ReaderWriterLock.IsReaderLockHeld 属性
获取一个值,该值指示当前线程是否持有读线程锁。
**命名空间:**System.Threading
**程序集:**mscorlib(在 mscorlib.dll 中)
语法
声明
Public ReadOnly Property IsReaderLockHeld As Boolean
用法
Dim instance As ReaderWriterLock
Dim value As Boolean
value = instance.IsReaderLockHeld
public bool IsReaderLockHeld { get; }
public:
property bool IsReaderLockHeld {
bool get ();
}
/** @property */
public boolean get_IsReaderLockHeld ()
public function get IsReaderLockHeld () : boolean
属性值
如果当前线程持有读线程锁,则为 true;否则为 false。
示例
下面的代码示例阐释了如何使用 IsReaderLockHeld 以避免死锁。
Imports System
Imports System.Threading
Public Class LockHeld
<MTAThread> _
Shared Sub Main()
Dim rwLock As New ReaderWriterLock()
rwLock.AcquireWriterLock(Timeout.Infinite)
rwLock.AcquireReaderLock(Timeout.Infinite)
If rwLock.IsReaderLockHeld Then
Console.WriteLine("Reader lock held.")
rwLock.ReleaseReaderLock()
Else If rwLock.IsWriterLockHeld Then
Console.WriteLine("Writer lock held.")
rwLock.ReleaseWriterLock()
Else
Console.WriteLine("No locks held.")
End If
If rwLock.IsReaderLockHeld Then
Console.WriteLine("Reader lock held.")
rwLock.ReleaseReaderLock()
Else If rwLock.IsWriterLockHeld Then
Console.WriteLine("Writer lock held.")
rwLock.ReleaseWriterLock()
Else
Console.WriteLine("No locks held.")
End If
End Sub
End Class
using System;
using System.Threading;
class LockHeld
{
static void Main()
{
ReaderWriterLock rwLock = new ReaderWriterLock();
rwLock.AcquireWriterLock(Timeout.Infinite);
rwLock.AcquireReaderLock(Timeout.Infinite);
if(rwLock.IsReaderLockHeld)
{
Console.WriteLine("Reader lock held.");
rwLock.ReleaseReaderLock();
}
else if(rwLock.IsWriterLockHeld)
{
Console.WriteLine("Writer lock held.");
rwLock.ReleaseWriterLock();
}
else
{
Console.WriteLine("No locks held.");
}
if(rwLock.IsReaderLockHeld)
{
Console.WriteLine("Reader lock held.");
rwLock.ReleaseReaderLock();
}
else if(rwLock.IsWriterLockHeld)
{
Console.WriteLine("Writer lock held.");
rwLock.ReleaseWriterLock();
}
else
{
Console.WriteLine("No locks held.");
}
}
}
using namespace System;
using namespace System::Threading;
int main()
{
ReaderWriterLock^ rwLock = gcnew ReaderWriterLock;
rwLock->AcquireWriterLock( Timeout::Infinite );
rwLock->AcquireReaderLock( Timeout::Infinite );
if ( rwLock->IsReaderLockHeld )
{
Console::WriteLine( "Reader lock held." );
rwLock->ReleaseReaderLock();
}
else
if ( rwLock->IsWriterLockHeld )
{
Console::WriteLine( "Writer lock held." );
rwLock->ReleaseWriterLock();
}
else
{
Console::WriteLine( "No locks held." );
}
if ( rwLock->IsReaderLockHeld )
{
Console::WriteLine( "Reader lock held." );
rwLock->ReleaseReaderLock();
}
else
if ( rwLock->IsWriterLockHeld )
{
Console::WriteLine( "Writer lock held." );
rwLock->ReleaseWriterLock();
}
else
{
Console::WriteLine( "No locks held." );
}
}
import System.*;
import System.Threading.*;
class LockHeld
{
public static void main(String[] args)
{
ReaderWriterLock rwLock = new ReaderWriterLock();
rwLock.AcquireWriterLock(Timeout.Infinite);
rwLock.AcquireReaderLock(Timeout.Infinite);
if (rwLock.get_IsReaderLockHeld()) {
Console.WriteLine("Reader lock held.");
rwLock.ReleaseReaderLock();
}
else {
if (rwLock.get_IsWriterLockHeld()) {
Console.WriteLine("Writer lock held.");
rwLock.ReleaseWriterLock();
}
else {
Console.WriteLine("No locks held.");
}
}
if (rwLock.get_IsReaderLockHeld()) {
Console.WriteLine("Reader lock held.");
rwLock.ReleaseReaderLock();
}
else {
if (rwLock.get_IsWriterLockHeld()) {
Console.WriteLine("Writer lock held.");
rwLock.ReleaseWriterLock();
}
else {
Console.WriteLine("No locks held.");
}
}
} //main
} //LockHeld
平台
Windows 98、Windows 2000 SP4、Windows Millennium Edition、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition
.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表,请参见系统要求。
版本信息
.NET Framework
受以下版本支持:2.0、1.1、1.0
请参见
参考
ReaderWriterLock 类
ReaderWriterLock 成员
System.Threading 命名空间