PipeStream.Read 方法

参考

定义

命名空间:: System.IO.Pipes

程序集:: System.IO.Pipes.dll

程序集:: netstandard.dll

程序集:: System.Core.dll

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。

重载

Read(Span<Byte>)	从当前流中读取一个字节序列，将其写入字节数组，并按读取的字节数向前移动流中的位置。
Read(Byte[], Int32, Int32)	从指定长度的指定位置开始，从流中读取一个字节块，并将数据写入指定的缓冲区。

Read(Span<Byte>)

Source:: PipeStream.Unix.cs

Source:: PipeStream.Unix.cs

Source:: PipeStream.Unix.cs

从当前流中读取一个字节序列，将其写入字节数组，并按读取的字节数向前移动流中的位置。

public:
 override int Read(Span<System::Byte> buffer);

public override int Read (Span<byte> buffer);

override this.Read : Span<byte> -> int

Public Overrides Function Read (buffer As Span(Of Byte)) As Integer

参数

buffer: Span<Byte>

内存的区域。当此方法返回时，此区域的内容将替换为从当前源读取的字节。

Int32

读入 buffer 中的总字节数。如果很多字节当前不可用，则这可小于在 buffer 中分配的字节数；如果已到达流结尾，则为零 (0)。

例外

ArgumentNullException

读取的字节数长于缓冲区长度。

NotSupportedException

流不支持读取。

ObjectDisposedException

无法访问关闭的管道。

InvalidOperationException

管道尚未连接。

- 或 -

管道处于断开连接状态。

- 或 -

尚未设置管道句柄。（你的 PipeStream 实现是否调用 InitializeHandle(SafePipeHandle, Boolean, Boolean)？

注解

CanRead使用属性可确定当前PipeStream对象是否支持读取操作。

ReadAsync使用方法从当前流异步读取。

此方法从当前流中读取最大 buffer.Length 字节数，并将其存储在中 buffer。流中的当前位置按读取的字节数提前;但是，如果发生异常，流中的当前位置保持不变。

如果没有任何数据可用，此方法将阻止，直到至少可以读取一个字节的数据。

仅当流中没有更多数据且预期不再 (（如关闭的套接字或文件) 结束）时，此方法才返回 0。

此方法可以自由返回比请求的字节少，即使尚未到达流的末尾。

用于 BinaryReader 读取基元数据类型。

适用于

Read(Byte[], Int32, Int32)

Source:: PipeStream.Unix.cs

Source:: PipeStream.Unix.cs

Source:: PipeStream.Unix.cs

从指定长度的指定位置开始，从流中读取一个字节块，并将数据写入指定的缓冲区。

public:
 override int Read(cli::array <System::Byte> ^ buffer, int offset, int count);

public override int Read (byte[] buffer, int offset, int count);

[System.Security.SecurityCritical]
public override int Read (byte[] buffer, int offset, int count);

override this.Read : byte[] * int * int -> int

[<System.Security.SecurityCritical>]
override this.Read : byte[] * int * int -> int

Public Overrides Function Read (buffer As Byte(), offset As Integer, count As Integer) As Integer

参数

buffer: Byte[]

当此方法返回时，包含指定的字节数组，此数组中 offset 和 (offset + count - 1) 之间的值被从当前源中读取的字节所替换。

offset: Int32

buffer 数组中的字节偏移量，其中读取的字节将被替换。

count: Int32

最多读取的字节数。

Int32

读取到 buffer 的总字节数。如果当前可用的字节数没有请求的那么多，则此数小于请求的字节数；或如果已到达流的末尾，则为零。

属性: SecurityCriticalAttribute

例外

ArgumentNullException

buffer 为 null。

ArgumentOutOfRangeException

offset 小于 0。

或

count 小于 0。

ArgumentException

count 大于 buffer 中可用的字节数。

ObjectDisposedException

管道已关闭。

NotSupportedException

管道不支持读操作。

InvalidOperationException

管道已断开连接、正在等待连接或尚未设置句柄。

IOException

发生了 I/O 错误。

示例

以下示例创建匿名管道客户端和管道服务器。管道服务器使用 Read 方法从管道客户端读取一系列字节作为验证代码。管道客户端和管道服务器都是同一示例的一部分。示例的服务器部分创建一个客户端进程，并向其传递一个匿名管道句柄作为参数。

#using <System.dll>
#using <System.Core.dll>

using namespace System;
using namespace System::IO;
using namespace System::IO::Pipes;
using namespace System::Diagnostics;

ref class PipeStreamExample
{
private:
    static array<Byte>^ matchSign = {9, 0, 9, 0};

public:
    static void Main()
    {
        array<String^>^ args = Environment::GetCommandLineArgs();
        if (args->Length < 2)
        {
            Process^ clientProcess = gcnew Process();

            clientProcess->StartInfo->FileName = Environment::CommandLine;

            AnonymousPipeServerStream^ pipeServer =
                gcnew AnonymousPipeServerStream(PipeDirection::In,
                HandleInheritability::Inheritable);
            // Pass the client process a handle to the server.
            clientProcess->StartInfo->Arguments = pipeServer->GetClientHandleAsString();
            clientProcess->StartInfo->UseShellExecute = false;
            Console::WriteLine("[SERVER] Starting client process...");
            clientProcess->Start();

            pipeServer->DisposeLocalCopyOfClientHandle();

            try
            {
                if (WaitForClientSign(pipeServer))
                {
                    Console::WriteLine("[SERVER] Valid sign code received!");
                }
                else
                {
                    Console::WriteLine("[SERVER] Invalid sign code received!");
                }
            }
            catch (IOException^ e)
            {
                 Console::WriteLine("[SERVER] Error: {0}", e->Message);
            }
            clientProcess->WaitForExit();
            clientProcess->Close();
            Console::WriteLine("[SERVER] Client quit. Server terminating.");
        }
        else
        {
            PipeStream^ pipeClient =
                gcnew AnonymousPipeClientStream(PipeDirection::Out, args[1]);
            try
            {
                Console::WriteLine("[CLIENT] Sending sign code...");
                SendClientSign(pipeClient);
            }
            catch (IOException^ e)
            {
                Console::WriteLine("[CLIENT] Error: {0}", e->Message);
            }
            Console::WriteLine("[CLIENT] Terminating.");
        }
    }

private:
    static bool WaitForClientSign(PipeStream^ inStream)
    {
        array<Byte>^ inSign = gcnew array<Byte>(matchSign->Length);
        int len = inStream->Read(inSign, 0, matchSign->Length);
        bool valid = len == matchSign->Length;

        while (valid && len-- > 0)
        {
            valid = valid && (matchSign[len] == inSign[len]);
        }
        return valid;
    }

    static void SendClientSign(PipeStream^ outStream)
    {
        outStream->Write(matchSign, 0, matchSign->Length);
    }
};

int main()
{
    PipeStreamExample::Main();
}

using System;
using System.IO;
using System.IO.Pipes;
using System.Diagnostics;

class PipeStreamExample
{
    private static byte[] matchSign = {9, 0, 9, 0};

    public static void Main()
    {
        string[] args = Environment.GetCommandLineArgs();
        if (args.Length < 2)
        {
            Process clientProcess = new Process();

            clientProcess.StartInfo.FileName = Environment.CommandLine;

            using (AnonymousPipeServerStream pipeServer =
                new AnonymousPipeServerStream(PipeDirection.In,
                HandleInheritability.Inheritable))
            {
                // Pass the client process a handle to the server.
                clientProcess.StartInfo.Arguments = pipeServer.GetClientHandleAsString();
                clientProcess.StartInfo.UseShellExecute = false;
                Console.WriteLine("[SERVER] Starting client process...");
                clientProcess.Start();

                pipeServer.DisposeLocalCopyOfClientHandle();

                try
                {
                    if (WaitForClientSign(pipeServer))
                    {
                        Console.WriteLine("[SERVER] Valid sign code received!");
                    }
                    else
                    {
                        Console.WriteLine("[SERVER] Invalid sign code received!");
                    }
                }
                catch (IOException e)
                {
                    Console.WriteLine("[SERVER] Error: {0}", e.Message);
                }
            }
            clientProcess.WaitForExit();
            clientProcess.Close();
            Console.WriteLine("[SERVER] Client quit. Server terminating.");
        }
        else
        {
            using (PipeStream pipeClient = new AnonymousPipeClientStream(PipeDirection.Out, args[1]))
            {
                try
                {
                    Console.WriteLine("[CLIENT] Sending sign code...");
                    SendClientSign(pipeClient);
                }
                catch (IOException e)
                {
                     Console.WriteLine("[CLIENT] Error: {0}", e.Message);
                }
            }
            Console.WriteLine("[CLIENT] Terminating.");
        }
    }

    private static bool WaitForClientSign(PipeStream inStream)
    {
        byte[] inSign = new byte[matchSign.Length];
        int len = inStream.Read(inSign, 0, matchSign.Length);
        bool valid = len == matchSign.Length;

        while (valid && len-- > 0)
        {
            valid = valid && (matchSign[len] == inSign[len]);
        }
        return valid;
    }

    private static void SendClientSign(PipeStream outStream)
    {
        outStream.Write(matchSign, 0, matchSign.Length);
    }
}

Imports System.IO
Imports System.IO.Pipes
Imports System.Diagnostics

Class PipeStreamExample
    Private Shared matchSign() As Byte = {9, 0, 9, 0}

    Public Shared Sub Main()
        Dim args() As String = Environment.GetCommandLineArgs()
        If args.Length < 2 Then
            Dim clientProcess As New Process()

            clientProcess.StartInfo.FileName = Environment.CommandLine

            Using pipeServer As New AnonymousPipeServerStream( _
                PipeDirection.In, HandleInheritability.Inheritable)

                ' Pass the client process a handle to the server.
                clientProcess.StartInfo.Arguments = pipeServer.GetClientHandleAsString()
                clientProcess.StartInfo.UseShellExecute = false
                Console.WriteLine("[SERVER] Starting client process...")
                clientProcess.Start()

                pipeServer.DisposeLocalCopyOfClientHandle()

                Try
                    If WaitForClientSign(pipeServer) Then
                        Console.WriteLine("[SERVER] Valid sign code received!")
                    Else
                        Console.WriteLine("[SERVER] Invalid sign code received!")
                    End If
                Catch e As IOException
                    Console.WriteLine("[SERVER] Error: {0}", e.Message)
                End Try
            End Using
            clientProcess.WaitForExit()
            clientProcess.Close()
            Console.WriteLine("[SERVER] Client quit. Server terminating.")
        Else
            Using pipeClient As PipeStream = New AnonymousPipeClientStream(PipeDirection.Out, args(1))
                Try
                    Console.WriteLine("[CLIENT] Sending sign code...")
                    SendClientSign(pipeClient)
                Catch e As IOException
                    Console.WriteLine("[CLIENT] Error: {0}", e.Message)
                End Try
            End Using
            Console.WriteLine("[CLIENT] Terminating.")
        End If
    End Sub

    Private Shared Function WaitForClientSign(inStream As PipeStream) As Boolean
        Dim inSign() As Byte = Array.CreateInstance(GetType(Byte), matchSign.Length)
        Dim len As Integer = inStream.Read(inSign, 0, matchSign.Length)
        Dim valid = len.Equals(matchSign.Length)

        While len > 0
            len -= 1
            valid = valid And (matchSign(len).Equals(inSign(len)))
        End While
        Return valid
    End Function

    Private Shared Sub SendClientSign(outStream As PipeStream)
        outStream.Write(matchSign, 0, matchSign.Length)
    End Sub
End Class

注解

CanRead使用属性可确定当前PipeStream对象是否支持读取操作。

调用方法将 Read 阻止，直到 count 读取字节或到达流的末尾。有关异步读取操作，请参阅 BeginRead 和 EndRead。

适用于

PipeStream.Read 方法

定义

重载

Read(Span<Byte>)

参数

返回

例外

注解

适用于

Read(Byte[], Int32, Int32)

参数

返回

例外

示例

注解

适用于

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