Thread::Start Method (Object^)


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Causes the operating system to change the state of the current instance to ThreadState::Running, and optionally supplies an object containing data to be used by the method the thread executes.

Namespace:   System.Threading
Assembly:  mscorlib (in mscorlib.dll)

[HostProtectionAttribute(SecurityAction::LinkDemand, Synchronization = true, 
	ExternalThreading = true)]
void Start(
	Object^ parameter


Type: System::Object^

An object that contains data to be used by the method the thread executes.

Exception Condition

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.

Once a thread is in the ThreadState::Running 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.

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
        void StartThreads()
            // Start a thread that calls a parameterized static method.
            Thread^ newThread = gcnew
                Thread(gcnew ParameterizedThreadStart(Work::DoWork));

            // Start a thread that calls a parameterized instance method.
            Work^ someWork = gcnew Work;
            newThread = gcnew Thread(
                        gcnew ParameterizedThreadStart(someWork,
            newThread->Start("The answer.");

        static void DoWork(Object^ data)
            Console::WriteLine("Static thread procedure. Data='{0}'", 

        void DoMoreWork(Object^ data)
            Console::WriteLine("Instance thread procedure. Data='{0}'", 

//Entry point of example application
int main()
    SystemThreadingExample::Work^ samplework = 
        gcnew SystemThreadingExample::Work();
// This example displays output like the following:
//       Static thread procedure. Data='42'
//       Instance thread procedure. Data='The answer.'

.NET Framework
Available since 2.0
Available since 2.0
Windows Phone Silverlight
Available since 7.0
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