更新:2007 年 11 月
命名空间:
System.Windows.Forms 程序集:
System.Windows.Forms(在 System.Windows.Forms.dll 中)
Public Overridable Property Enabled As Boolean
Dim instance As Timer
Dim value As Boolean
value = instance.Enabled
instance.Enabled = value
public virtual bool Enabled { get; set; }
public:
virtual property bool Enabled {
bool get ();
void set (bool value);
}
/** @property */
public boolean get_Enabled()
/** @property */
public void set_Enabled(boolean value)
public function get Enabled () : boolean
public function set Enabled (value : boolean)
当值为 true 时,计时器不受“垃圾回收”的释放。
调用 Start 方法与将 Enabled 设置为 true 等效。同样地,调用 Stop 方法与将 Enabled 设置为 false 等效。
下面的示例实现简单的间隔计时器,该计时器每五秒钟发一次警报。当发生警报时,MessageBox 显示该警报已启动次数的计数,并询问用户计时器是否应继续运行。
Public Class Class1
Private Shared myTimer As New System.Windows.Forms.Timer()
Private Shared alarmCounter As Integer = 1
Private Shared exitFlag As Boolean = False
' This is the method to run when the timer is raised.
Private Shared Sub TimerEventProcessor(myObject As Object, _
myEventArgs As EventArgs)
myTimer.Stop()
' Displays a message box asking whether to continue running the timer.
If MessageBox.Show("Continue running?", "Count is: " & alarmCounter, _
MessageBoxButtons.YesNo) = DialogResult.Yes Then
' Restarts the timer and increments the counter.
alarmCounter += 1
myTimer.Enabled = True
Else
' Stops the timer.
exitFlag = True
End If
End Sub
Public Shared Sub Main()
' Adds the event and the event handler for the method that will
' process the timer event to the timer.
AddHandler myTimer.Tick, AddressOf TimerEventProcessor
' Sets the timer interval to 5 seconds.
myTimer.Interval = 5000
myTimer.Start()
' Runs the timer, and raises the event.
While exitFlag = False
' Processes all the events in the queue.
Application.DoEvents()
End While
End Sub
End Class
public class Class1 {
static System.Windows.Forms.Timer myTimer = new System.Windows.Forms.Timer();
static int alarmCounter = 1;
static bool exitFlag = false;
// This is the method to run when the timer is raised.
private static void TimerEventProcessor(Object myObject,
EventArgs myEventArgs) {
myTimer.Stop();
// Displays a message box asking whether to continue running the timer.
if(MessageBox.Show("Continue running?", "Count is: " + alarmCounter,
MessageBoxButtons.YesNo) == DialogResult.Yes) {
// Restarts the timer and increments the counter.
alarmCounter +=1;
myTimer.Enabled = true;
}
else {
// Stops the timer.
exitFlag = true;
}
}
public static int Main() {
/* Adds the event and the event handler for the method that will
process the timer event to the timer. */
myTimer.Tick += new EventHandler(TimerEventProcessor);
// Sets the timer interval to 5 seconds.
myTimer.Interval = 5000;
myTimer.Start();
// Runs the timer, and raises the event.
while(exitFlag == false) {
// Processes all the events in the queue.
Application.DoEvents();
}
return 0;
}
}
public ref class Class1
{
private:
static System::Windows::Forms::Timer^ myTimer = gcnew System::Windows::Forms::Timer;
static int alarmCounter = 1;
static bool exitFlag = false;
// This is the method to run when the timer is raised.
static void TimerEventProcessor( Object^ /*myObject*/, EventArgs^ /*myEventArgs*/ )
{
myTimer->Stop();
// Displays a message box asking whether to continue running the timer.
if ( MessageBox::Show( "Continue running?", String::Format( "Count is: {0}", alarmCounter ), MessageBoxButtons::YesNo ) == DialogResult::Yes )
{
// Restarts the timer and increments the counter.
alarmCounter += 1;
myTimer->Enabled = true;
}
else
{
// Stops the timer.
exitFlag = true;
}
}
public:
static void Main()
{
/* Adds the event and the event handler for the method that will
process the timer event to the timer. */
myTimer->Tick += gcnew EventHandler( TimerEventProcessor );
// Sets the timer interval to 5 seconds.
myTimer->Interval = 5000;
myTimer->Start();
// Runs the timer, and raises the event.
while ( exitFlag == false )
{
// Processes all the events in the queue.
Application::DoEvents();
}
}
};
int main()
{
Class1::Main();
}
public class Class1
{
private static System.Windows.Forms.Timer myTimer =
new System.Windows.Forms.Timer();
private static int alarmCounter = 1;
private static boolean exitFlag = false;
// This is the method to run when the timer is raised.
private static void TimerEventProcessor(Object myObject,
EventArgs myEventArgs)
{
myTimer.Stop();
// Displays a message box asking whether to continue running the timer.
if (MessageBox.Show("Continue running?", "Count is: "
+ alarmCounter, MessageBoxButtons.YesNo).Equals(DialogResult.Yes)) {
// Restarts the timer and increments the counter.
alarmCounter += 1;
myTimer.set_Enabled(true);
}
else {
// Stops the timer.
exitFlag = true;
}
} //TimerEventProcessor
public static void main(String[] args)
{
/* Adds the event and the event handler for the method that will
process the timer event to the timer.
*/
myTimer.add_Tick(new EventHandler(TimerEventProcessor));
// Sets the timer interval to 5 seconds.
myTimer.set_Interval(5000);
myTimer.Start();
// Runs the timer, and raises the event.
while (exitFlag == false) {
// Processes all the events in the queue.
Application.DoEvents();
}
return;
} //main
} //Class1
Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC
.NET Framework 和 .NET Compact Framework 并不是对每个平台的所有版本都提供支持。有关支持的版本的列表,请参见.NET Framework 系统要求。
.NET Framework
受以下版本支持:3.5、3.0、2.0、1.1、1.0
.NET Compact Framework
受以下版本支持:3.5、2.0、1.0
参考