FileStream.BeginRead(Byte[], Int32, Int32, AsyncCallback, Object) 方法
重要
一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。 对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。
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);C#
public override IAsyncResult BeginRead (byte[] array, int offset, int numBytes, AsyncCallback? callback, object? state);C#
public override IAsyncResult BeginRead (byte[] buffer, int offset, int count, AsyncCallback? callback, object? state);C#
public override IAsyncResult BeginRead (byte[] buffer, int offset, int count, AsyncCallback callback, object state);C#
public override IAsyncResult BeginRead (byte[] array, int offset, int numBytes, AsyncCallback callback, object state);C#
public override IAsyncResult BeginRead (byte[] array, int offset, int numBytes, AsyncCallback callback, object? state);C#
public override IAsyncResult BeginRead (byte[] array, int offset, int numBytes, AsyncCallback userCallback, object stateObject);override this.BeginRead : byte[] * int * int * AsyncCallback * obj -> IAsyncResultoverride 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, numBytes As Integer, callback As AsyncCallback, state As Object) As IAsyncResultPublic Overrides Function BeginRead (buffer As Byte(), offset As Integer, count As Integer, callback As AsyncCallback, state As Object) As IAsyncResultPublic Overrides Function BeginRead (array As Byte(), offset As Integer, numBytes As Integer, userCallback As AsyncCallback, stateObject As Object) As IAsyncResult- 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。
引用异步读取的对象。
数组长度减去 offset 小于 numBytes。
array 为 null。
offset 或 numBytes 为负数。
尝试在文件的末尾后进行异步读取。
| 产品 | 版本 |
|---|---|
| .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 |
