如何使网页/网址在计时器滴答事件中每隔X秒自动刷新一次？

Question

我有这条线在计时器滴答事件：

HttpContext.Current.Response.Redirect("https://www.facebook.com/groups/mygroup/"); 

但即时得到异常电流为null。

Object reference not set to an instance of an object 

System.NullReferenceException was unhandled 
    HResult=-2147467261 
    Message=Object reference not set to an instance of an object. 
    Source=ScrollLabel 
    StackTrace: 
     at ScrollLabelTest.Form1.timer1_Tick(Object sender, EventArgs e) in e:\scrolllabel\ScrollLabel\ScrollLabel\Form1.cs:line 272 
     at System.Windows.Forms.Timer.OnTick(EventArgs e) 
     at System.Windows.Forms.Timer.TimerNativeWindow.WndProc(Message& m) 
     at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) 
     at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg) 
     at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData) 
     at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context) 
     at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context) 
     at System.Windows.Forms.Application.Run(Form mainForm) 
     at ScrollLabelTest.Program.Main() in e:\Program.cs:line 18 
     at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args) 
     at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) 
     at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() 
     at System.Threading.ThreadHelper.ThreadStart_Context(Object state) 
     at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) 
     at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) 
     at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) 
     at System.Threading.ThreadHelper.ThreadStart() 
    InnerException: 

Form1上线272：

HttpContext.Current.Response.Redirect("https://www.facebook.com/groups/mygroup/"); 

Answer 1

如果你在Windows窗体中使用这种没有HttpContext的，所以参考HttpContext.Current将抛出一个空引用异常。