メソッドを実行するためのキューに置きます。メソッドは、スレッド プールのスレッドが使用可能になったときに実行されます。
オーバーロードの一覧
メソッドを実行するためのキューに置きます。メソッドは、スレッド プールのスレッドが使用可能になったときに実行されます。
.NET Compact Framework でもサポート。
[Visual Basic] Overloads Public Shared Function QueueUserWorkItem(WaitCallback) As Boolean
[JScript] public static function QueueUserWorkItem(WaitCallback) : Boolean;
実行するためのキューにメソッドを置き、そのメソッドが使用するデータを含んだオブジェクトを指定します。メソッドは、スレッド プールのスレッドが使用可能になったときに実行されます。
.NET Compact Framework でもサポート。
[Visual Basic] Overloads Public Shared Function QueueUserWorkItem(WaitCallback, Object) As Boolean
[C#] public static bool QueueUserWorkItem(WaitCallback, object);
[C++] public: static bool QueueUserWorkItem(WaitCallback*, Object*);
[JScript] public static function QueueUserWorkItem(WaitCallback, Object) : Boolean;
使用例
[Visual Basic, C#, C++] メモ ここでは、QueueUserWorkItem のオーバーロード形式のうちの 1 つだけについて、使用例を示します。その他の例については、各オーバーロード形式のトピックを参照してください。
' This example shows how to create an object containing task
' information, and pass that object to a task queued for
' execution by the thread pool.
Imports System
Imports System.Threading
' TaskInfo holds state information for a task that will be
' executed by a ThreadPool thread.
Public Class TaskInfo
' State information for the task. These members
' can be implemented as read-only properties, read/write
' properties with validation, and so on, as required.
Public Boilerplate As String
Public Value As Integer
' Public constructor provides an easy way to supply all
' the information needed for the task.
Public Sub New(text As String, number As Integer)
Boilerplate = text
Value = number
End Sub
End Class
Public Class Example
Public Shared Sub Main()
' Create an object containing the information needed
' for the task.
Dim ti As New TaskInfo("This report displays the number {0}.", 42)
' Queue the task and data.
If ThreadPool.QueueUserWorkItem( _
New WaitCallback(AddressOf ThreadProc), ti) Then
Console.WriteLine("Main thread does some work, then sleeps.")
' If you comment out the Sleep, the main thread exits before
' the ThreadPool task has a chance to run. ThreadPool uses
' background threads, which do not keep the application
' running. (This is a simple example of a race condition.)
Thread.Sleep(1000)
Console.WriteLine("Main thread exits.")
Else
Console.WriteLine("Unable to queue ThreadPool request.")
End If
End Sub
' The thread procedure performs the independent task, in this case
' formatting and printing a very simple report.
'
Shared Sub ThreadProc(stateInfo As Object)
Dim ti As TaskInfo = CType(stateInfo, TaskInfo)
Console.WriteLine(ti.Boilerplate, ti.Value)
End Sub
End Class
[C#]
// This example shows how to create an object containing task
// information, and pass that object to a task queued for
// execution by the thread pool.
using System;
using System.Threading;
// TaskInfo holds state information for a task that will be
// executed by a ThreadPool thread.
public class TaskInfo {
// State information for the task. These members
// can be implemented as read-only properties, read/write
// properties with validation, and so on, as required.
public string Boilerplate;
public int Value;
// Public constructor provides an easy way to supply all
// the information needed for the task.
public TaskInfo(string text, int number) {
Boilerplate = text;
Value = number;
}
}
public class Example {
public static void Main() {
// Create an object containing the information needed
// for the task.
TaskInfo ti = new TaskInfo("This report displays the number {0}.", 42);
// Queue the task and data.
if (ThreadPool.QueueUserWorkItem(new WaitCallback(ThreadProc), ti)) {
Console.WriteLine("Main thread does some work, then sleeps.");
// If you comment out the Sleep, the main thread exits before
// the ThreadPool task has a chance to run. ThreadPool uses
// background threads, which do not keep the application
// running. (This is a simple example of a race condition.)
Thread.Sleep(1000);
Console.WriteLine("Main thread exits.");
}
else {
Console.WriteLine("Unable to queue ThreadPool request.");
}
}
// The thread procedure performs the independent task, in this case
// formatting and printing a very simple report.
//
static void ThreadProc(Object stateInfo) {
TaskInfo ti = (TaskInfo) stateInfo;
Console.WriteLine(ti.Boilerplate, ti.Value);
}
}
[C++]
// This example shows how to create an Object* containing task
// information, and pass that Object* to a task queued for
// execution by the thread pool.
#using <mscorlib.dll>
using namespace System;
using namespace System::Threading;
// TaskInfo holds state information for a task that will be
// executed by a ThreadPool thread.
public __gc class TaskInfo
{
// State information for the task. These members
// can be implemented as read-only properties, read/write
// properties with validation, and so on, as required.
public:
String* Boilerplate;
int Value;
// Public constructor provides an easy way to supply all
// the information needed for the task.
TaskInfo(String* text, int number)
{
Boilerplate = text;
Value = number;
}
};
public __gc struct Example
{
// The thread procedure performs the independent task, in this case
// formatting and printing a very simple report.
//
static void ThreadProc(Object* stateInfo)
{
TaskInfo* ti = dynamic_cast<TaskInfo*>(stateInfo);
Console::WriteLine(ti->Boilerplate, __box(ti->Value));
}
};
int main()
{
// Create an object containing the information needed
// for the task.
TaskInfo* ti = new TaskInfo(S"This report displays the number {0}.", 42);
// Queue the task and data.
if (ThreadPool::QueueUserWorkItem(new WaitCallback(0, Example::ThreadProc), ti))
{
Console::WriteLine(S"Main thread does some work, then sleeps.");
// If you comment out the Sleep, the main thread exits before
// the ThreadPool task has a chance to run. ThreadPool uses
// background threads, which do not keep the application
// running. (This is a simple example of a race condition.)
Thread::Sleep(1000);
Console::WriteLine(S"Main thread exits.");
}
else
{
Console::WriteLine(S"Unable to queue ThreadPool request.");
}
return 0;
}
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