Thread.Start
Method
Definition
Overloads
| Start() |
Causes the operating system to change the state of the current instance to Running. |
| Start(Object) |
Causes the operating system to change the state of the current instance to Running, and optionally supplies an object containing data to be used by the method the thread executes. |
Start()
Causes the operating system to change the state of the current instance to Running.
public void Start ();
The thread has already been started.
There is not enough memory available to start this thread.
Examples
The following example creates and starts a thread.
using namespace System;
using namespace System::Threading;
public ref class ThreadWork
{
public:
static void DoWork()
{
for ( int i = 0; i < 3; i++ )
{
Console::WriteLine( "Working thread..." );
Thread::Sleep( 100 );
}
}
};
int main()
{
ThreadStart^ myThreadDelegate = gcnew ThreadStart(&ThreadWork::DoWork);
Thread^ thread1 = gcnew Thread( myThreadDelegate );
thread1->Start();
for ( int i = 0; i < 3; i++ )
{
Console::WriteLine( "In main." );
Thread::Sleep( 100 );
}
}
// The example displays output like the following:
// In main.
// Working thread...
// In main.
// Working thread...
// In main.
// Working thread...
using System;
using System.Threading;
public class ThreadWork
{
public static void DoWork()
{
for(int i = 0; i<3;i++) {
Console.WriteLine("Working thread...");
Thread.Sleep(100);
}
}
}
class ThreadTest
{
public static void Main()
{
Thread thread1 = new Thread(ThreadWork.DoWork);
thread1.Start();
for (int i = 0; i<3; i++) {
Console.WriteLine("In main.");
Thread.Sleep(100);
}
}
}
// The example displays output like the following:
// In main.
// Working thread...
// In main.
// Working thread...
// In main.
// Working thread...
Imports System.Threading
Public Class ThreadWork
Public Shared Sub DoWork()
Dim i As Integer
For i = 0 To 2
Console.WriteLine("Working thread...")
Thread.Sleep(100)
Next i
End Sub
End Class
Class ThreadTest
Public Shared Sub Main()
Dim thread1 As New Thread(AddressOf ThreadWork.DoWork)
thread1.Start()
Dim i As Integer
For i = 0 To 2
Console.WriteLine("In main.")
Thread.Sleep(100)
Next
End Sub
End Class
' The example displays output like the following:
' In main.
' Working thread...
' In main.
' Working thread...
' In main.
' Working thread...
Remarks
Once a thread is in the ThreadState state, the operating system can schedule it for execution. The thread begins executing at the first line of the method represented by the ThreadStart or ParameterizedThreadStart delegate supplied to the thread constructor. Note that the call to Start does not block the calling thread.
Note
If this overload is used with a thread created using a ParameterizedThreadStart delegate, null is passed to the method executed by the thread.
Once the thread terminates, it cannot be restarted with another call to Start.
Start(Object)
Causes the operating system to change the state of the current instance to Running, and optionally supplies an object containing data to be used by the method the thread executes.
public void Start (object parameter);
- parameter
- Object
An object that contains data to be used by the method the thread executes.
The thread has already been started.
There is not enough memory available to start this thread.
This thread was created using a ThreadStart delegate instead of a ParameterizedThreadStart delegate.
Examples
The following example creates a ParameterizedThreadStart delegate with a static method and an instance method.
using namespace System;
using namespace System::Threading;
namespace SystemThreadingExample
{
public ref class Work
{
public:
void StartThreads()
{
// Start a thread that calls a parameterized static method.
Thread^ newThread = gcnew
Thread(gcnew ParameterizedThreadStart(Work::DoWork));
newThread->Start(42);
// Start a thread that calls a parameterized instance method.
Work^ someWork = gcnew Work;
newThread = gcnew Thread(
gcnew ParameterizedThreadStart(someWork,
&Work::DoMoreWork));
newThread->Start("The answer.");
}
static void DoWork(Object^ data)
{
Console::WriteLine("Static thread procedure. Data='{0}'",
data);
}
void DoMoreWork(Object^ data)
{
Console::WriteLine("Instance thread procedure. Data='{0}'",
data);
}
};
}
//Entry point of example application
int main()
{
SystemThreadingExample::Work^ samplework =
gcnew SystemThreadingExample::Work();
samplework->StartThreads();
}
// This example displays output like the following:
// Static thread procedure. Data='42'
// Instance thread procedure. Data='The answer.'
using System;
using System.Threading;
public class Work
{
public static void Main()
{
// Start a thread that calls a parameterized static method.
Thread newThread = new Thread(Work.DoWork);
newThread.Start(42);
// Start a thread that calls a parameterized instance method.
Work w = new Work();
newThread = new Thread(w.DoMoreWork);
newThread.Start("The answer.");
}
public static void DoWork(object data)
{
Console.WriteLine("Static thread procedure. Data='{0}'",
data);
}
public void DoMoreWork(object data)
{
Console.WriteLine("Instance thread procedure. Data='{0}'",
data);
}
}
// This example displays output like the following:
// Static thread procedure. Data='42'
// Instance thread procedure. Data='The answer.'
Imports System.Threading
Public Class Work
Shared Sub Main()
' Start a thread that calls a parameterized static method.
Dim newThread As New Thread(AddressOf Work.DoWork)
newThread.Start(42)
' Start a thread that calls a parameterized instance method.
Dim w As New Work()
newThread = New Thread(AddressOf w.DoMoreWork)
newThread.Start("The answer.")
End Sub
Public Shared Sub DoWork(ByVal data As Object)
Console.WriteLine("Static thread procedure. Data='{0}'",
data)
End Sub
Public Sub DoMoreWork(ByVal data As Object)
Console.WriteLine("Instance thread procedure. Data='{0}'",
data)
End Sub
End Class
' This example displays output like the following:
' Static thread procedure. Data='42'
' Instance thread procedure. Data='The answer.'
Remarks
Once a thread is in the ThreadState state, the operating system can schedule it for execution. The thread begins executing at the first line of the method represented by the ThreadStart or ParameterizedThreadStart delegate supplied to the thread constructor. Note that the call to Start does not block the calling thread.
Once the thread terminates, it cannot be restarted with another call to Start.
This overload and the ParameterizedThreadStart delegate make it easy to pass data to a thread procedure, but the technique is not type safe because any object can be passed to this overload. A more robust way to pass data to a thread procedure is to put both the thread procedure and the data fields into a worker object. For more information, see Creating Threads and Passing Data at Start Time.