Gets or sets a value indicating whether or not a thread is a background thread.
Assembly: mscorlib (in mscorlib.dll)
Public Property IsBackground As Boolean
public bool IsBackground { get; set; }
public: property bool IsBackground { bool get (); void set (bool value); }
member IsBackground : bool with get, set
Property Value
Type: System.Booleantrue if this thread is or is to become a background thread; otherwise, false.
| Exception | Condition |
|---|---|
| ThreadStateException |
The thread is dead. |
A thread is either a background thread or a foreground thread. Background threads are identical to foreground threads, except that background threads do not prevent a process from terminating. Once all foreground threads belonging to a process have terminated, the common language runtime ends the process. Any remaining background threads are stopped and do not complete.
The following code example contrasts the behavior of foreground and background threads. A foreground thread and a background thread are created. The foreground thread keeps the process running until it completes its while loop. After the foreground thread has finished, the process is terminated before the background thread has completed its while loop.
Imports System Imports System.Threading Public Class Test <MTAThread> _ Shared Sub Main() Dim shortTest As New BackgroundTest(10) Dim foregroundThread As New Thread(AddressOf shortTest.RunLoop) foregroundThread.Name = "ForegroundThread" Dim longTest As New BackgroundTest(50) Dim backgroundThread As New Thread(AddressOf longTest.RunLoop) backgroundThread.Name = "BackgroundThread" backgroundThread.IsBackground = True foregroundThread.Start() backgroundThread.Start() End Sub End Class Public Class BackgroundTest Dim maxIterations As Integer Sub New(maximumIterations As Integer) maxIterations = maximumIterations End Sub Sub RunLoop() Dim threadName As String = Thread.CurrentThread.Name For i As Integer = 0 To maxIterations Console.WriteLine("{0} count: {1}", _ threadName, i.ToString()) Thread.Sleep(250) Next i Console.WriteLine("{0} finished counting.", threadName) End Sub End Class
using System; using System.Threading; class Test { static void Main() { BackgroundTest shortTest = new BackgroundTest(10); Thread foregroundThread = new Thread(new ThreadStart(shortTest.RunLoop)); foregroundThread.Name = "ForegroundThread"; BackgroundTest longTest = new BackgroundTest(50); Thread backgroundThread = new Thread(new ThreadStart(longTest.RunLoop)); backgroundThread.Name = "BackgroundThread"; backgroundThread.IsBackground = true; foregroundThread.Start(); backgroundThread.Start(); } } class BackgroundTest { int maxIterations; public BackgroundTest(int maxIterations) { this.maxIterations = maxIterations; } public void RunLoop() { String threadName = Thread.CurrentThread.Name; for(int i = 0; i < maxIterations; i++) { Console.WriteLine("{0} count: {1}", threadName, i.ToString()); Thread.Sleep(250); } Console.WriteLine("{0} finished counting.", threadName); } }
using namespace System; using namespace System::Threading; ref class BackgroundTest { private: int maxIterations; public: BackgroundTest( int maxIterations ) { this->maxIterations = maxIterations; } void RunLoop() { String^ threadName = Thread::CurrentThread->Name; for ( int i = 0; i < maxIterations; i++ ) { Console::WriteLine( "{0} count: {1}", threadName, i.ToString() ); Thread::Sleep( 250 ); } Console::WriteLine( "{0} finished counting.", threadName ); } }; int main() { BackgroundTest^ shortTest = gcnew BackgroundTest( 10 ); Thread^ foregroundThread = gcnew Thread( gcnew ThreadStart( shortTest, &BackgroundTest::RunLoop ) ); foregroundThread->Name = "ForegroundThread"; BackgroundTest^ longTest = gcnew BackgroundTest( 50 ); Thread^ backgroundThread = gcnew Thread( gcnew ThreadStart( longTest, &BackgroundTest::RunLoop ) ); backgroundThread->Name = "BackgroundThread"; backgroundThread->IsBackground = true; foregroundThread->Start(); backgroundThread->Start(); }
.NET Framework
Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0.NET Framework Client Profile
Supported in: 4, 3.5 SP1Portable Class Library
Supported in: Portable Class LibraryWindows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Reference
Other Resources
There is no information about default value of this property.
The default is False
Thx for pointing that out. By default, a newly created thread is a foreground thread, so IsBackground is False.
Glenn Hackney
Common Language Runtime Developer Guidance
[gh] No, setting IsBackground to false makes the thread a foreground thread again. I just tried this, and the thread kept the process alive. If you have a concise repro, use Click to Rate and Give Feedback to send it to me (a bug will be created with my name on it :-). Or if you have the MSDN documentation installed on your computer, click the Send Feedback link in this article and send it that way; again, a bug will be created automatically. -- Glenn