numBytes, AsyncCallback ^ callback, System::Object ^ state);

public:
 override IAsyncResult ^ BeginRead(cli::array <System::Byte> ^ buffer, int offset, int count, AsyncCallback ^ callback, System::Object ^ state);

public:
 override IAsyncResult ^ BeginRead(cli::array <System::Byte> ^ array, int offset, int numBytes, AsyncCallback ^ userCallback, System::Object ^ stateObject);

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);

override this.BeginRead : byte[] * int * int * AsyncCallback * obj -> IAsyncResult

override this.BeginRead : byte[] * int * int * AsyncCallback * obj -> IAsyncResult

override this.BeginRead : byte[] * int * int * AsyncCallback * obj -> IAsyncResult

Public Overrides Function BeginRead (array As Byte(), offset As Integer, numBytes As Integer, callback As AsyncCallback, state As Object) As IAsyncResult

Public Overrides Function BeginRead (buffer As Byte(), offset As Integer, count As Integer, callback As AsyncCallback, state As Object) As IAsyncResult

Public Overrides Function BeginRead (array As Byte(), offset As Integer, numBytes As Integer, userCallback As AsyncCallback, stateObject As Object) As IAsyncResult

参数

arraybuffer

Byte[]

将数据读入的缓冲区。

offset

Int32

array 中的字节偏移量，从此处开始读取。

numBytescount

Int32

最多读取的字节数。

callbackuserCallback

AsyncCallback

异步读操作完成后调用的方法。

statestateObject

Object

一个用户提供的对象，它将该特定的异步读取请求与其他请求区别开来。

返回

IAsyncResult

引用异步读取的对象。

例外

ArgumentException

数组长度减去 offset 小于 numBytes。

ArgumentNullException

array 为 null。

ArgumentOutOfRangeException

offset 或 numBytes 为负数。

IOException

尝试在文件的末尾后进行异步读取。